The LA pressure is low The RA pressure is higher than LA ( receives all sys VR) The flap valve of foramen ovale is held open Blood across the atrial septum to LA With the 1 st breath, resistance to pulm BF falls and volume of blood returning to RA falls Changes in pressure difference cause flap valve of FO to be closed.
The ductus arteriosus will normally close within first few hrs or days Some babies with CH lesion rely on BF through the duct. Clinical condition deteriorate dramatically when duct closed (1-2 days)
Congenital heart disease Definition: Failure of normal cardiac development or persistent of the fetal circulation after birth.
Epidemiology CHD occurs in 8 per 1000 infants . About 1 in 10 stillborn infants have a cardiac anomaly. About 10-15% have complex lesions with more than 1 cardiac abnormality. About 10-15 % also have non-cardiac abnormality. CHD is the most common group of structural malformations in children.
Classification CHD Acyanotic Cyanotic - Ventricular Septal Defect (VSD) - Persistent Ductus Arteriosus (PDA) - Atrial Septal Defect (ASD - Pulmonary Stenosis - Aortic Stenosis -Coarctation of aorta Teralogy of Fallot transposition of the great arteries Atrioventricular septal defect Left-to-right shunts Outflow obstruction
Ventricular Septal Defects (VSD) Common – 25-30% of all cases of CHD. There is a defect anywhere in the ventricular septum , usually perimembranous (adjacent to the tricuspid valve) or muscular (completely surrounded by muscle). Location of the VSD – prognostic and repair approach. The amount of flow crossing a VSD depends on the size of defect and the pulmonary vascular resistance.
At birth, the pulmonary vascular resistance is normally elevated , thus, even large VSDs are not symptomatic at birth. Over the first 6-8 weeks of life, pulmonary vascular resistance normally decreases . More blood flows through the lung and into the left atrium. However, in VSD, the amount of shunt increases , and symptoms may start to develop. The size of the VSD affects the clinical presentation.
Pathophysiology VSD permits a left-to-right shunt to occur at the ventricular level with 3 adverse hemodynamic consequences: left ventricular (LV) volume overload, increased pulmonary blood flow, compromise of systemic cardiac output. In time, as PVR increases, irreversible histologic changes may occur within the pulmonary vascular bed. Untreated, a reversal of the flow occurs, leading to a right-to-left shunt with the development of increasing cyanosis (Eisenmenger complex).
Small VSDs Smaller than the aortic valve in diameter (3mm). Clinical features Symptoms Asymptomatic Physical signs Thrills at lower sternal edge Loud pansystolic murmur at lower left sternal edge Quiet pulmonary second sound (P2)
Investigations Chest X-ray - normal ECG - normal Echocardiography Demonstrates the precise anatomy of the defect. Assessment of haemodynamic effect using Doppler echocardiography.
Management Most will close spontaneously . Ensure by the disappearance of the murmur, normal ECG on follow up, normal echocardiogram. While the VSD is present, for prevention of bacterial endocarditis : Maintain good dental hygiene Antibiotic prophylaxis before dental extraction or any operation where there’ll be bleeding Surgical closure may not be required
Large VSDs Defects are the same size or bigger than the aortic valve. Clinical features Symptoms Heart failure with breathlessness and failure to thrive after 1 week old Recurrent chest infections Physical signs Prominence of the left precordium Soft pansystolic murmur Apical mid-diastolic murmur at the apex Loud pulmonary second sound (P2) Tachypnoea, tachycardia and enlarged liver from heart failure.
Investigations Chest X-ray Cardiomegaly Enlarged pulmonary arteries Pulmonary vascular markings Pulmonary oedema ECG Biventricular hypertrophy by 2 months of age and signs of pulmonary HPT right ventricular enlargement and hypertrophy Echocardiography Demonstrates the anatomy defect, haemodynamic effects and severity of pulmonary HPT.
X-Ray chest PA View There is cardiomegaly, prominent main pulmonary artery segment and right pulmonary artery. Enlarged left pulmonary artery shadow is seen below the left cardiac border, within the cardiac silhouette. The enhanced vascular markings are visible on the right side whereas it is obscured by the cardiac shadow on the left side cardiomegaly Increased pulm markings Enlarged pulm arteries
Management Initial treatment – diuretics and digoxin/captopril. Continued poor growth or pulmonary HPT requires closure of the defect . Most VSDs are by surgery . But muscular defects by devices placed at cardiac catheterization. Surgery is usually done at 3-6 months of age for : Managing heart failure and failure to thrive. Prevent permanent lung damage from pulmonary HPT and high blood flow.
Atrial Septal Defects (ASD) Due to failure of septal growth or excessive reabsorption of tissue. Represent about 10% of CHD. Classification: Secundum ASD (80%) Defects occur from either excessive resorption of septum primum or from deficient growth of septum secundum. Primum ASD or partial atrioventricular septal defect I ncomplete fusion of septum primum with the endocardial cushion. An inter-atrial communication b’ween the bottom end of the atrial septum and the atrioventricular(AV) valves. Abnormal AV valves, with a left AV valve having 3 leaflets and tends to leak (regurgitant valve).
Pathophysiology Shunting across an atrial septal defect is left to right The degree of this shunting is dependent on; - the size of the defect - the relative compliance of the right and left ventricles. - the relative vascular resistance in the pulmonary and systemic circulations. Resistance in the pulmonary vascular bed is commonly normal in children with ASD, and increase in volume load is usually well tolerated However, altered ventricular compliance with age can result in an increased left-to-right shunt contributing to symptoms. The chronic significant left-to-right shunt can alter the pulmonary vascular resistance leading to pulmonary arterial hypertension, even reversal of shunt and Eisenmenger syndrome.
Echocardiography: RV dilation with RV pressure overload as evidenced by flattening of the interventricular septum in systole.
Prognosis & Complications ASDs detected in term infants may close spontaneously. Secundum ASDs are well tolerated during childhood, and symptoms do not usually appear until the 3rd decade or later. Complications: Congestive heart failure Arrhythmias Pulmonary hypertension Cyanosis Stroke Infective endocarditis Surgery may be associated with a long-term risk of atrial fibrillation or flutter. The risk of infective endocarditis exists during the first 6 months after surgery.
Patent Ductus Arteriosus (PDA) The ductus arteriosus allows blood to flow from the pulmonary artery to the aorta during fetal life. This changes to the opposite after birth. In term infants , it normally closes shortly after birth. Failure of the normal closure of it by a month post term is due to a defect in the constrictor mechanism of the duct. In preterm infants , the PDA is not from CHD but due to prematurity .
Pathophysiology Higher aortic pressure, blood shunts left to right through the ductus The magnitude of the excess pulmonary blood flow depends on: The larger the internal diameter of the narrowest portion of the ductus arteriosus, the larger the left-to-right shunt. If the ductus arteriosus is restrictive, then the length of the narrowed area also affects the magnitude of the shunt. A longer ductus is associated with a smaller shunt. Relationship of the pulmonary vascular resistance to the systemic vascular resistance. If the systemic vascular resistance is high and/or the pulmonary vascular resistance is low, the flow through the ductus arteriosus is potentially large. If the PDA is large, pulmonary artery pressure may be elevated to systemic levels during both systole and diastole. Extremely high risk for the development of pulmonary vascular disease if left unoperated.
d) PDA visualised on angiography. e) A coil used to close the ducts. It’s passed through a catheter via the femoral artery. f) angiogram to show coil in the duct
Complication Complications include the following: Endocarditis Congestive heart failure Pulmonary vascular obstructive disease Aortic rupture
Outflow Obstruction Pulmonary stenosis – 7 % Aortic stenosis – 5 % Coarctation of the aorta – 5%
Pulmonary stenosis Narrowing of the pulmonary valve opening that increases resistance to blood flow from the right ventricle to the pulmonary arteries.
Site: Valvar (most), supravalvar, or subvalvar The valve may have only two or one leaflets The leaflets that are partially fused together Three leaflets, but thick and partly or completely stuck together narrowing of the valve
Pathophysiology The right ventricle pump harder and at a higher pressure to propel blood through the valve Right ventricular hypertrophy Pulmonary valve is mildly to moderately narrowed
severe stenosis in a neonate Right ventricle cannot eject sufficient volume of blood flow into the pulmonary artery Right ventricular pressure becomes extremely high Right-to-left shunt cyanosis Lead to right-to-left shunting through a patent foramen ovale/ atrial septal defect
Clinical features Severity depend on degree of stenosis Most asymptomatic (mild) Moderate – Severe : Exertional dyspnoea, easily fatigability, rapid breathing, shortness of breath, chest pain (angina), cyanosis may develop as the child gets older.
Physical sign: heart murmur Sys ejection murmur best heard at 2 nd IS (P 2 ) which radiates to the back Thrill may present In severe: impulse at the left sternal border(RVH) Often associated with click sound
Investigation Normal or post-stenotic dilation of the pulmonary artery Shows evidence of right ventricular hypertrophy Chest X-ray ECG
Management Mild: (peak sys gradient < 50 mmHg) Treatment not indicated SBE prophylaxis Moderate-severe (>50 mmHg) Transcatheter ballon valvuloplasty Neonatal critical PS Charc: cynosis and Rvdysfn Temporary stabilization with IV prostaglandin E infusion Early transcatheter ballon valvuloplasty
Aortic stenosis a narrowing of the valve that opens to allow blood to flow from the left ventricle into the aorta and then to the body.
Valvular, subvalvular or supravulvalar – 5% Failure of : development of the three leaflets Resorption of tissue around the valve
Pathophysiology narrowed aortic valve the LV must pump under very high pressures Left ventricular hyperthropy Mild stenosis: usually well tolerated, with minimal hypertrophy and normal LV function. Severe hypertrophy and valvar obstruction: myocardial ischemia dt limited CO, reduced coronary perfusion, and increased myocardial oxygen consumption. Fibrosis may occur in areas of the myocardium damaged by ischemia.
Clinical manifestation Depend on degree of stenosis Mild to moderate : asymptomatic Severe: easy fatigability, exertional chest pain, syncope In infant with severe stenosis can survive only if: PDA permits flow to the aorta and coronary arteries
Physical sign: Small volume, slow rising pulse Sys ejection murmur at R2ndIS and radiating to neck Apical ejection click Thrill at RUS border/suprasternal notch/carotid Cong bicuspid aortic valve: Prone to calcific degeneration in middle age Increased risk of infective endocarditis Single cusp AV : commonly aw early sudden death
Investigation ECG and CXR Mild: both normal Moderate – severe: CXR: LVH, poststenotic dilation of ascending or aortic knob ECG : site, valve morphology, LVH and estimated pressure gradient
Treatment Ballon valvulopasty Symptoms on exercise/ high resting pressure gradient(>64mmHg) High risk of significant valvular insufficiency Surgical mx When BV unsuccesful or significant valvular insufficiency develops Subacute bacterial endocarditis prophylaxis
Coarctation of aorta a narrowing of the aorta, usually just before the point where the ductus arteriosus joins the aorta.
Its almost always juxtaductal in position (98%) 2X more common in males 25% of patients with Turner’s Syndrome have coarctation of aorta Associated Defects: Bicuspid aortic valve (most common associated defect seen in 50%) VSD ASD
Pathophysiology afterload on the left ventricle (LV), which results in increased wall stress LV hypertrophy LV afterload may gradually increase, allowing children with less severe coarctation to develop arterial collateral vessels that partially bypass the aortic obstruction. These children may be asymptomatic until hypertension is detected or another complication develops. Acute increased in afterload lead to rapid development of CHF and shock.
The aorta narrows reduces blood flow to the lower half of the body the BP is lower than normal in the legs and tends to be higher than normal in the arms HPT
Clinical manifestation Depends on the severity of COA Asymptomatic In older children: Leg discomfort with exercise Headache Epistaxis Infant severe COA: Dependent on a PD to provide flow to des aorta Closed: resp distress, shock
Physical sign: Systemic HPT in the arm Diminished lower extremities pulses Radio-femoral delay: blood bypassing the obst via collateral vessels in the chest wall Ejection sys murmur at US edge
Investigation CXR : rib notching with large collaterals ECG: LVH
(a) Coarctation of the aorta. There is narrowing of the aorta distal to the left subclavian artery adjacent to the insertion of the arterial duct. (b) Murmur. (c) Chest X-ray. (d) ECG.
CHEST XRAY red : rib notching caused by the dilated intercostal arteries. yellow : the aortic knob blue : the actual coarctation green : the post-stenotic dilation of the descending aorta. Coarctation of the Aorta
Management Neonatal severe COA: Sick infant require temporary stabilization Mechanical ventilation Correction of met acidosis, hypoglycaemia and EI IV PE infusion Early surgical repair Asymptomatic/ older children: Depends on morphology of coarctation and age of presentation Primary transcatheter ballon angioplasty Stent implantation Surgical repair
Summary Lesion Signs Management Aortic stenosis Murmur: upper Rsternal edge carotid thrill Ballon dilatation Pulmonary stenosis Murmur: upper L sternal edge no carotid thrill Ballon dilatation Coarctatio of aorta systemic HPT Radio-femoral delay Stent insertion or surgery
Definition: Cyanosis: A bluish discoloration of skin and mucous membrane due to excessive concentration of reduced hemoglobin (deoxygenated) in the blood (Dorland’s Pocket Medical Dictionary, 27 th ed.)
Central vs peripheral Central cyanosis: Seen on tongue as a slate blue colour Associated with a fall in arterial blood O 2 tension. Clinically: reduced(deoxygenated) Hb >5g/dL SpO 2 = <85% Anemia? Polycythemia? Peripheral cyanosis: Blueness of hand and feet Due to cold or circulatory disorder (e.g: PVD, DVT) Can also occur in severe central cyanosis (Illustrated Textbook of Paediatrics, 3 rd ed., p.287)
Causes of cyanosis in CHD: RIGHT to LEFT shunt Systemic venous return Right heart Left heart Systemic circulation
5”Ts” Tetralogy of Fallot Transposition of the great arteries Tricuspid atresia Truncus arteriosus Total anomalous pulmonary venous return
Introduction: Most common cyanotic CHD, ~10% of all CHD 4 structural defects Pulmonary stenosis (most commonly subvalvular or infundibular) Overriding of the aorta Ventricular septal defect,VSD (L). Right ventricular hypertrophy, RVH Due to abnormalities in the septation of the truncus arteriosus into the aorta and pulmonary arteries that occur early in gestation (3-4weeks) (Nelson p674)
Clinical manifestations: Most are dx: Antenatally 1 st and 2 nd month of age: Pulmonary stenosis causing ejection systolic murmur. Cyanosis: the degree depends on the amount of PS Older children+ long standing cyanosis+ not undergone surgery Dusky blue skin Grey sclerae with engorged blood vessel Marked clubbing of fingers and toes
Hypoxic spells/ paroxysmal hypercyanotic attacks (1 st 2years of life) Severe hypoxia tissue acidosis breathlessness and pallor Rapid increase in cyanosis Restless and agitated Inconsolable crying An ambulatory toddler may squat Severe spells: Prolonged unconsciousness and convulsions Hemiparesis OR death
Investigations: Chest X-ray Small heart Uptilted apex (boot shaped) pulmonary artery ‘bay’= concavity of L heart border Oligaemic lung fields ECG At birth normal Older: R axis deviation and RVH Echocardiography Levels of PS and degree of stenosis Coronary anomalies(5% in TOF) (Nelson p675)
Management: Hypercyanotic spells (beyond about 15 minutes): O 2 administration Placing the child knee-chest position (inc VR) Give morphine sulfate (to relax pulmonary infundibulum and for sedation) Phenylephrine(an α - adrenoreceptor agonist ) β -adrenergic antagonists (propranolol)
Management: Single stage primary surgical repair between 1-2years old Indications for palliative modified Blalock Taussig shunt: Hypercyanotic spells/ severe cyanosis <6months Small pulmonary arteries Anomalous coronary artery crossing in front of RV outflow tract Life-long follow up (Handbook of Hospital Paediatrics, 2 nd ed., p94 )
Introduction: 5% of CHD (the most common cyanotic CHD in newborn period) Ventriculoarterial discordance 2 0 to abnormalities in septation of truncus arteriosus Aorta arises from the RV, anterior and to the right of the pulmonary artery, which arises from the left ventricle Naturally occurring associated anomalies that cause mixing: VSD ASD PDA
Clinical manifestations Cyanosis is always present Finger clubbing Quiet tachypnea Single S2 Usually no murmur Signs of CHF in children with transposition and a large VSD.
Investigations: Chest x-ray Narrow upper mediastinum with an ‘egg on side’ appearance of the cardiac shadow Increased pulmonary vascular markings ECG Right axis deviation and RVH Echocardiography Transposition of the great arteries The sites Amount of mixing
Management: Simple (TGA) with intact ventricular septum: IV Prostaglandin E 1 infusion Early Balloon arterial septostomy (BAS) Surgery: arterial switch procedure (2-4weeks of age) TGA with VSD: No treatment during neonatal period, but may develop heart failure 1-2months age Elective one-stage arterial switch operation + VSD closure before three months of age. TGA with VSD and PS: Blalock Taussig shunt during infancy followed by Rastelli repair at 4-6years of age.
Introduction: Approximately 2% of all CHD Normal development of the valve from endocardial cushions and septal tissue fails RV is small and nonfunctional (hypoplastic) All systemic venous return must cross the atrial septum into the left atrium. PDA,ASD and VSD are necessary
Clinical manifestations: Severely cyanosis Single S 2 If VSD present, pansystolic murmur may be audible.
Investigations: Chest x-ray: Normal or mildly enlarged Oligaemic lung fields ECG: LVH Superior QRS axis Echocardiograph Lesions Source of pulmonary blood flow
Management: Small or no VSD: PG E 1 Surgery: Blalock Taussig procedure Bidirectional Glenn and Fontan procedure Complete corrective surgery: not possible
Introduction: <1% of all cases of CHD Failure of septation of the truncus arteriosus (3-4weeks of gestation) Large single arterial trunk and VSD immediately below the valve
Clinical manifestations: Degrees of cyanosis depends on amount of pulmonary blood flow Infant may develop signs of CHF Signs: Tachypnea and cough Peripheral pulses are bounding Single S 2 Systolic murmur at left sternal border
Investigations: Chest x-ray: Increase pulmonary blood flow Displaced pulmonary arteries ECG: Combined ventricular hypertrophy Cardiomegaly Echocardiography: VSD Truncal valve function Origin of the pulmonary arteries
Management: Medications: anticongestive medications Surgery: VSD closure Placement of conduit between the right ventricle and pulmonary arteries before 3months of age.
Introduction 1% of CHD Disruption of normal development of normal pulmonary venous drainage during the 3 rd week of gestation results in 1 of 4 abnormalities 4major anatomic types: Supracardiac Cardiac Infracardiac Mixed
Clinical manifestations: Depends on the presence or absence of obstruction to the pulmonary venous drainage Infants with obstruction: cyanosis, marked tachypnea, dyspnea and signs of RHF Continuous murmur Hyperactive right ventricular impulse Widely split S 2 Ejection systolic murmur at the left upper sternal border
Investigations: Chest x-ray: normal or mildly cardiomegaly Varying degrees of pulmonary edema ECG: With obstruction: RV volume overload Right axis deviation RVH Echocardiograhy: Right heart volume overloaded R-L atrial level shunting PV (site of drainage and degree of obstruction)
SUMMARY LESION CLINICAL FEATURES MANAGEMENT TOF Loud murmur at the upper left sternal edge, with a single second heart sound Clubbing of fingers and toes (older) Hypercyanotic spells (rare) Surgery at 1-2years Tranposition of the great arteries Cyanosis is typical Single S2 Usually no murmur. Prostaglandin infusion, some need balloon atrial septostomy at diagnosis Arterial switch operation in neonatal period Tricuspid atresia Severely cyanotic Single S2 Pansystolic murmur PG E1 Shunt (Blalock-Taussig) or pulmonary artery banding Surgery ( Bidirectional Glenn and Fontan procedure) Truncus arteriosus Tachypnea and cough Peripheral pulses are bounding Systolic murmur at left sternal border Single S2 anticongestive medications Surgery: VSD closure Placement of conduit between the right ventricle and pulmonary arteries. Total anomalous pulmonary venous pressure Continuous murmur Hyperactive right ventricular impulse Widely split S 2 Ejection systolic murmur at the left upper sternal border Open and ligation
CASE STUDY A 5-hour old newborn on the postnatal ward is noticed by the midwife because he looks blue around the lips and tongue. He is the first child of a 7y/o mother with asthma who was taking inhaled steroids throughout pregnancy. Antenatal scans were unremarkable. She went into spontaneous labour 41weeks and there was thin meconium staining of the liquor when the membrane ruptured 1hour before delivery. CTG monitoring during labour revealed normal variability of fetal heart rate. The baby was born by oral vaginal delivery and weighed 3.3kg. The Apgar scores were 7 at 1 min and 8 at 5 min. Examination: the baby is dysmorphic. His temperature is 36.6 0 C and his central capillary refilling time is 2s. His lip, tongue and extremities are cyanosed. He is crying normally and no signs of increased respiratory effort. Heart rate is 160 bpm., femoral pulses are palpable, heart sounds are normal and no murmur audible. Oxygen saturation is 70% in air and does not rise with facial oxygen, which has been administered by midwife. There is no hepatosplenomegaly.
Murmurs Normal* Defect Characteristic ASD Ejection (mid) Systolic murmur(3 rd L i/c space) Rumbling mid diastolic murmur (lower L sternal edge) in larger shunt Grade I or II VSD Physiologic splitting of S 2 is usually retained. The characteristic harsh, holosystolic murmur is loudest along the lower left sternal border (LSB), and it is well localized. Small defects can produce a high-pitched or squeaky noise. The holosystolic murmur; less harsh, more blowing in nature and even is less likely to be audible in the newborn period. Pulmonic component of the 2nd heart sound may be increased as a result of pulmonary hypertension. PDA Continuous At left infraclavicular area Radiates along pulm arteries, well heard at the back Larger shunt; Mid diastolic murmur Aortic Stenosis Systolic R 2 nd intercostal space, along sternum Radiate to neck Coarctation of aorta Ejection systolic Left intrascapular area of the back Continuous murmur through out chest if significant collateral developed