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Samir rafla principles of cardiology pages 112 to end
 

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    Samir rafla principles of cardiology pages 112 to end Samir rafla principles of cardiology pages 112 to end Document Transcript

    • Samir Rafla: Principles of Cardiology pages 112 to end HYPERTENSION AND HEART DISEASEHypertension is a major risk factor for cardiovascular morbidity and mortality. Itaccelerates the process of atherosclerosis in the coronary, cerebral and renal arteries,as well as increasing the workload of the heart. As a result, the hypertensive patient isat risk of developing myocardial infarction, stroke, renal failure and congestivecardiac failure. In total, hypertension is probably directly or indirectly responsible for10-20% of all deaths.The normal blood pressure ranges from 90 – 139 mmHg systolic and 60 – 89diastolic. The BP is classified as follows Category Systolic DiastolicNormal <130 <85High normal 130-139 85-89 HypertensionStage I (mild) 140-159 90-99Stage II (moderate) 160-179 100-109Stage III (severe) >180 >110Stage IV (very severe) >210 >120Malignant hypertension is said to be present when there is papillodema anddiastolic BP > 130.Isolated systolic hypertension when diastolic BP < 90 and systolic BP 140-159(borderline isolated systolic hypertension; > 160 mmHg (isolated systolichypertension).Prevalence of hypertension: According to survey done by Prof. Mohsen Ibrahim,high BP was found in 26% of Egyptian population above age 25 years (thus about 9million Egyptians have hypertension). 112
    • Blood pressure is usually measured in the arm. The usual method involves a ‘cuff’which is wrapped around the upper arm. The cuff contains an inflatable rubberbladder. The cuff is then inflated with air until the pressure from the cuff occludes thebrachial artery. The cuff is then slowly deflated and the pressure in the cuff iscontinuously measured using either a mercury manometer or an aneroid manometer.At the same time as the operator regulates the deflation of the cuff, he or she listenswith a stethoscope over the brachial artery immediately distal to the cuff. As the cuffis deflating, the pressure at which regular sounds first appear over the brachial arteryis taken as the systolic blood pressure. As the pressure continues to fall, the soundsbecome muffled and then disappear. The pressure at which the sounds disappearcompletely is the diastolic pressure.AETIOLOGY OF HYPERTENSIONIn 95% of patients with high blood pressure, no specific cause can be identified. Thiscondition is termed ‘essential’ or ‘primary’ hypertension. In approximately 5% ofhypertensive patients, a specific cause can be identified and the hypertension istermed ‘secondary’. Although secondary hypertension accounts for a small minorityof all hypertensive patients, it is important to identify this condition because specificand potentially curative treatment may be available.Essential hypertension: Causes (predisposing factors):Genetic influencesDietary influencesThere is an undoubted relationship between weight and blood pressure. Weight lossin the obese substantially lowers the blood pressure.Excessive sodium chloride intake.High intake of saturated fats.High alcohol consumption.Cigarette smoking. 113
    • Physical activity: Physical exercise can reduce blood pressure in hypertensivesubjects. This suggests that inactivity may play a role in the genesis of hypertensionin some individuals.Hormonal changesThe adrenergic and renin—angiotensin systems, has a role in the genesis of essentialhypertension.Haemodynamic changesThere is good evidence that baroreceptors are reset in hypertension.Secondary hypertensionThe most common causes of secondary hypertension are renal disease, adrenaldisease, coarctation of the aorta and drug-related hypertension.Renal diseaseAll forms of parenchymal renal disease can be associated with significanthypertension. These include acute and chronic glomerulonephritis, chronicpyelonephritis and polycystic kidney disease. Control of the blood pressure in all ofthese conditions is important and slows the progression of renal damage.Renal artery stenosis as a cause of hypertension deserves special consideration. Inthis condition, the stenosis may be unilateral or bilateral and may take the form of afibromuscular narrowing in young patients or atheromatous narrowing in olderpatients, who will often have evidence of atherosclerosis elsewhere. Renal arterystenosis results in ischaemia of the kidney with high circulating levels of angiotensinII. High levels of angiotensin II then lead to hypertension by two differentmechanisms. Hypertension in these patients is often relatively resistant to drugtreatment. Angiotensin converting enzyme (ACE) inhibitors, by preventing therelease of angiotensin II, will lower the blood pressure markedly but should beavoided in patients suspected of having renal artery stenosis because they reducerenal perfusion and may result in renal infarction. If a patient has bilateral renal arterystenoses, the introduction of an ACE inhibitor can precipitate acute renal failure. 114
    • Fig: The renin—angiotensin system.Investigation of suspected ‘renal’ hypertension - Abdominal ultrasonographyprovides a simple non-invasive means of assessing renal anatomy in patients with asuspected renal cause for hypertension. In patients with chronic nephritis, kidney sizeis reduced. In patients with pyelonephritis, there is likely to be dilatation of thecalyceal system. In unilateral renal artery stenosis, kidney size is reduced on the sideof the stenosis. If renal artery stenosis is suspected, then renal arteriography remainsthe investigation of choice although the diagnosis can now often be made using eithermultislice CT or magnetic resonance imaging (MRI). If the patient is shown to haveeither unilateral or bilateral renal artery stenosis, then renal revascularization by renalartery angioplasty should be considered.Endocrine diseaseCushing’s syndromeThis results from cortisol excess and may be due to hyperplasia of the adrenal cortex,adrenal tumours, or to the excessive administration of glucocorticoids or 115
    • adrenocorticotrophic hormone (ACTH). Adrenal hyperplasia is often the result ofincreased ACTH production by a pituitary microadenoma.Hypertension, which occurs in more than 50% of cases, may be severe and mayproceed to the malignant phase. Other features of the syndrome are muscle weakness,osteoporosis, purple cutaneous striae, obesity of the trunk, a ‘buffalo’ hump, a ‘moon’facies and diabetes mellitus. There may also be hirsutism, amenorrhoea, a liability tospontaneous bruising, and dependent oedema.Diagnosis: The diagnosis should be suggested by the combination of hypertension,diabetes and truncal obesity. Investigations include:• excessive 24-h urinary free cortisol excretion• failure to suppress plasma cortisol levels following dexamethasoneadministration• the ACTH levels are valuable in determining the cause, being high with pituitarytumours and low if the adrenal is responsible• CT or MRI imaging of the adrenal glands.Management: Treatment depends upon the aetiology of the condition. Surgicalremoval of one or both adrenal glands or of a pituitary tumour may be necessaryPrimary aldosteronismAldosterone, which is secreted by the zona glomerulosa of the adrenal cortex,promotes sodium reabsorption and potassium excretion in the distal tubules of thekidney. Normally, aldosterone secretion is largely regulated by angiotensin, but inprimary aldosteronism there is an overproduction of aldosterone as a result of anadrenal cortical adenoma (Conn’s syndrome) or bilateral hyperplasia; angiotensinand, therefore, plasma renin levels are abnormally low. The condition occurs mostoften in young and middle-aged females. Because of the mode of action ofaldosterone, the symptoms and signs are related to sodium retention, hypokalaemiaand hypertension. Frequently, the patient presents with mild to moderate 116
    • hypertension, but the predominant complaints are those of muscle weakness,headache, thirst and polyuria. The hypertension is seldom severe and malignantchanges are rare. There is usually hypokalaemia, with a serum potassium level of lessthan 3.0 mmol/L and a serum sodium concentration that is normal or high.Characteristically, there is a metabolic alkalosis and a low serum chloride level. Thediagnosis should be suspected in patients with hypertension and hypokalaemia,particularly if this is associated with hypernatraemia. However, hypokalaemia is notuncommon in other hypertensive patients, particularly if they have been treated withdiuretics. Furthermore, patients with malignant hypertension develop ‘secondaryaldosteronism’ with low serum potassium. These patients usually do not have highserum sodium.Diagnosis. The diagnosis is suggested by:• hypokalaemia, persisting after stopping diuretic therapy• excessive urinary potassium loss• elevated plasma aldosterone levels• suppressed renin levels which fail to rise on assumption of an upright posture• CT or MRI imaging is now the investigation of choice in establishing thepresence of an adenoma and differentiating this from hyperplasia.Management. Adenomas should be removed surgically. Patients with hyperplasiashould be treated medically with spironolactone or amiloride, which antagonize theactions of aldosterone.PhaeochromocytomaPhaeochromocytoma arises in chromaffin tissue, usually in the adrenal gland. It issometimes described as the ‘10% tumour’. This is because 10% are said to ariseoutside the adrenal gland, 10% are malignant and 10% are bilateral. The tumoursusually secrete noradrenaline (norepinephrine), but adrenaline (epinephrine) maypredominate.Phaeochromocytomas may produce either paroxysmal or persistent hypertension. Theparoxysms are associated with the sudden onset of bilateral headache, and with 117
    • perspiration, palpitations and pallor (features often regarded as neurotic). The attacksusually last from a few minutes to an hour. If the hypertension is persistent, theclinical picture is that of severe hypertension, often of the malignant variety. Becauseof the hypermetabolic state induced by the phaeochromocytoma, the patients arerarely obese.Diagnosis: The diagnosis should be suspected in any severe case of hypertension,particularly if the hypertension is paroxysmal. The diagnosis is confirmed by:• excessive excretion of the catecholamine metabolite vanilmandelic acid (VMA)in the urine is a useful screening test• urine and plasma catecholamine levels• CT scanning to localize the tumour.Management. Phaeochromocytomas should be removed surgically. This is apotentially hazardous procedure and requires close control of the blood pressure andcareful anaesthesia. Beta-adrenergic blocking drugs should not be used alone becauseunopposed alpha-adrenergic activation may aggravate hypertension and lead toserious complications such as stroke. This can be avoided by the initial use of analpha-adrenergic blocking drug. The non-competitive alpha-antagonistphenoxybenzamine is frequently chosen. Once alpha-adrenergic blockade is fullyestablished, beta-blockade can be added.Coarctation of the aortaThis is a congenital condition associated with a narrowing of the lumen of the aortajust beyond the origin of the left subclavian artery. See page 33.PATHOPHYSIOLOGY OF HYPERTENSIONThe high blood pressure in essential hypertension is due to increased peripheralvascular resistance as a result of widespread constriction of the arterioles and smallarteries. The cardiac output and the viscosity of the blood are normal (usually). In theearlier stages, the hypertension is largely due to increased arteriolar muscle tone, but 118
    • subsequently, structural alterations take place in the arterioles. These changes may account for the fact that hypertension tends to beget (induce) further hypertension, and the removal of the cause of hypertension does not necessarily lead to a fall in the blood pressure to normal. In the heart, there are two major consequences of sustained hypertension. The increased work of the heart imposed by the higher resistance results in hypertrophy of the myocardial cells. As this process progresses, the myocardial hypertrophy may exceed the coronary blood supply; this occurs particularly in the subendocardial layers which are the most vulnerable to ischaemia; ultimately, leads to heart failure. The second effect of hypertension is to accelerate the development of atherosclerosis. This occurs not only in the coronary arteries but also in the cerebral arteries, particularly those of the basal ganglia, and in the renal arteries. The mechanism of this action is long-standing mechanical stresses; in experimental situations, hypertension, like cigarette smoking and hypercholesterolaemia, has been shown to induce dysfunction of the endothelial layer of the coronary arteries which, in turn, is thought to start the development of atherosclerosis. Examination and Investigation of the Hypertensive Patient Examination and investigation should be directed towards the detection of an underlying cause of hypertension (see secondary hypertension) and the assessment of end-organ damage, which may influence the decision to treat the patient. Blood pressure levels should be recorded after the patient has been lying quietly for 5 mm. Examination of the hypertensive patient Clinical examination should take note of: Signs suggestive of secondary hypertension• Features of endocrine abnormalities, particularly Cushing’s syndrome• Multiple neurofibromatoma — present in 5% of patients with phaeochromocytoma• Inappropriate tachycardia, suggesting catecholamine excess• Abdominal or loin bruits, suggesting renal artery stenosis 119
    • • Renal enlargement (suggestive of polycystic kidney disease)• Radial-femoral delay, due to coarctation of the aorta. Signs suggestive of end-organ damage• A forcible and displaced apex beat due to left ventricular hypertrophy• Added heart sounds. A fourth sound may be audible, reflecting decreased ventricular compliance. As failure develops a third sound may occur.• Fundal examination to detect hypertensive retinopathy. Fundoscopy: Grading:• grade I - increased tortuosity of the retinal arteries with increased reflectiveness, termed silver wiring• grade 2 - grade I with the addition of compression of the veins at arteriovenous crossings (AV nipping)• grade 3 - grade 2 with the addition of flame-shaped haemorrhages and ‘cotton wool’ exudates• grade 4- grade 3 with the addition of papilloedema — the optic disc is pink with blurred edges and the optic cup is obliterated. Investigation of the hypertensive patient• ECG. This is usually normal in patients with mild hypertension but may show evidence of left ventricular hypertrophy. This is characterized by tall R waves in the lateral chest leads and deep S waves in the anteroseptal leads. LVH is said to be present if the sum of the S wave in VI and the R wave in V5 or V6 exceeds 35 mm. In severe hypertrophy, or if there is accompanying ischaemic heart disease, the T waves in the lateral chest leads become flattened and then inverted, and the ST segment may show down-sloping depression in the same leads. This is the so-called ‘left ventricular hypertrophy and strain’ pattern (Fig. 14.4) which carries a high risk of major events including sudden death (30—40% 5-year mortality rate).• Urinalysis. Proteinuria, hyaline and granular casts may be found when there is renal disease or malignant hypertension. 120
    • • Urea and electrolytes. A raised level of urea suggests renal impairment, which may be the cause or an effect of hypertension. A low serum potassium concentration in the absence of diuretic therapy might suggest Conn’s or Cushing’s syndrome.• Lipids. An increased level of cholesterol is a risk factor for cardiovascular events, which may require specific treatment and which should be monitored in all hypertensive patients. Fig: ECG showing left ventricular hypertrophy and ‘strain’ in a patient with severe hypertension. This pattern is characterized by large voltages in the chest leads and the presence of ST segment depression and T wave inversion in leads V5 and V6. The following additional investigations may also be helpful: • 24-h ambulatory blood pressure monitoring. • Echocardiography. Echocardiography is much more sensitive than the ECG for the detection of left ventricular hypertrophy. • Detailed investigation of suspected secondary hypertension. This may involve CT or MRI of the adrenal glands, MRI renal angiography and 24-h urine collections for catecholamines. 121
    • It is impractical to screen all hypertensive patients for secondary causes ofhypertension. Selection of patient groups for further investigation is arbitrary, butinvestigation is particularly appropriate in the following groups:• young patients under 40 years of age• patients with malignant hypertension• patients resistant to antihypertensive therapy• patients with unusual symptoms (such as sweating attacks or weakness) whichmight suggest an underlying cause• patients with abnormal renal function, proteinuria or haematuria• patients with hypokalaemia off diuretic therapy.THE DECISION TO TREATAlmost all patients with untreated malignant hypertension die within 1 year. Death isusually due to uraemia but heart failure and cerebrovascular accidents are common.In these patients, and in those with moderate to severe hypertension, there is clearevidence that treatment prolongs life.Any person with mild persistent hypertension should be treated. Life stylemodification is adopted and observing patient for 3 months, if BP does not normalizetreatment to be started.Other risk factors should also be taken into account when deciding whether to initiatetherapy. Factors such as age, sex, hypercholesterolaemia, cigarette smoking anddiabetes are not simply additive but multiplicative in terms of the risk to theindividual. Patients with multiple risk factors, therefore, are more likely to benefitfrom antihypertensive treatment than those with the same level of blood pressure butno other risk factors.In deciding when to initiate treatment, two patient groups require specific mention.These are the elderly (patients over 70 years of age) and those with isolated systolic 122
    • hypertension (systolic blood pressure greater than 160 mmHg and diastolic bloodpressure less than 95 mmHg). Recent studies have demonstrated that both elderlypatients and those with isolated systolic hypertension derive very considerable benefitfrom treatment.In patients with mild to moderate hypertension, treatment has effectively eliminateddeath from cardiac failure and has reduced the incidence of fatal and non-fatal strokesby around 35—40%. TREATMENT OF HYPERTENSIONMalignant hypertension, demonstrating retinal haemorrhages and exudates, requiresurgent hospitalization and treatment. In all hypertensive patients, attention should bepaid to non-pharmacological interventions that will reduce blood pressure and obviatethe need for drug therapy in mild hypertensives, particularly if there is no evidence ofend-organ damage. These include• Weight reduction.• Regular exercise.• Stop smoking.• Reduce cholesterol intake and salt intake.• Management of stress.Drugs used in the treatment of hypertensionBeta-adrenoceptor blocking drugsBeta-blockers are effective antihypertensive drugs. They are more effective whencombined with a diuretic or other antihypertensive drugs but are often sufficient ontheir own and produce no marked orthostatic effects. These drugs may exacerbateobstructive airway disease and intermittent claudication, and should probably beavoided in patients with these conditions. Minor side-effects, such as fatigue and coldextremities, are relatively common and disappear on stopping the drug. 123
    • Thiazide diureticsInitially, plasma volume and cardiac output may be reduced, but these values laternormalize. Undesirable metabolic effects of thiazides include hypokalaemia,hyperuricaemia, hypercholesterolaemia and hyperglycaemia. With the currently usedlow doses of thiazides these effects are small.ACE inhibitorsThis class includes captopril, enalapril, ramipril, lisinopril and perindopril. Thesedrugs block the enzyme that converts angiotensin I to angiotensin II. They cause afall in blood pressure by reducing systemic vascular resistance, without having anymajor effect on heart rate and cardiac output. The fall in systemic vascular resistanceis probably mainly due to a reduction in plasma angiotensin II levels, but there is alsoa secondary fall in aldosterone concentration.ACE inhibitors are effective alone in all grades and types of hypertension, but theiraction is potentiated by diuretics. A small rise in plasma urea and creatinine values isnormal with ACE inhibitors but a marked increase may indicate unsuspected renalartery stenosis and is an indication for stopping the drug and considering renalangiography by MSCT. Hyperkalaemia can occur because of the antialdosteroneeffects; therefore, concomitant use of ACE inhibitors and potassium-sparing diureticsis not recommended. Profound hypotension may occasionally be induced on firstcommencing treatment but this is usually seen only in patients who are alreadyhypovolaemic as a result of high-dose diuretic therapy. This can be avoided byomitting diuretics on the day of starting the ACE inhibitor and also by starting with asmall dose.Cough is a particularly troublesome side-effect, occurring in some 15 % of patients.Other side-effects include taste disorders, nausea, diarrhoea, rashes, neutropenia andproteinuria. Acute angioneurotic oedema is a rare but serious side-effect which occursin 0.1—0.2% of patients and is more common in black patients. 124
    • Summary: Angiotensin Converting enzyme inhibitors (A.C.E.)Types: a- Captopril. b- Benzapril, Perindopril, Enalapril. c- Lisinopril. Fosinopril.Mechanism of actions: - Inhibition of circulating A.C.E. - Inhibition of tissue A.C.E.Advantage: - No metabolic side effect. - Improvement in glucose tolerance and insulin resistance. - Reno-protective. - Cardiac protection: prevent cardiac dilatation and reversal of L.V.H.Special indications: 1- H.T with C.H.F. 2- H.T with L.V.H. 3- Following myocardial infarction. 4- H.T. with type II diabetes and diabetic nephropathy. 5- H.T. with peripheral vascular disease. 6- High renin-hypertension. 7- No C.N.S. side effects. 8- No coronary vasoconstriction. 9- Older and younger hypertensivesCautions: Renal insufficiency. Renovascular disease.Contraindications: * Pregnancy. * Bilateral renal artery stenosis.Side effects: Cough, taste disturbance, rash and leucopenia. 125
    • Calcium-blocking drugsThe dihydropyridine group, including nifedipine, nicardipine and amlodipine, all actpredominantly by relaxing vascular smooth muscle and hence lowering peripheralvascular resistance. Side-effects with these agents include headache, flushing andankle swelling.The phenylalkylamine calcium channel blockers, such as verapamil and diltiazem, actmore on the myocardium and conducting tissue. These are free from the vasodilatorside-effects of the dihydropyridine class but do have negative inotropic effects andmay potentiate heart failure.Alpha-blockersThis class includes prazosin, terazosin and doxazosin. These drugs have markedarteriolar and venous vasodilating effects and the initial dose may produce profoundpostural hypotension. For this reason, the first dose should be taken on retiring to bedand the dosage gradually increased over a period of several weeks.Angiotensin receptor antagonistsThese include Losartan, Valsartan, Irbesartan, Telmisartan and Candesartan. Theseagents act by blocking the angiotensin II receptor. They appear to be effective inlowering blood pressure and are relatively free from side-effects. Unlike the ACEinhibitors, they do not cause cough.Other vasodilator agentsDrugs such as hydralazine and minoxidil are not now used as first-line therapy butmay still be useful in combination with other agents when multiple drugs are requiredto control blood pressure. Diazoxide and nitroprusside are very effective vasodilatorsbut are generally used only in hypertensive emergencies.Choice of therapy for the individual patientAll drugs cause side-effects in some people. This is a particular problem in thetreatment of hypertension where patients are usually asymptomatic before the 126
    • commencement of medication. The unexpected development of side-effects will oftencause the patient to stop taking the medication and it is generally better to warnpatients that side-effects may occur.As a first choice, many clinicians would use either a diuretic, such as Indapamide(Natrilix sr) 1.5 mg once daily, or a long-acting beta-blocker, such as atenolol 50—100 mg once daily or bisoprolol 5 mg once daily. ACE inhibitors are more effectivethan other agents in producing regression of left ventricular hypertrophy.The choice of medication is also determined by coexisting disease and the side-effectprofile of a given agent. In patients with angina, for example, a beta-blocker would bea logical choice to treat both the angina and hypertension, whereas diuretics and ACEinhibitors would be preferable in patients with impaired left ventricular function.Beta-blockers should be avoided in patients with asthma or severe heart failure, anddiuretics should be avoided in those patients with gout. ACE inhibitors should beused with caution in patients with impaired renal function.If the response to a single drug is inadequate, a second agent should be added.Particularly useful combinations include:• beta-blocker plus diuretic• beta-blocker plus dihydropyridine calcium antagonist• ACE inhibitor or angiotensin II antagonist plus diureticIf a two-drug regimen does not give adequate blood pressure control, a third or fourthagent can be added If the patient has not already been investigated for secondaryhypertension, this should be considered if the hypertension appears to be resistant todrug treatment It is also important to remember that non-compliance is common inthe treatment of hypertension, and this should be suspected if the blood pressure failsto fall despite the use of multiple drugs 127
    • Hypertensive emergenciesHypertensive emergencies: situations in which the complication occur over a shortperiod of time (hours to days) and need immediate reduction of BP generally by I.V.therapy (situations in which there is an end-organ damage): 1- C.N.S. compromise as in hypertensive encephalopathy, subarachnoid hemorrhage, intracerebral hemorrhage. 2- Severe H.T. with pulmonary edema (Acute LV failure). 3- Severe H.T associated with acute myocardial infarction or unstable angina. 4- Severe H.T associated with eclampsia. 5- Acute aortic dissection. 6- Pheochromocytoma crisis. Hypertensive urgenciesHypertensive urgencies in which the complications occur over a period of days toweeks and require gradual reduction in BP and not associated with end organdamage: 1- Accelerated & malignant H.T. 2- Perioperative & postoperative H.T. 3- Pre-eclampsia. 4- Hypertension with angina & unstable angina. 5- Severe H.T. in kidney transplanted patient. 128
    • AORTIC ANEURYSM AND AORTIC DISSECTIONAortic aneurysm: An aortic aneurysm is defined as a pathologic dilatation to morethan 1.5 times the normal diameter of the aorta. Abdominal aortic aneurysms (AAAs)Are much more common than thoracic aortic aneurysms; up to 75% of aorticaneurysms involve the abdominal aorta. Risk factors include hypertension,hyperlipidemia, tobacco abuse, diabetes mellitus, genetics, and age. There is a male-to-female ratio of 9:1, and most cases (95%) involve the infrarenal aorta.1. Clinical presentation. The majority of AAAs are discovered incidentally onphysical examination or during radiologic or ultrasound evaluation of the abdomen.2. Diagnostic testing: a. Abdominal ultrasound. b. Multi Slice CT. c. Aortography.d. Magnetic resonance imaging.3. Therapya. Medical therapy. - B-Blockers. - Risk factor modification with hypertension andhypercholesterolemia control is important. - Cigarette smoking should be eliminated.b. Percutaneous therapy: Percutaneous catheter repair.c. Surgical therapy. Thoracic aortic aneurysms (TAAs)Are much less common than the abdominal variety.. Diagnostic testing: as above. Therapy: a. Medical therapy. b. Percutaneous therapy. c. Surgical therapy. Aortic dissectionDissection of the aorta is defined as cleavage of the intima from the media andadventitia.A. Epidemiology: The incidence of aortic dissection is thought to be 2.000 cases peryear in the United States. The male- to- female ratio is 2:1. The mortality for 129
    • untreated acute aortic dissection is approximately 1% per hour within the first 48hours. Around 65% of dissections originate in the ascending aorta (Just above theright or noncoronary sinus), 20% in the descending thoracic aorta, 10% in the aorticarch, and the remainder in the abdominal aorta.B. Classification schemes:- Currently in use are three classification schemes based on anatomy. These are theDeBakey, Stanford, and anatomic classification.C- Clinical presentation1. Signs and symptoms- Severe chest and/ or back pain are the presenting symptoms in 74% to 90% of acuteaortic dissections. This pain is of sudden onset, at its maximal level, which contrastswith the pain of MI, which is more gradual in onset. The pain is usually described astearing, ripping, or stabbing. The location of the most severe aspect can help localizethe dissection. Anterior chest discomfort is often associated with ascending aortainvolvement. Intrascapular pain is often associated with DeBakey type I or IIIdissections.- Unequal radial pulse is a very important sign. Severe chest pain with normal ECGshould alert the physician to this possibility.- Less common presentations include CHF (usually due to severe aortic incompetencein proximal dissection), syncope (in 4% to 5 of cases, due to rupture into pericardialspace with resultant tamponade), CVA, paraplegia, or cardiac arrest.2. Physical examination:a. Cardiac:1. Hypertension is often seen with aortic dissection frequently as the cause andoccasionally as a complication. In distal dissections, which involve the renal artery,the increase in blood pressure is a response to renal ischemia.2. Hypotension can be seen in proximal dissection with aortic root involvement,hemopericardium, and tamponade.3. Pseudo-hypotension occurs when the subclavian artery is involved with resultantcompression of the vessel. 130
    • 4. The diastolic murmur of AI (16% to 67%) often indicates root involvement, withdisturbance of normal aortic valve coaptation.b. Neurologic: Findings of cerebrovascular accident occur in 3% to 6% of proximaldissections. Rarely, a dissection of the descending aorta involves the primary vesselto the spinal cord with resultant paraplegia.3. Laboratory examination.a. Chest radiograph findings are suggestive of dissection.b. ECG. The most common finding is left ventricular hypertrophy.D. Etiology and pathology1. Medial degeneration, as in Marfan and Ehlers-Danlos syndromes.a. Aging and uncontrolled hypertension.b. Other associated findings include congenital bicuspid aortic valves.2. Pregnancy increases the risk of dissection.3. Direct trauma is also associated with dissection.E. Diagnostic testing1- Evaluation: define the following points: ascending versus descending aorticinvolvement; site of the intimal tear; presence or absence of AI; presence or absenceof pericardial tamponade; and coronary involvement.2- Magnetic resonance imaging/magnetic resonance angiography.3- Transesophageal echocardiography/transthoracic echocardiography.4- Multi Slice CT. 5- Aortography.F. Therapy. Death in aortic dissection results from progression of the dissectionresulting in either vascular compromise or rupture. Proximal (type A) aorticdissection is universally felt to mandate immediate surgical treatment. This greatlyreduces the risk of poor outcomes (acute AI, CHF, tamponade, and neurologicsequelae) from progression of the dissection and halts the 1% per hour mortality rate.Management of distal (type B) aortic dissections is controversial, but it is generallybelieved that medical management is initially indicated. Surgical interventions arereserved for complication or treatment failure.Difficult situations: 131
    • a- Hypotension and shock: The most likely causes are aortic wall rupture ortamponade.b- Acute MI can be seen in association with a type A dissection. In this setting,thrombolysis is absolutely contraindicated. Lack of flow in the proximal coronaryartery or a flap obstructing the coronary may be visible on TEE.- Medical therapy: a. β-Blockers should be initiated immediately if aortic dissectionis being considered in the differential diagnosis.b. Once the patients is adequately β-blocked, sodium nitroprusside can be initiated- Surgical therapy- Patients with proximal or type A dissection should be taken to the operating roomupon diagnosis.- Patients with type B dissection in whom pain and/or hypertension cannot becontrolled medically, or who have evidence of rupture or end-organ involvement,signifying progression of the dissection, should receive surgical repair. Table . Aortic dissection classification systems Classification Pathologic description STANFORD Type A Any dissection involving the ascending aorta Type B Any dissections not involving the ascending aorta DEBAKEY Type I Entry point in the ascending aorta, extends to the aortic arch and often beyond Type II Confined entirely to the ascending aorta Type III Entry in the descending aorta (distal to left subclavian); extends distally (usually) or proximally (rarely) 132
    • Fig. Anatomic appearances of three different aortic dissection classifications.- Percutaneous therapy. New techniques are emerging in the treatment aorticdissections. The newest of these is the percutaneous intraluminal stent-graft.- Long-term management:- Chronic management of distal (type B) aortic dissections is an extension of theacute management. Aggressive blood pressure control is obtained with oral agentssuch as atenolol, metoprolol, labetalol, carvedilol or diltiazem.- In the event of treatment failure, these patients should always be considered forsurgical treatment. Failure is defined as evidence of aortic leak, progression withvisceral organ involvement, recurrent pain, or AI. 133
    • DISEASES OF THE PERIPHERAL ARTERIES AND VEINSDefinition: Peripheral arterial diseases are abnormalities that impair the ability of thecirculation to deliver blood to lower extremities.Etiology: Atherosclerosis is the most common cause of arterial disease of the lowerextremities. Risk factors for the development and progression of Atheroscleroticdisease include smoking, lipid abnormalities, diabetes mellitus, hypertension, andhomocysteinemia. The arteritides (i.e., giant-cell arteritis, Takayasu’s disease,Buerger’s disease) can be contributory and due to an inflammatory and / orautoimmune process. Other important etiologies of compromised blood flow to thelower extremities are emboli, dissection, trauma, vasoconstrictive medications, andprofound systemic shock.Clinical manifestationsHistoryIntermittent claudication is the classic symptom of chronic lower extremity arterialinsufficiency. This usually presents as calf fatigue and cramping with exercise that isrelieved promptly by rest. Progression of disease with involvement of multiple levelsand inadequate collateral circulation can result in pain with minimal exertion or atrest. Rest pain presents as a severe burning discomfort in the foot and may progress toactual tissue necrosis. Acute ischemia produces excruciating pain with progressivesensory and motor deficits.PHYSICAL EXAMINATION The hallmark of peripheral occlusive disease is diminished or absent pulses Tests performed in evaluation (leg raising tests).DIAGNOSTIC EVALUATIONDoppler ultrasound can very accurately detect the presence of lower extremity arterialinsufficiency. Multi slice CT is diagnostic. Contrast arteriography remains the “goldstandard” to define the presence and severity of arterial disease and is reserved todefine anatomy prior to operative intervention. 134
    • TREATMENT: MEDICAL- Cessation of smoking.- An exercise program that stresses daily activity.- Lipid abnormalities should be aggressively treated.- Diabetes requires both strict control of their blood glucose and preventive foot care.Pharmacologic intervention with pentoxifylline may benefit some patients withclaudication (dose: 400 mg PO tid), and Cilostazol 100 mg (Pletaal). A trial ofvasodilators is indicated in patients with vasospastic disorders.SURGICAL/ INTERVENTIONALAngioplasty and stenting of the common iliac artery has the best durability.Raynaud’s phenomenon: Pathology: Vasospasm of digital vessels precipitated bycold and relieved by heat. Clinical features: Underlying causes: Arterial occlusivedisease; connective tissue disease; neurologic diseases; ingestion of vaso-constrictingdrugs; nerve compression syndromes; cryoglobulinemia or cold agglutinins; post-frostbite or trench foot; Raynaud’s disease (females more than males).Physical findings: White, cyanotic digit upon exposure to cold or emotional upset;hyperemic upon resumption of circulation.Treatment: Limitation of cold exposure. Stop smoking. Vasodilators. Regionalsympathectomy. LOWER EXTREMITY DEEP VEIN THROMBOSISDEFINITION: Deep venous thrombosis (DVT) is clotting that develops in the deepveins of the calf, thigh, or pelvis.ETIOLOGY: Virchow’s triad of stasis of blood, vessel wall injury, and increasedcoagulability concisely describes the primary etiologic factors that precipitate venousthrombosis. Stasis of blood results from reduced venous return, as occurs inprolonged bed rest, limb paralysis, surgical procedures, and venous valvular 135
    • insufficiency. Vessel wall injury may be due to surgical injury, iatrogeniccatheterization, or blunt/ penetrating trauma. Hypercoagulability may be a primary orsecondary state: its causes include protein deficiencies (protein C, protein S,antithrombin III), malignancy, thrombocytosis, and systemic lupus erythematosus.CLINICAL MANIFESTATIONSHISTORYA majority of cases of DVT are silent and require a high index of suspicion for earlydiagnosis. The patient may have only vague, nonspecific complaints. Localsymptoms may include pain, swelling, or tenderness in the involved extremity. Chestpain and shortness of breath is an infrequent but not rare presentation due to an acutepulmonary embolus (PE) secondary to the DVT.PHYSICAL EXAMINATIONLocalized limb swelling and tenderness can be present. Homans’sign (pain orresistance on passive dorsiflexion of the ankle) may be present and raises clinicalsuspicion but, contrary to past dogma, is a nonspecific finding. The venous occlusionmay become severe and, in are cases, may result in a pale leg with compromisedarterial perfusion (phlegmasia alba dolens).DIFFERENTIAL DIAGNOSIS: DVT must be accurately distinguished from othercauses of a painful, swollen lower extremity. The important disorders in this list aremalignancy, musculoskeletal injury, infections, lymphedema, congestive heartfailure, and ruptured Baker’s cyst.DIAGNOSTIC EVALUATION: A bedside examination with a simple Dopplerultrasound device can be highly accurate in the diagnosis of DVT.TREATMENT: MEDICAL: Outpatient therapy with self – administeredsubcutaneous injections of low-molecular-weight heparin has been shown to be safeand effective.SURGICAL/ INTERVENTIONAL: The need for surgical therapy for DVT is rare.Inferior vena cava filter insertion is indicated in recurrent or progressivethromboembolic disease despite therapeutic anticoagulation. 136
    • DISORDERS OF THE LUNGS AND PULMONARY CIRCULATION PULMONARY EMBOLISMPulmonary embolism is a major cause of morbidity and mortality. Diagnosis can bedifficult and both under-diagnosis and over-diagnosis are common.PathophysiologyPulmonary embolism, pulmonary thrombosis and pulmonary infarction are relatedconditions:Pulmonary embolism results from the obstruction of the pulmonary arterial vessels bythrombus or by material, such as fat or air, originating in some other site.• Pulmonary infarction is the necrosis of a wedge of lung tissue resulting frompulmonary arterial occlusion.Approximately 90% of pulmonary emboli originate in the leg veins. One or more ofthree mechanisms may contribute to their formation:• Venous stasis. Venous stasis may result from prolonged immobilization orincompetent venous valves, possibly as a result of previous thromboembolism.• Blood hypercoagulability. Blood hypercoagulability may be a result of drugtherapy, including the oral contraceptive pill, hormone replacement therapy andsteroids. In addition to this, there are a number of genetic abnormalities thatpredispose to thrombosis.• Injury to the vessel wall. This may occur as a result of local injury or vascularendothelial damage, particularly previous thrombophlebitis.In practice, several mechanisms may coexist. For example, there is an increasedincidence of venous thromboembolism in pregnancy resulting both from venousstasis and a hypercoagulable state. The need to screen patients for possible underlyingsystemic hypercoagulability depends on clinical circumstances. Screening should beconsidered in young patients with no other identifiable predisposing factors, patientswith a family history of thromboembolism and in patients with recurrent thrombosis.The substantial majority of pulmonary emboli originate in the veins from the lowerextremity. However, upper extremity venous thrombosis can also provide an embolic 137
    • source and should be considered, particularly in patients with central venouscatheters, pacing wires or intravenous drug abusers. In addition, the heart itselfshould be considered as a source of embolism in patients with atrial fibrillation,particularly in the presence of right heart failure.Clinical featuresThe nature of the clinical presentation with pulmonary embolism depends on the sizeof the embolus:• A small embolus may present with non-specific features such as dyspnoea ortiredness.• A medium-sized embolus may cause the occlusion of a segment of the pulmonaryarterial tree, causing pulmonary infarction. This may result in• Pleutritic pain, haemoptysis, a low-grade pyrexia and dyspnoea.• Massive pulmonary embolism results from the occlusion of two-thirds or more ofthe pulmonary arterial bed. This causes sudden death, otherwise right-sided failure, alow cardiac output and a rise in venous pressure.The physical signs of pulmonary emboli vary with the size of the embolus. Small andeven medium-sized emboli may be devoid of any abnormal clinical signs. Followingpulmonary infarction, signs of a pleural effusion and pleural rub may be present.Large emboli may cause:• hypotension and shock• tachycardia• cyanosis• elevation of the jugular venous pulse with a prominent V wave• accentuation of the pulmonary component of the second heart sound due topulmonary hypertension• right ventricular third and fourth heart soundsMassive pulmonary embolism should be suspected in any patient who suddenlydevelops the features of shock, syncope, acute dyspnoea or chest pain, particularly if 138
    • the subject has evidence of a venous thrombosis or has been confined to bed duringthe preceding days. Table: Symptoms and signs in 327 patients with pulmonary emboli Symptoms Per Cent Signs Per Cent Chest pain 88 Respirations above 16/min 92 Pleuritic 74 Nonpleuritic 14 Dyspnea 84 Rales (crepitations) 58 Apprehension 59 High pulm. S2 53 Cough 53 Pulse above 100/min 44 Hemoptysis 30 Temperature > 37.8 C 43 Sweats 27 Phlebitis 32 Syncope 13 Gallop (RV S3 or RA S4) 34 Diaphoresis 36 Edema (Pulmonary) 24 Murmur (Tricuspid) 23 Cyanosis (Central) 19Investigations• Chest radiography. This may show features of pulmonary atelectasis or pleuraleffusion which may accompany pulmonary embolism.• Electrocardiogram (ECG). ECG changes accompanying pulmonary embolism areunreliable for diagnostic purposes. In cases of mild to moderate pulmonaryembolism, the ECG is generally normal, except for demonstrating sinus tachycardia.In more severe pulmonary embolism, a number of ECG features may be observed.– S1 Q3 T3 pattern. A narrow Q wave and inverted T wave in lead III,accompanied by an S wave in lead I, all due to changes in the position of the heartcaused by dilatation of the right ventricle and atrium– P pulmonale. right bundle branch block– ‘right ventricular strain’ pattern with T inversion in the leads of V1 to V4– atrial arrhythmias. 139
    • Fig: ECG appearances in pulmonary embolism. Note tall, peaked P waves, partialright bundle branch block (rSr in V1), S in lead I, Q and negative T in III, andinverted T waves in V1 to V3.The differential diagnosis from acute myocardial infarction may be extremelydifficult. The ECG is of considerable value, but the patterns associated with massivepulmonary embolism are often misinterpreted as being those of a combination ofinferior and anteroseptal infarction. The appearance of Q waves and negative Twaves in lead III (but not in lead II) in association with inverted T waves from V1 toV4 strongly suggests pulmonary embolism.• Blood gases. Characteristically pulmonary embolism causes a reduced arterialpO2 due to shunting of blood through underventilated parts of the lung.Simultaneously pCO2 is normal or reduced due to hyperventilation.However, the sensitivity and specificity of these findings is relatively low.• D-dimer. Plasma D-dimer is a useful screening test. The test is sensitive butnot specific. However, a negative D-dimer virtually excludes pulmonary embolismand obviates the needs for additional tests.• Pulmonary scintigraphy. Using radioactive technetium, this is a sensitivetechnique for detecting perfusion abnormalities. 140
    • • Multislice (CT) scanning. This involves the injection of contrast mediumthrough a peripheral vein and enables the right and left pulmonary arteries to bevisualized down to their segmental branches. The test is both sensitive and specific indiagnosing pulmonary emboli and is considered by many as the investigation ofchoice in patients unsuitable for a ventilation—perfusion scan or in whom aventilation—perfusion scan gives equivocal results.• Pulmonary angiography. It is an invasive investigation which carriessignificant risk, particularly in this patient population who may already be criticallyill. The advent of MSCT has largely superceded the need for pulmonary angiography.• Venous ultrasonography.• Echocardiography: Echocardiography is of value as a means of assessingpressure overload on the right ventricle which accompanies massive pulmonaryembolism.ManagementThere are two major objectives in management:• The prevention of further thromboembolism• In severe cases, the detection and relief of right heart failure.AnticoagulationIn the majority of patients the haemodynamic consequences of pulmonary emboli arenot severe. The primary objective of treatment is the prevention of further emboli.Patients are treated initially with intravenous heparin, adjusted according to thepatient’s activated partial thromboplastin time. Warfarin therapy is commenced andheparin discontinued after 5—7 days. Heparin should be maintained for at least 2days after achieving a therapeutic international normalized ratio (INR).The recent introduction of low molecular weight heparins has substantially replacedthe use of conventional heparin. Low molecular weight heparins carry severaladvantages.The target INR therapeutic range for the management of pulmonary embolism isgenerally 2.0—3.0. The duration of anticoagulation varies with clinicalcircumstances. If a predisposing factor can be identified and this factor no longer 141
    • exists, treatment for 3 months may be adequate. If no predisposing factor can beidentified, a minimum of 6 months anticoagulation is generally recommended. Inpatients with recurrent thromboembolism, lifelong anticoagulation is recommended.Similarly, in patients with a defined hypercoagulable state, lifelong anticoagulationmay be necessaryIn exceptional patients who have recurrent pulmonary emboli while on warfarin, aninferior vena caval filter device can be considered. This device, insertedpercutaneously via a catheter, traps clots preventing migration to the lungs.Management of massive pulmonary embolismIn patients with massive pulmonary embolism, sufficient to cause severehaemodynamic compromise, thrombolytic therapy should be considered. Unlikethrombolytic treatment of acute myocardial infarction, there is no evidence-basedconsensus as to which patients should be treated. However, there is generalagreement that patients with systemic hypotension should receive thrombolytictherapy, because the prognosis of this group if left untreated is so poor.General management and pain reliefOpiates such as diamorphine are appropriate, but care is needed in hypotensivepatients. Hypoxaemia is likely and high concentrations of oxygen (at least 40%)should be administered. If right-sided pressure should fall, it may become necessaryto give intravenous fluids to maintain cardiac output.AnticoagulationThe patient should be heparinized to prevent further embolism. Therapy should beinitiated with a bolus of 5000—10 000 units, followed by a maintenance infusion of1000 units/h, adjusted according to the activated partial thromboplastin time (APTT).A low molecular weight heparin, such as enoxaparin 1.5 mg/kg every 24 h given bysubcutaneous injection can be used as an alternative.ThrombolysisIn patients with severe haemodynamic compromise thrombolytic therapy should begiven to dissolve the embolus A loading dose of 250 000 units of streptokinase 142
    • should be given over 30 mm, followed by a maintenance infusion of 100 000 unitshourly for 23 hours.Embolectomy: Pulmonary embolectomy is rarely undertaken. PULMONARY HYPERTENSIONThe pulmonary circulation is a low pressure system (16/8 in men, 20/10 in women).Pulmonary hypertension exists when the systolic pressure exceeds 30 mmHg or meanpressure > 25 mmHg. There are two types of pulmonary hypertension:• Pulmonary hypertension is most commonly secondary to other cardiac or lungdisease - this is termed secondary pulmonary hypertension.• Less commonly, pulmonary hypertension occurs in isolation, unrelated to otherheart and lung problems — this is termed primary pulmonary hypertension.Causes of secondary pulmonary hypertensionPulmonary arterial hypertension (greater than 30/15 mmHg) may result from:• an increase in pulmonary capillary pressure• an increase in pulmonary blood flow• an increase in pulmonary vascular resistance.Elevated pulmonary capillary pressurePassive pulmonary hypertension due to a raised pulmonary capillary pressure occursin all conditions in which the left atrial pressure rises, such as mitral stenosis and leftventricular failure. The pulmonary artery pressure rises in proportion to thepulmonary capillary pressure.Increased pulmonary blood flowPulmonary hypertension due to increased flow develops in disorders in which thereare left-to-right shunts. These include:• ventricular septal defects (VSD)• persistent ductus arteriosus (PDA)• atrial septal defect (ASD). 143
    • Causes of increased pulmonary vascular resistanceCor pulmonaleChronic thromboembolismEisenmenger’s syndromeCollagen vascular diseasesPrimary pulmonary hypertensionMechanism of increased pulmonary vascular resistance:• Pulmonary vasoconstriction. Blockage of the pulmonary arteries or arterioles by thrombosis and embolism asin thromboembolism and schistosomiasis.• Arterial medial hypertrophy:Combinations of the three mechanisms are common. In mitral stenosis for examplethe initial phase of passive pulmonary hypertension is often complicated byvasoconstriction and by the obliterative changes of pulmonary embolism. In manycases of ventricular septal defect both high blood flow and pulmonary vasculardisease contribute to pulmonary hypertension. In emphysema, obliteration of thevascular bed and hypoxia are contributory factors. 144
    • Clinical features of pulmonary hypertensionIndependent of causation certain clinical features are characteristic of severepulmonary hypertension. The symptoms include• Dyspnoea. Fatigue. Syncope. Haemoptysis. chest pain. symptoms of right-sided cardiac failure. Summary: Important causes of pulmonary hypertension- Mitral stenosis- Recurrent pulmonary emboli- Left ventricular failure- Schistosomiasis- Parenchymal lung disease- Congenital heart disease, L to R shunt (Eisenmenger syndrome)- Primary pulmonary hypertensionAbnormal features on clinical examination may include:• elevation of the jugular venous pulse with a prominent ‘a’ wave• features of tricuspid regurgitation• a forceful right ventricular heave along the left sternal edge• a right ventricular fourth-heart sound at the lower left sternal edge• a loud pulmonary component to the second sound, which may be followed by anearly diastolic murmur of pulmonary regurgitation (Graham Steel murmur).Investigation: The chest radiograph may show enlargement of the proximalpulmonary arteries, right ventricle and right atrium. The peripheral lung fields appearoligaemic.• The ECG demonstrates features of right ventricular hypertrophy:— tall peaked P waves in lead II due to right atrial enlargement— right axis deviation, a predominant R wave in lead VI— inverted T waves in leads VI—V3 145
    • ManagementBoth management and prognosis of pulmonary arterial hypertension depend upon itsaetiology and on its severity Passive pulmonary hypertension responds well if theunderlying disorder can be corrected (e.g. mitral stenosis) Pulmonary hypertensiondue to high pulmonary arterial flow can usually be reversed by the correction of theunderlying congenital abnormality Increased pulmonary arterial resistance due tovasoconstriction can often be diminished by relieving hypoxia or by the successfultreatment of mitral valve disease.When pulmonary hypertension is due to severe pulmonary vascular disease as in theEisenmenger syndrome, the prognosis is poor and life is usually sustained for only afew years In these cases, cardiac failure is progressive in spite of treatment and theonly hope may lie in heart—lung transplantation Primary (‘unexplained’) pulmonary hypertensionPulmonary hypertension is said to be primary when the aetiology cannot bedetermined. The pathology is complex and poorly understood. The diagnosis is madeby exclusion in patients found to have the clinical features of pulmonaryhypertension. Lung biopsy can aid diagnosis, but is potentially hazardous.The condition, which is rare, is most common in young women. The onset of thedisease is insidious The first symptoms are usually fatigue and exertional dyspnoeaChest pain syncope and right heart failure may also occur By the time symptomsoccur, the disease is generally advanced with severe pulmonary hypertensionPhysical findings: A right ventricular lift and accentuation of the pulmonarycomponent of the second sound may be evident. As the disease progresses, manypatients develop tricuspid regurgitation and right heart failure.Echocardiography is a particularly important diagnostic tool. The right atrium andright ventricle are generally dilated and tricuspid regurgitation often present. Theright ventricular to right atrial pressure gradient can be calculated from the velocity ofthe regurgitant jet. Extensive additional investigations are then likely to be required toexclude secondary causes of pulmonary hypertension. 146
    • ManagementA number of therapies should be considered:• Thrombosis may contribute to the progression of hypertension and anticoagulantsare recommended; oral contraceptives and pregnancy must be avoided.• Vasodilator therapy may prove of value in some patients. Patients may be given atrial of an oral calcium channel blocker. Amlodipine is commonly chosen, on accountof its relative lack of negative inotropic effects.• Phosphodiesterase inhibitors: Sildenafil is a selective inhibitor of cGMP-specificphosphodiesterase and hence potentiates vasodilatation. It is very valuable in primarypulmonary hypertension. Pulmonary Heart Disease (Cor Pulmonale)Definition: Cor pulmonale is right ventricular hypertrophy or dilatation secondary topulmonary hypertension resulting from diseases affecting lung vessels or lungparenchyma and not from left heart lesion.The prevalence of pulmonary heart disease varies greatly between one geographicalarea and another. The commonest cause of cor pulmonale is chronic obstructivepulmonary disease (COPD) and this is reflected in its prevalence. There is abundantevidence that heavy cigarette smoking and air pollution are major factors in theproduction of COPD.Causes and types of Cor PulmonaleI. Acute cor pulmonale: A) Massive pulmonary embolism. B) Extensive lung disease: Spontaneous pneumothorax. Massive atelectasis.II. Subacute cor pulmonale A) Recurrent showers of minute pulmonary embolization. B) Lymphangitis carcinomatosis of lung. C) Collagen vascular disorders (SLE, polyarteritis nodosa). 147
    • III. Chronic cor pulmonale A) Vascular cor pulmonale: (non hypoxic) Schistosomal cor pulmonale Primary pulmonary hypertension (B) Parenchymatous cor pulmonale (Hypoxic) Obstructive airway disease Extensive lung fibrosis, Bronchiectasis, Interstitial fibrosis of the lung Defective movement of chest wall Schistosomal cor pulmonaleSchistosomal cor pulmonale is a chronic vascular cor pulmonale due to widespreadaffection of the small pulmonary arterioles leading to wide spread obliteration, withlittle or no involvement of lung parenchyma.Mechanism of pulmonary hypertension in schistosomal cor pulmonale:- Obliterative: related to heavy embolization of schistosoma ova to the lungs.- Vasospastic:- Increased pulmonary blood flow due to various vascular shunts.Clinical features:- History of bilharziasis and signs of bilharzial affection of other organs (e.g. hepatosplenomegaly).- Signs of pulmonary hypertension and right ventricular hypertrophy.- Often there is marked dilatation of the pulmonary artery causing pulmonary artery aneurysm and even pulmonary regurgitation (Graham Steel murmur).Treatment: see pulmonary hypertension. 148
    • DISEASES OF THE PERICARDIUMPericardial disease, which may be acute or chronic, is usually associated either with ageneralized disorder or with pulmonary disease. ACUTE PERICARDITISCauses of pericarditisInfective: Viral - Coxsackie B, influenza, measles, mumps, chickenpox, humanimmunodeficiency virus. Pyogenic. Fungal. Tuberculous.Connective tissue disorder: Rheumatic fever. Rheumatoid arthritis. Systemic lupuserythematosus, Polyarteritis. Scleroderma. AutoimmuneSarcoidAcute myocardial infarctionPost-myocardial infarction (Dressler) syndromePost-pericardiotomy syndromeNeoplastic invasionMetabolic and endocrine: Uraemia. Gout.TraumaClinical featuresChest pain is the commonest symptom of acute pericarditis and is characterized asfollows: • Its distribution simulates that of acute myocardial infarction, being centraland sometimes radiating to the shoulder and upper arm. The pain may be most severein the xiphisternal or epigastric regions.• It is often sharp and severe, but may be aching or oppressive.• Unlike ischaemic cardiac pain, pericardial pain is commonly accentuated byinspiration, by movement and by lying flat.The most definitive sign of pericarditis is a pericardial rub, although this is notalways present. A to-and-fro scratchy or grating noise may be heard in systole, mid-diastole and presystole, or in only one of these phases. 149
    • Investigations: Electrocardiogram (ECG): In the early stages, the ECG usuallyshows widespread ST elevation with the ST segment concave upwards.• Echocardiography is frequently of value in the detection of a pericardial effusion,but the absence of a pericardial effusion does not exclude the diagnosis of acutepericarditis.• Raised C-reactive protein (CRP). Autoimmune markers may be abnormal in casesof pericarditis associated with connective tissue diseases.Differential diagnosis: Acute pericarditis is most likely to be confused with:• Acute myocardial infarction.• Pneumothorax. • Pleurisy.Etiological diagnosis- Viral pericarditis should be suspected if there is a history of an upperrespiratory infection and fever preceding the chest pain.- Tuberculous pericarditis may be difficult to diagnose, because there is oftenno evidence of either pulmonary or miliary infection. Usually, however, there is ahistory of malaise and weight loss for some weeks prior to the pericarditis.Tuberculosis is unlikely if tuberculin skin tests are negative. If necessary thediagnosis may be confirmed by pericardial aspiration or biopsy.- In pericarditis due to staphylococci, streptococci or pneumococci, there isusually infection in the lungs or elsewhere in the body.- In rheumatic fever, there is accompanying evidence of the rheumatic processas well as of myocarditis and endocarditis. In pericarditis due to hypersensitivityor autoimmunity, there is no preceding respiratory infection but there is often ahistory of similar episodes in the past.Acute pericarditis may also occur in patients with acquired immune deficiencysyndrome (AIDS).TreatmentThis consists of the symptomatic relief of pain with anti-inflammatory analgesics andthe treatment of the underlying cause when this is possible. 150
    • Bacterial pericarditis should be treated with the appropriate antibiotics; surgicalremoval of pericardial pus may be necessary. PERICARDIAL EFFUSIONPericardial effusion may result from: Transudation (in cardiac failure), exudation of serous fluid or pus (in pericarditis) Blood (from trauma or malignant disease).It is also a feature of myxoedema. The hydropericardium of cardiac failure causesfew, if any, symptoms, although it may cause compression of the lungs and reducethe vital capacity. Pericardial effusion due to other causes my produce pain andpericardial tamponade.Clinical featuresHeart sounds are generally soft on auscultation. Pericardial friction rubs areuncommon in chronic effusions. If the effusion is constricting, there may beassociated signs of cardiac tamponade (see below).InvestigationsThe chest radiograph is valuable in diagnosis. When there is a considerable effusion,the cardiac silhouette is enlarged and rounded, with loss of the normal demarcationbetween the cardiac chambers. Similar abnormalities may be seen in some cases ofcardiac failure, but the presence of a very large heart shadow in the absence ofpulmonary vascular congestion makes the diagnosis of pericardial effusion likely.• Pericardial effusion produces low-voltage ECG complexes which may varyconsiderably in amplitude from cycle to cycle (‘electrical alternans’), reflectingchanges in the position of the heart within the pericardial effusion.• Echocardiography is the most useful diagnostic method.Treatment: Paracentesis may occasionally be required for diagnostic purposes, e.g.to identify a causative organism. No specific treatment is required for a pericardialeffusion unless there is tamponade. Otherwise treatment is of the underlyingcondition. 151
    • PERICARDIAL TAMPONADEProbably the commonest causes are neoplasm and idiopathic or viral pericarditis, butit may develop in such conditions as uraemia, myocardial infarction, and after atraumatic cardiac catheterization, perforation by a pacing wire, cardiac surgery andchest injury.The inability of the ventricles to fill during diastole leads to raised diastolic pressuresin right and left ventricles, an increase in systemic and pulmonary venous pressures,and a fall in cardiac output.Clinical featuresClinical features include: • Sinus tachycardia• Elevation of jugular venous pulse. A further rise may occur during inspiration(Kussmaul’s sign).• Hypotension and shock in severe cases.• Pulsus paradoxus — variation in systemic blood pressure in relation to therespiratory cycle. In pulsus paradoxus, there is a respiratory variation in pulseamplitude, with a decrease on inspiration.InvestigationsEchocardiography is the most important investigation in pericardial tamponade.Echocardiographic findings include:• Right and left atrial diastolic collapse• Right ventricular diastolic collapse• Inspiratory increase in tricuspid flowManagement of cardiac tamponade: This is an emergency.Pericardial aspiration - Samples of aspirate should be sent to microbiology, cytology. PERICARDIAL CONSTRICTION (CONSTRICTIVE PERICARDITIS)Constriction of the heart by a fibrosed or calcified pericardium is relativelyuncommon. In most patients, no identifiable cause can be found, although in some 152
    • communities a tuberculous infection is responsible for the majority of cases.Constriction can also be a late complication of other types of infection, neoplasticinvasion and intrapericardial haemorrhage, including previous cardiac surgery.Adequate filling of the ventricles during diastole is prevented by thick, fibrous and,often, calcified pericardium.Clinical features and diagnosisThe inability of the ventricles to distend during diastole leads to an increase indiastolic pressure and to a consequent rise in pressure in the left and right atria and inboth pulmonary and systemic veins. Symptoms resemble those of right- sided cardiacfailure. The presenting complaint is often that of abdominal swelling due to ascites,but dyspnoea and ankle swelling are also common. The clinical features are asfollows: Sinus tachycardia is usually present, but atrial fibrillation develops in theadvanced case. The neck veins are grossly engorged and show two characteristic features; a rapid‘y’ descent and an increase in pressure on inspiration. There is nearly always an early diastolic sound heard best at the lower end of thesternum. The liver is enlarged and often tender. In contrast with the severity of the ascites,peripheral oedema is comparatively slight.Investigations: One of the most characteristic features of pericardial constriction is ashell- like rim of calcified pericardium, which is particularly well seen in lateralradiographs of the heart. Computed tomography (CT) and magnetic resonanceimaging (MRI) are of value, demonstrating thickening of the pericardium in almostall cases.The ECG is not diagnostic, but usually shows low-voltage QRS complexes associatedwith flattened or slightly inverted T waves.• Raised left ventricular diastolic, left atrial, pulmonary arterial, right ventriculardiastolic and right atrial pressures. 153
    • • The right ventricular pressure pulse shows an early diastolic dip followed by aplateau (Fig.).Fig: Characteristic RV pressure pulse in pericardialconstriction. Note early diastolic dip, followedby a plateau.Differential diagnosisA number of other disorders should be considered in the differential diagnosis:• Restrictive cardiomyopathy. • Other causes of heart failure• Pulmonary disease and cor pulmonale• Tricuspid stenosis and regurgitation• Superior vena cava obstruction. • Hepatic disease.Features of constrictive pericarditis and restrictive cardiomyopathy Constrictive pericarditis Restrictive cardiomyopathyS 3 gallop Absent May be presentPalpable apical impulse Absent May be presentPericardial calcification Frequently present May be presentCT / MRI findings Thickened pericardium Normal pericardiumRV and LV pressures Usually equal LV> RVRate of LV filling Rapid early diastolic Reduced early diastolic filling filling CARDIOMYOPATHY AND MYOCARDITISThe terms myocarditis and cardiomyopathy are reserved for those relativelyuncommon types of myocardial disease which cannot be attributed to coronaryatherosclerosis, congenital or valvular heart disease or hypertension. MYOCARDITISCauses of myocarditis 154
    • Infective: Viruses — Coxsackie B, cytomegalovirus, infectious mononucleosis,human immunodeficiency virusMycoplasma. Bacteria, Spirochetes. Rickettsiae. Fungi, Parasites and protozoaRadiation. Drugs — Sulphonamides, doxorubicin, lithium, emetine,cyclophosphamide. Heavy metals. Hypersensitivity states. Insect stingsClinical features• Chest pain is common, but usually attributable to associated pericarditis.• Heart rate: Tachycardia.• Heart failure: The symptoms and signs of left and right cardiac failure may develop,with dyspnoea, gallop rhythm, cardiac enlargement and murmurs due to dilatation ofthe ventricles.Investigations: Echocardiography and radionuclide imaging. ECG. Myocardialbiopsy.Management: There is no specific treatment. Therapy is primarily supportive,treating the complications of heart failure and arrhythmias if they occur. Bed rest isadvisable, followed by a period of restricted activity for approximately 6 months.H IV: Clinically apparent cardiac involvement occurs in about 10% of patients withacquired immune deficiency syndrome (AIDS). CARDIOMYOPATHYThe term cardiomyopathy refers to a disease process involving heart muscle.Cardiomyopathies are divided into primary and secondary:• Primary cardiomyopathy. Disease confined to heart muscle and not arising from anyother identifiable disease processes.• Secondary cardiomyopathy. Heart muscle diseases arising as part of a moregeneralized disorder, which closely resemble the clinical characteristics of a primarycardiomyopathy. 155
    • The commonest cause of heart muscle disease is damage as a result of myocardialinfarction. This is referred to as ischaemic cardiomyopathy, but differs from the truecardiomyopathies in the focal nature of the myocardial abnormality.Functional categoriesThree types of functional impairment are observed in patients with cardiomyopathy: Dilated. The ventricles are dilated with impaired function. Hypertrophic. The left ventricle is inappropriately thickened, but contractilefunction is preserved. Restrictive. Diastolic filling is impaired.Systemic disorders causing secondary cardiomyopathyConnective tissue disorders (systemic Lupus erythematosus, scleroderma andPolyarteritis). Amyloidosis. SarcoidosisNeuromuscular diseases (Friedreich’s ataxia, progressive muscular dystrophy andmyotonic dystrophy). Haemochromatosis. Glycogen storage diseases Dilated cardiomyopathySome causes of dilated cardiomyopathyInfection: Viral myocarditis. Human immunodeficiency virusToxins and drugs: EthanolNutritional and related deficiencies: Thiamine deficiencyPregnancyClinical features: Dyspnea, tachycardia, signs of heart failure, mitral and tricuspidincompetence and gallop.Treatment: Management is the general management of heart failure. HYPERTROPHIC CARDIOMYOPATHY In this condition, there is massive hypertrophy of the ventricles. The hypertrophyarises in the absence of any obvious cause that is in the absence of underlying aorticstenosis or hypertension. The ventricular septum is often the site of the mostconspicuous hypertrophy, which may obstruct the left ventricular outflow tract 156
    • (hypertrophic obstructive cardiomyopathy). An outflow gradient is present inapproximately one-quarter of patients with hypertrophic cardiomyopathy.Pathogenesis: Disorganization of the muscle bundles (myofibrillar disarray).Genetics: In about 50% of cases autosomal dominant inheritance is present.Clinical features: Symptoms are often similar to those that occur in aortic stenosis,including dyspnoea, angina and syncope. Arrhythmias are common and there is ahigh risk of sudden death.Physical signs include: In Patients with left ventricular outflow obstruction, evidence of an ejection systolicmurmur, which is best heard at the apex or the left sternal border. The murmur ischaracteristically labile and increases with a Valsalva maneuver. Third and fourth heart sounds which are common.Investigations- ECG. The ECG is commonly abnormal. It may show ST/T wave abnormalities orcriteria of left ventricular hypertrophy.- Echocardiographic features of hypertrophic cardiomyopathy Non-concentric hypertrophy with asymmetrical hypertrophy of the septum(ASH); and the obliteration of the ventricular cavity during systole In cases with a left ventricular gradient, systolic anterior movement of the mitralvalve (SAM) and mid-systolic closure of the aortic valve may be evident. Doppler echo can be used to measure any intraventricular pressure gradient. Abnormal diastolic relaxation. The presence of mitral regurgitationDifferential diagnosisThe murmur of obstructive cardiomyopathy has usually to be differentiated fromother types of left ventricular outflow obstruction, most particularly aortic stenosis:Factors favoring hypertrophic cardiomyopathy over athlete’s heart include: unusual and unequal distribution of hypertrophy (e.g. septal hypertrophy) decreased left ventricular cavity size 157
    •  left atrial enlargement abnormal ECG; although ECG abnormalities can also be seen in trained athletes family history of hypertrophic cardiomyopathy the persistence of hypertrophy on detraining.Management- In patients with refractory symptoms, surgical resection of part of theinterventricular septum is occasionally indicated.- An alternative approach is septal ablation. An injection of phenol is given directlyinto the septal branch of the left anterior descending coronary artery. This results in‘controlled infarction’ of the septum thereby reducing outflow obstruction.- Some patients appear to derive benefit from dual-chamber pacing.- Patients thought to be at high risk of sudden cardiac death should be consideredfor an implantable cardioverter defibrillator (ICD). Restrictive and infiltrative cardiomyopathiesRestrictive cardiomyopathy is the least common of the three major functionalcategories of cardiomyopathy (dilated, hypertrophic and restrictive). In restrictivecardiomyopathy, the ventricles are abnormally stiff and impede ventricular filling,with the result that there is abnormal diastolic function. Systolic function, by contrast,may remain normal. Cardiac TumorsCardiac tumors are rare. The commonest is the myxoma which occurs mostfrequently in the left atrium. Because its position may vary with posture, transient orcomplete obstruction of the mitral valve may result.The hemodynamic effects of left atrial myxoma usually resemble those of mitralstenosis. The tumor may also be responsible for embolic phenomena, and canproduce constitutional effects such as fever, weight loss, anemia, raised plasmaviscosity and ESR and abnormal serum protein level.The diagnosis is made by echocardiography and the treatment is by surgical excision. 158
    • Questions and Answers asked in the Exam of the Medical Rounds- Manifestations of R. heart failure - Kussmaul sign inCongested neck veins 1- constrictive pericarditisEnlarged tender liver 2- restrictive cardiomyopathyLower limb edema 3- severe Rt, side heart failureR. ventricular gallop 4- pericardial effusion with tamponade- Manifestations of L. heart failure - Causes of atrial fibrillationBasal crepitations Mitral valve diseaseL. ventricular gallop coronary heart diseaseOrthopnea HypertensionParoxysmal nocturnal dyspnea hyperthyroidism Neck Veins: Constrictive pericarditis Systolic pulsations in tricuspid ASDincompetence and atrial fibrillation. - Complications of atrial fibrillationGiant prominent ‘a’ wave in tricuspid Thromboembolic (embolus)stenosis and RV hypertrophy as in Decreased cardiac performancepulmonary stenosis and pulmonary - Diagnosis of Infective endocarditishypertension. Canon ‘a’ wave in Blood culturecomplete heart block. vegetations by ECHO - Clubbing causes - Aortic dissectionCardiac causes Severe lancinating chest painCyanotic heart diseases Unequal blood pressure in both armsInfective endocarditis (due to closure of LT subclavian artery)Respiratory - Valvular heart diseaseSupportive lung disease (bronchiectasis, - Mitral stenosis:lung abscess) Signs:- Snappy S1, mid diastolicBronchogenic carcinoma rumbling murmur, diastolic thrill, O.S.BUT (bronchial asthma, TB) never causeclubbing - Aortic regurgitationBlue clubbing: congenital heart disease Soft blowing early diastolic murmurPale clubbing: Infective endocarditis propagated to the apex - Myocardial infarctionChest pain compressing - Aortic stenosisSevere radiation to the arm and back Harsh ejection systolic murmurSyncope, sweating Systolic thrillAuscultation S4 or nothing Absent A2- Congested non pulsating neck veins: Sustained apexSVC obstruction Plateau pulseCauses : wide fixed splitting of S2: ASD - Signs of DVT: - Tricuspid regurgitation1- one calf larger than the other Pansystolic murmur increases in2- tender calf muscles inspiration3- Homans sign: pain in dorsiflexion of Systolic pulse in the liver 159
    • ankle Systolic neck veins - Rheumatic fever - Eisenmenger syndrome occurs in allJohn’s criteria major and minor except:A-Major criteria a- Large VSD- Myocarditis (L. heart failure- gallop- b- Large ASDarrhythmia) c- PDA- Endocarditis (mitral regurgitation – d- Fallot`s tetralogyaortic regurgitation)- Pericarditis. (How to diagnose - Epigastric pulsations in all except:pericarditis by ECHO: by presence of a-portal hypertensionpericardial effusion) b- aortic aneurysmB-Minor criteria c-congestive heart failure- Clinical (fever, arthralgia, history of d- Rt ventricular enlargementprevious tonsillitis 1-3 wks, presence ofRh. valve lesion) - In AF all is present except:- Lab. (Increased CRP, ESR, prolonged a. absent a wavePR) b. S4 c. S1 of variable intensity- 60 year male patient with hypertension d. Systolic neck venous pulsationpresented with BP 200/100 mmHg, e. Irregular irregularity in the pulsesevere chest pain, unequal pulse:Most probable diagnosis is dissecting - In pulmonary hypertension all is presentaortic aneurysm except: - Pulsus alternans occurs in heart a. systolic thrill on the pulmonary areafailure. b. S2 close (narrow) splitting- Paradoxical pulse occurs in pericardial c. Diastolic shocktamponade, constrictive pericarditis. d. Ejection systolic murmur MCQs - AF is caused by all except:- Accentuated first heart sound in all a. Ischemic heart disease except: b. Thyrotoxicosisa- Short P-R interval c. Mitral valve diseaseb- Increase cardiac output d. Cor pulmonalec- Mitral stenosisd- Myocarditis - Edema in congestive heart failure occur in all except: a- Peri-orbital b- Ankle c- Sacrum d- External Genitalia 160