Congenital Heart DiseasesCaridovascular lab #3Congenital heart disease General considerations Abnormalities of the heart and/or great vessels that are present from birth. Incidence- Approximately 6-8 per 1,000 live births Genetic and/or environmental factors play a role, but only 10% of cases have associated identifiable contributing factors.Congenital heart disease Age of Presentation Variable depending on type The minority are incompatible with intrauterine survival May present soon after birth ( right to left shunts ) Later in life, even adulthood ( ASD )Three Functional Categories Left to right shunts (“late cyanosis”) Right to left shunts (cyanotic congenital heart disease) Obstructions to flow (obstructive congenital heart disease)Left to Right Shunts “Late Cyanosis” Initially Left sided pressure right sided pressure ASD, VSD, or patent ductus arteriosis (PDA) - these may later become right to left shuntsObstructions to Flow “Obstructive Congenital Heart Disease” Abnormal narrowing (stenosis) or complete occlusion (atresia) of chambers, valves or blood vessels e.g. coarctation of the aorta, aortic valvular stenosis, pulmonary stenosis May have combinations of obstructive lesions and shunts- e.g. tetralogy of Fallot has pulmonary stenosis associated with a shuntRight to Left Shunts “Cyanotic Congenital Heart Disease” Less common than L to R shunts (Late cyanosis) Right sided pressure left sided pressure Blood is shunted away from pulmonary circulationRight to Left Shunts the five Ts Tetralogy (8%) Transposition of great vessels(5%) Tricuspid atresia (2%) Total anomalous pulmonary venous connection (2%) Truncus arteriosis (1%)( relative %s of congenital Heart dz)Tetralogy of Fallot Most common cause of right to left shunts Cyanosis is present from birth or soon after in most cases Hypoxia is variable and directly depends on the amount of pulmonary obstruction Pulmonary obstruction relates directly to amt shunted away from the lungs Correctable with surgery Some anatomic variations are harder to correct than others Surgery is not emergent as long as child can handle level of hypoxia (pulmonary obstruction protects the lungs from high pressures so unlike a big VSD, these pts dont need to be correctly quickly to avert pulmonary hypertension)Tetralogy of Fallot Treatment Correctable with surgery Some anatomic variations are harder to correct than others Surgery is not emergent as long as child can handle level of hypoxia Pulmonary vessels protected from VSD by pulmonic stenosis- alleviates need for immediate surgical interventionTetralogy of Fallot Four Anatomic Alterations “PROVe” Pulmonary stenosis Right ventricular hypertrophy (RVH) Overiding aorta (overriding VSD) VSDEdwards, JE: Congenital Heart Disease. WB Saunders and Co. 1965Diagramatic representation of the anatomic abnormalities and typical shunt of Tetralogy of Fallot. Notice the RV hypertrophy, large VSD, over -riding aorta and the pulmonary stenosis. The shunt is a result of the large VSD (which serves to equalize pressures between the right and left ventricles) and the pulmonic stenosis which directs more blood to the systemic circulation.Tetralogy of Fallot Pulmonary Stenosis Obstruction of pulmonary outflow tract Variable anatomic reasons- most commonly narrowing of infundibulum (subpulmonary stenosis Pulmonary vavle or arteries may be narrowed This causes the right to left shunting VSD by itself will cause left to right shunts Pulmonary obstruction actually protects pulmonary vasculature from the great pressures of the left ventricleGross example of Tetrology of Fallot. The interior of the right ventricle is exposed showing a large VSD (D) and an aorta (A)straddling (ie over-riding) the VSD. A probe (arrow) is positioned inside of the stenotic subpulmonary infundibular channel.Edwards, JE: Congenital Heart Disease. WB Saunders and Co. 1965Tetralogy of Fallot Right Ventricular Hypertrophy Surprisingly the RVH rarely leads to right heart failure RV failure prevented by abililty to decompress into left ventricle.This is an example of tetralogy of Fallot opened sagittally. The aorta and its valve (AV) clearly straddle the VSD (D) such that the aorta appears to arise equally from each ventricle. The right ventricular (RV) is clearly hypertrophic as it is nearly as thick as left ventricle (LV).Edwards, JE: Congenital Heart Disease. WB Saunders and Co. 1965Tetralogy of Fallot Overriding Aorta Location of VSD puts aorta over both ventricles VSDs upper border is made by aortic valve- Aorta then overrides both chambers ( see next diagram)This is an example of tetralogy of Fallot opened sagittally. The aorta and its valve (AV) clearly straddle the VSD (D) such that the aorta appears to arise equally from each ventricle. The right ventricular (RV) is clearly hypertrophic as i