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Cardiomyopathies
This document discusses dilated cardiomyopathy (DCM), the most common type of cardiomyopathy. It provides details on: 1) The causes, symptoms, signs, diagnostic tests and goals of treatment for DCM. The mainstay of therapy includes vasodilators, digoxin and diuretics. 2) The morphological and microscopic features of DCM which involve enlargement and spherical dilation of the heart chambers. 3) Disease progression can lead to marked left ventricular dilatation and circulatory failure if left untreated. Management aims to relieve symptoms and slow progression.
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Cardiomyopathies
- 1. Dr Tarun Bhatnagar ConsultantCardiac Anaesthesiologist dr.tarunbhatnagar@yahoo.co.in
- 2. WHO in 1995 defined Cardiomyopathies as diseases of myocardium associated with cardiac dysfunction Types Dilated Cardiomyopathy(DCM) Hypertrophic Cardiomyopathy(HCM) Restrictive Cardiomyopathy(RCM) Arrythmogenic RVCardiomyopathy(ARVC)
- 4. DCM is most common of all CMs(60%) Aetiology -Idiopathic (50%) -Myocarditis (9%) -Ischemic (7%) -Others-Viral, Peripartum, Substance abuse etc Morphologically Enlargement of RV & LV cavities without an increase in ventricular septal or free wall thickness → spherical shape & dilatation of heart → Displacement of papillary muscles → Regurgitant lesions despite valve leaflets being normal
- 5. Medslides.com 5 of 48
- 6. Microscopically –Patchy & diffuse loss of tissue with interstistial fibrosis & scarring Systolic Dysfunction>>> Diastolic dysfunction SV is initially maintained by ↑↑ EDV With disease progression→Marked LV dilatation with normal or thin wall →↑ Wall stress + Valvular Regurgitation →Overt Circulatory Failure
- 7. Symptoms -Typically pts c/o months of fatigue, weakness, reduced exercise tolerance due to CHF -May also present as a Stroke, Arrythmia or Sudden Death Physical Signs -Tachycardia -pulsus alternans -Jugular venous distension -Murmurs of AV valve regurgitation -Gallop heart sounds
- 8. CXR- Cardiomegaly , Pulmonary venous congestion ECG- Normal or low QRS voltage , abn axis, non specific ST seg abnormalities, LV hypertrophy, conduction defects, AF, Non sustained VT 2D Echo Coronary Angiography -usually normal coronaries -coronary vasodilatation is impaired by ↑ LV filling pressures -distinguishes b/w Ischemic & Idiopathic DCM Endomyocardial Biopsy rarely valuable to identify the aetiology
- 11. Aim of treatment -Manage the symptoms -Reduce the progression of disease -Prevent Complications Mainstay of Therapy Vasodilators + Digoxin + Diuretics
- 12. ACE Inhibitors -Indicated for all patients - Reduce symptoms & improve effort tolerance - Suppress ventricular remodelling & endothelial dysfunction -Reduce CV mortality Milrinone -Selective PDE-3 inhibitor -may improve quality of life but doesn’t affect mortality -rarely adm in chronic situations
- 13. Spironolactone used along with ACE Inhibitors has shown to reduce mortality by 30% in a large double blind randomized trial Digoxin clinically beneficial as reaffirmed by two large trials in adults β Blockers untill recently contraindicated but recent studies show that they not only provide symptomatic improvement but substantial reduction in sudden death in NYHA class II & III HF pts
- 14. Amiodarone -High grade ventricular arrythmias (Sustained VT or VF) are common in DCM→↑ risk of SCD -Preferred antiarrythmic agent as it has least negative inotropic effect & proarrythmogenic potential -Implantable Defibrillators are used for refractory arrythmias Anticoagulants -indicated for pts with moderate ventricular dilatation+mod-severe systolic dysfunction -H/O stroke , AF or evidence of Intracardiac thrombus
- 15. Dual Chamber Pacing Cardiomyoplasty LV Assist Devices improved pts sufficiently to avoid transplant or enable later transplant Cardiac Transplantation has substantially prolonged survival in DCM pts with 5 yr survival rate of 78%
- 16. Cardiac procedures which DCM pts undergo -Correction of AV valve insufficiency -Placement of ICD device -LV Assist device placement -Allograft Transplantation Goals of Anaesthetic Mx - Reduction of afterload -Optimizing preload -Minimize myocardial depression DCM pts are extremely sensitive to cardiac depressant anaesthetic drugs
- 17. Fentanyl-(30u/kg )provides excellent anaesthesia & hemodynamics in pts with EF<0.3 Remifentanyl- assoc with severe hypotension & bradycardia ,therefore unsuitable in low EF pts Etomidate-least effect on cardiac contractility in pts undergoing cardiac transplant Ketamine-excellent choice in combination with fentanyl for induction in pts with severe myocardial depression Propofol-causes CV depression due to inhibition of sympathomimetic activity & vasodilatation Volatile agents-Desflurane with lowest BG partition coefficient may allow some benefit for rapid induction, rapid recovery from anaesthesia & early extubation
- 18. Invasive hemodynamic monitoring -Mandatory in pts with DCM undergoing surgery -Physical s/s may not accurately reflect physiological parameters -Pts with Implanted defibrillators have severely depressed cardiac function but are routinely managed without a PAC Hemodynamic Instability -managed by low dose of inotrope & vasodilator
- 19. Afterload reduction -improves regional & global indices of ventricular relaxation & EF during anaesthesia when myocardial depression may be significant -it also reduces valvular regurgitation & volumes Patients on Amiodarone on long term basis can interact with anaesthetic agents & further reduce contractility & conduction-requires careful titration Arrythmogenic factors – Hypokalemia, Hypomagnesemia, & Sympathatic activation should be monitored & corrected
- 20. Hypertrophic Obstructive Cardiomyopathy(HOCM) Idiopathic Hypertrophic subaortic stenosis(IHSS) Assymetric Septal Hypertrophy M/c genetic cardiac disease Prevalance in adults-0.2% Primary myocardial abnormality with sarcomeric disarray & assymetric LV hypertrophy
- 21. Massive left ventricular hypertrophy,mainly confined to the septum Histopathology showing significant myofiber disarray and interstitial fibrosis
- 22. Causes: Inherited, acquired, unknown Autosomal dominant inheritance pattern >450 mutations in 13 cardiac sarcomere & myofilament-related genes identified ?? Role for environmental factors
- 23. Hypertrophic cardiomyopathy: variants Hypertrophiccardiomyopathy morphology exhibits heterogeneity. The mostcommon variant is assymetric septal hypertrophy involving the entire septum
- 24. Subaortic Obstruction Diastolic Dysfunction Myocardial Ischemia Mitral Regurgitation Arrythmias
- 25. Cause -Assymetrical Septal Myocardial Hypertrophy Unlike Aortic stenosis hypertrophy begets pressure gradient , not the other way around Wide spectrum of severity of obstruction ch by Variability- absent to critically severe Dynamic nature - depends on contractility & loading conditions Timing - begins early & peaks variably Location -subaortic
- 26. Subaortic Obstruction Cause-Hypertrophic septum encroaching on the systolic outflow tract Bounded-Anteriorly by IVS & Posteriorly by AML Effect-Systolic anterior motion(SAM) of AML → accentuating obstruction Mechanism of SAM Thickened IVS→Restricted LVOT → ejection of blood at a higher velocity closer to the AML → Drawing of AML closure towards the hypertrophied septum due to the venturi effect during LV systole→ Dynamic LVOT obstruction
- 28. Factors aggravating SAM & producing Dynamic Obstruction- -↑ Contractility -↓ Afterload (Aortic outflow resistance) -↓ Preload (End diastolic volume) Therapeutically Myocardial depression, Vasoconstriction & Volume overloading should minimize obstruction & augment forward flow LVOT gradient ≥ 30mmHg assoc with physiologic & prognostic importance LVOTO is assoc with ↑ wall stress, myocardial ischemia, cell death & eventually fibrosis→VT /VF Dynamic LVOTO may also occur in Cardiac tamponade or Acute MI
- 29. Hypertrophied & disorganizedmyocytes with ↑CoT Impaired relaxation+ ↑ Chamber stiffness Diastolic Dysfunction→↓ rate of rapid ventricular filling ↑ atrial systolic filling ↑ Filling pressures & pulmonary congestion
- 30. Myocardial Ischemia ◦ Often occurs without atherosclerotic coronary artery disease ◦ Postulated mechanisms Abnormally small and partially obliterated intramural coronary arteries as a result of hypertrophy Inadequate number of capillaries for the degree of LV mass
- 31. Dyspnea onexertion (90%) Angina (70-80%) Syncope (20%) Sudden cardiac death
- 32. ECG-↑ QRS voltage, ST-T changes, Axis deviation, LV Hypertrophy +strain pattern CXR-Lt atrial enlargement or normal Echo Invasive Cardiac Cath- indicated for suspected CAD or Severe mitral valve disease - shows LV pressure gradient,↓ ventricular volume, ↑ LVEDP
- 36. Pharmacological Surgical Non Surgical Alternatives Implantable Cardioverter Defibrillator(ICD) Cardiac Transplantation
- 37. β Blockers- mainstay of therapy relieves symptoms of exercise intolerance & dyspnoea assoc with CHF by- negative inotropic effect -HR reduction -lower myocardial O2 demand - longer diastolic filling times CCB-Verapamil is indicated if β Blockers not tolerated or ineffective -it improves diastolc function & ventricular relaxation causing improved filling decreased obstructive features in 50% pts -CCBs with strong vasodilatory effect are C/I in pts with obstructive symptoms Disopyramide- has negative inotropic & vasoconstrictive effects -most effective agent to reduce LVOTO , gradient & relieving the symptoms
- 38. Indications Subaortic gradients≥ 50mmHg frequently assoc with CHF & are refractory to medication Septal Myotomy +Partial Mymectomy thru a transaortic approach relieves the obstruction, reduces the LVOTO gradient, SAM & MR Complications –CHB or septal perforation (0-2%) Mortality rate-1to 3% Intraop guidance & Evaluation of surgical result by an experienced echocardiographer are essential for the success of the procedure
- 39. Nishimura RA etal. NEJM. 2004. 350(13):1320.
- 40. Septal Ablation with Ethanol -Non surgical septal reduction therapy -2-5 ml of Ethanol is adm thru an angioplasty balloon catheter lumen to the first major septal perforator of the LAD - reduce LVOT grad in 85-90% pts immediately -Further ↓in grad & sympt improvement seen over next 3-6mths - Permanent heart blocks ( 5-10%) Dual Chamber or AV Sequential Pacing(DDD) -Exact mechanism unkn -Possible mech: Excitation of the septum of LV contracts it away from apposing wall which may reduce the LVOT gradient -now rarely recommended since symptoms actually worsen despite gradient reductions
- 41.
- 42. Before After
- 43. HCM is the most common cause of SCD in otherwise healthy young individuals VT /VF is primarily responsible for SCD Identification of High Risk Individuals is very important -Pts < 30yrs at the time of diagnosis -Prior cardiac arrest -Symptomatic VT on Holter monitor -Family H/O SCD or Syncope The only effective modality to prevent SCD in HCM pts is an ICD Pharmacological therapy for prevention of SCD in these pts has been abandoned
- 44. Aim of Anaesthetic management - Avoid aggravating the subaortic gradient Anaesthetic goals for a patient with HCM are same for cardiac or non cardiac surgery : Preload- Increased Afterload-Increased Contractility-Depressed Avoid tachycardia, Inotropes, Vasodilators To achieve these, -Maintain adequate volume status -Avoid direct or reflex increase in HR or contractility by heavy premedication & maintaining adequate anaesthesia & analgesia -Continuation of β blockers or CCBs upto the day of sx & restart immediately after sx -Use of vasoconstrictors to maintain MAP or CPP instead of Inotropes
- 45. Induction- IV Narcotics/ Propofol in carefully titrated doses can be used Maintenance-Halothane is advantageous because of its negative inotropic & chronotropic effect Intraop Hypotension- Trendelenburg position, Volume replacement, & Vasoconstrictors Arrythmia management -Asymptomatic Nonsustained VT-benign -Pts with ICD device needs to be suspended in presence of Electrocautery -Chronic AF :B Blocker+Verapamil -Amiodarone is effectve in restoring NSR in pts with HCM Monitoring ECG-closely monitor for arrythmias CVP/PAC/TEE- for volume status, Hemodynamic monitoring Avoid Inotropes, B agonists & Calcium
- 46. HCM Athletic heart Can be asymmetric Concentric & regresses with deconditioning Wall thickness: > 15 mm < 15 mm LA: > 40 mm < 40 mm LVEDD : < 45 mm > 45 mm Diastolic function: always Normal abnormal Occurs in about 2% of elite althetes – typical sports, rowing, cycling, canoeing 46 of 48
- 47. WHO in 1995 defined RCM as restrictive filling & reduced diastolic volume of either or both ventricles with normal or near normal systolic function & wall thickness Classification of RCM Myocardial Nonifiltrative – Idiopathic, Familial, HCM, Diabetic Infiltrative- Amyloidosis, Sarcoidosis Storage diseases- Haemochromatosis, Glycogen storage diseases Endomyocardial Endomyocardial fibrosis Carcinoid Radiation Drug Induced –Serotonin, Methysergide, Busulfan, Ergotamine
- 48. Hallmark –Abnormal Diastolic Dysfunction Impaired ventricular relaxation & abnormal Compliance causes rapid filling in early diastole & impeded filling during rest of diastole Characteristic -Ventricular diast waveform of Dip & Plateau (Square root sign) -RA pressure waveform-M or W shaped due to rapid y descent Pressure in the ventricle rises precipitously in response to small volume Both ventricles appear thick with small cavities in contrast to corresponding dilated atria Lt sided Pulmonary venous pressure >Rt sided venous pressure by 5mmHg PASP↑↑ upto 50mmHg Either RVF or LVF or BVF
- 51. Symptoms of Rt &/or Lt heart failure Kussmaul’s sign- ↑ JVP during inspiration Pulsus paradoxus- infrquent CXR- pulmonary congestion, small heart size ECG- BBBs, low voltage, QR or QS complexes 2D Echo
- 53. Characteristic RCM Constrictive Pericarditis Jugular venous ↑ with more rapid y descent ↑ with less rapid y descent waveform Paradoxical Pulse Rare Frequent Auscultation Late S3, low pitched, S4 occ Early S3,highpitched, No S4 Heart size N to ↑ N to ↑ MR/TR Frequently present Frequently absent CXR Pericardial calcification rare common ECG Conduction abn common rare ECHO Major enlargmt of Atria Slight enlargmt of Atria LAP>RAP Always Absent RVP waveform Square root pattern, Dip & Square root pattern Plateau less prominent RVEDP/LVEDP LVEDP>RVEDP by ↑ ↑ & Equal 5mmHg CT/MRI Rarely thickened Thickened pericardium>3mm pericardium Endomycardial Non specific abn Normal Biopsy
- 54. Idiopathic Diuretics-To relieve congestion B-blockers, Amiodarne, CCBs- Control of HR Long term anticoagulation CCBs, ACEI- To enhance myocardial relaxation Dual Chamber Pacing- AV block Cardiac Transplantation- Refractory Heart Failure Amyloidosis- Melphelan, prednisone, H+L transplant Haemochromatosis- Phlebotomy, Desferrioxamine Carcinoid- Somatostatin analogs, Valvuloplasty/Valve replacement Sarcoidosis –Steroids , Pacing, ICD, Transplantation EMF with eosinophilic cardiomyopathy: Endocardiectomy +TV/MV replacement
- 55. Adults with RCM present for CT or MVR/TVR Diastolic dysfunction + filling abn- Poor CO & systemic perfusion Aggresive preop diuretic tharapy- Severe hypovolemia Pulmonary Congestion leads to ↑ Airway pressures Induction-Avoid drugs causing ↓ venous return, bradycardia & myocardial depression Fentanyl (30u/kg), Sufentanyl, Etomidate , Ketamine provide stable hemodynamics for induction Remifentanil, Propofol –unsuitable Invasive hemodynamic monitoring & TEE Inotropic support to maintain CO Diuretics / Vasodilators may be deleterious because higher filling pressures are needed to maintain the CO
- 56. Progressive replacement of RV myocardium with fat & fibrous tissue creating an excellent envt of fatal arrythmias Typical involves regional RV→Global RV→Partial LV involvement with sparing of septum Familial Inheritance, adolescents Presentation -Onset of Arrythmias from RV range fromVPCs-VF -SCD 75% due to VT/VF in sports related exercise -CHF 25% -Progressive RV & LV Dysfunction Diagnosis- Genetics, ECG, Serial Echo, EM Biopsy ECG-Inverted T waves (Rt precordial leads) QRS >110ms Extrasystoles +LBBB
- 57. Any Family H/O SCD or syncope at an early age must alert the anaesthesiologist Arrythmias are more likely in the periop period Intraop /Postop Avoid any noxious stimuli Light anaesthesia Inadequate analgesia Hypercarbia Hypovolemia Acidosis-detrimental due to its effect on arrythmia generation & myocardial function GA perse doesn’t appear to be arrythmogenic Propofol , Midazolam, fentanyl-successfully used Amiodarone- Antiarrythmic of choice during Anaesthesia