INTRODUCTION TO CONGENITAL HEART DISEASE. Dr.B.BALAGOBI
Epidemiology• Prevalence:0.5-0.8% of live births (8/1000).• Leading structural malformation in infants.• Etiology: – Unknown – multifactorial inheritance • Genetic(Chromosomal/Single gene) • Teratogen(Maternal diseaes/Drugs)• 10-15% have extracardiac anomalies(VACTERL)• Gender differences:ASD,VSD,PDA & Pulmonic stenosis more common in girls,left sided lesions in boys.
FETAL CIRCULATION-EMBRYOLOGY• From placenta via umbilical vein• Blood by pass liver via Ductus venosus to IVC• Mix with blood from lower limb• This blood enters RA,Pressure in RA>LA• Major part of this blood pass via Foramen ovalae to the LA• Mix with desaturated blood from lungs at LA then enters to LV to Aorta• Coronary & carotid are the first branches – Well oxygenated blood
FETAL CIRCULATION• Desaturated blood from SVC flow to RA to RV to pulmonary trunk.• Major part of its blood pass directly through Ductus arteriosus in to desending aorta.• Then blood goes to placenta via umbilical Artery.
CHANGES AT BIRTH• At birth first breathresistance to pulmonary blood flow decrease rise in LA pressure• Placenta removal reduce venous return to RA reduce RA pressure Foramen ovale closed• Closure of – Umbilical artery – Umbilical vein – Ductus venosus – Ductus arteriosus – Foramen ovale
CYANOTIC DISEASE• TOF(Tetralogy of fallot)• TGV(Transposition of great vessels)• Tricuspid atresia• Truncus arteriosus• Total anomalous of pulmonary venous drainage• Hypoplastic left heart syndrome• Pulmonary atresia• Ebstein anomaly
Congenial Heart Disease divisons• Congenital Heart Lesions that INCREASE Pulmonary Arterial Blood Flow Plethoric lung Recurrent Chest infection. – Atrial Septal Defect – Ventricular Septal Defect – Patent Ductus Arteriosis – Complete Atrioventricular Canal – Total Anomalous Pulmonary Venous Connection – Truncus Arteriosus – Transposition of the Great Arteries• Obstructive Congenital Heart Lesions – Pulmonary Stenosis – Aortic Stenosis – Coarctation of the Aorta• Congenital Heart Lesions that DECREASE Pulmonary Arterial Blood Flow – Tetralogy of Fallot – Tricuspid Atresia – Ebstein’s Anomaly
PATHOPHYSIOLOGY• VSD,PDA Left to right shunt(increased pulmonary blood flow-No cyanosis)Load on left ventricle LVHCardiomegaly(Precordial bulge) Secondary Pulmonary hypertension(Loud P2,Parasternal heave)RVH Reversal of shunt Cyanosis(Eisenmenger syndrome)• But ASD first cause RVHso parasternal heave does not indicates Pulmonary hypertension.
CVS Examination• Pulse,JVP,BP – Rate(upper limit 160- 100,rhythum, volume(small:AS,bounding:anaemia,AR,PDA)• Inspection:precordial bulge,Scar,visible pulsation• Palpation:Apex,thrill,heave• Auscultation – Heart sounds S1,S2,S3(Normal in young children) – Split of S2 – Murmur(Timing,duration,loudness,radiation• hepatomegaly
PRESENTATIONS OF CHD• Antenatal cardiac USS• Detection of murmur• Cyanosis• Respiratory distress• Heart failure• Shock
Heart murmurs• Ejection systolic murmur – Ventricular outflow narrowing(AS,PS),ASD – May be normal• Pan systolic murmur – VSD,MR,TR• Continuous murmur – PDA – Venous hum(due to turbulent flow in head & neck veins,disaapears in lying down)• Hall marks of innocent murmurs – Systolic murmur,localised to left sternal edge,no diastolic component,no radiation,no thrill,no added sound,No symptoms• There may absence of murmur in severe CHD like PDA,large VSD
Innocent/functional murmurs• soft• Systolic• No diastolic component• Confined to small area,left sternal edge• No parasternal thrill• No radiation• Normal heart sounds• No added sound• Asymptomatic patient
T/F Circulatory changes that occur at birth include? A. Rise in left atrial pressure B. Drop in the pulmonary vascular resistance C. Rise in the volume of blood returning to the right atrium D. Closure of the foramen ovale E. Closure of the ductus arteriosus
T/F In fetal circulation?A. Umbilical vein carries oxygenated bloodB. Blood flow from left to right through foramen ovaleC. Pulmonary arterial pressure is highD. Oxygen saturation in right atrium is more than left atriumE. Coronary arteries origin from the pulmonary artery
T/F Features of functional murmur?A. Usually systolicB. Associated with thrillC. Common at left parasternal edgeD. Incidence more common in 1 year than 10 yearE. Radiates to axilla
T/F Right ventricular hypertrophy?A. Is a feature of Transposition of great vesselsB. Is a feature of tetralogy of fallotC. Is a characteristic feature of tricuspid atresiaD. In ASD indicates pulmonary hypertensionE. Cause tall R wave in V1 ECG lead.