Congenital Heart Disease PDF

Congenital heart disease These are abnormalities of the heart or the great vessels that are present since birth. Most of these abnormalities arise from faulty embryogenesis (3 – 8 weeks). They may be incompatible with intrauterine survival or associated with live birth. They may present soon after b...

Congenital heart disease These are abnormalities of the heart or the great vessels that are present since birth. Most of these abnormalities arise from faulty embryogenesis (3 – 8 weeks). They may be incompatible with intrauterine survival or associated with live birth. They may present soon after birth or in adult life. Causes: Genetic factors: Note! The familial forms of congenital heart disease & association with certain chromosomal abnormalities: Trisomy 21 → associated with Down syndrome: which is the most common genetic cause of congenital heart disease → (atrial septal defect, ventricular septal defect, ostium primum). Turner syndrome → associated with preductal coarctation of the aorta & bicuspid aortic valve. Environmental factors: Example → congenital rubella Maternal factors. Shunt: It is an abnormal communication between heart chambers or vessels Types: Right to left shunt: Blue skin & mucus membranes (cyanosis). Common causes are: 1. 2. 3. 4. Tetralogy of Fallot Transposition of great arteries Persistent trunchus arteriosus Tricuspid atresia It is associated with: Paradoxical embolism resulting in brain infarction & abscesses. Clubbing of fingers & toes (hypertrophic osteoarthropathy). Polycythemia. Left to right shunt: Features: Increased pulmonary blood flow (volume &/or pressure). Pulmonary hypertension & right ventricular hypertrophy. Pulmonary arteries show medial hypertrophy & vasoconstriction which if prolonged stimulates intimal obstructive lesions. With the high pressure the shunt is reversed & cyanosis appears → (late cyanosis or Eisenmenger syndrome). Causes: Causes: 1. Atrial septal defect (ASD): 2. Ventricular septal defect (VSD): 3. Patent ductus arteriosis Atrial septal defect (ASD) It is an abnormal opening in the atrial septum, allowing communication between the left & right atria. The shunt occurs from left to right because the pulmonary resistance is less ˂ than the systemic resistance, & because the right ventricle is more distensible than the left. Most patients become symptomatic after the age of 30. Pulmonary hypertension occurs in less ˂ than 10% of patient. Ventricular septal defect (VSD): It is the most common anomaly. There is an incomplete closure of the inter-ventricular septum. In 30% of cases it isolated. The clinical presentation depends on the size of the defect. It may close spontaneously. 90% “of defects” are in the region of the membranous septum (membranous VSD). 10% occur below the pulmonary valve (infundibular VSD) or within the muscular septum. “Defects” can be single or multiple. Clinical presentation: Depends on the size & presence of other anomalies. 50% of small muscular VSDs close spontaneously. Large defects cause a left to right shunt. Signs/symptoms: There is right ventricular hypertrophy & pulmonary hypertension from birth. Later pulmonary vascular disease develops with reversal of shunt & cyanosis. Closure of large defects is recommended by age 1 year. Patent ductus arteriosus (left to right then right to left): It the persistence after birth of the communication between the pulmonary arterial system & aorta. There are no functional difficulties at birth. There is a continuous harsh murmur → (machinery-like). First there is left to right shunt but when obstructive pulmonary vascular disease develops, reversal of shunts occurs. Tetralogy of Fallot: 1.VSD. 2.Sub-pulmonary stenosis causing obstruction to the right ventricular outflow tract. 3.Aorta over-riding the VSD. 4.Right ventricular hypertrophy. Some patients survive into the adult life. Clinical presentation: The direction of the blood flow is determined by the severity of the subpulmonary obstruction. Accordingly it is classified to: Pink tetralogy: Here there is mild sub-pulmonary stenosis that behaves like an isolated VSD. There is left to right shunt & no cyanosis. Classic tetralogy: There is severe obstruction with it; the right ventricular outflow is severe. & a right to left shunt develops with cyanosis Transportation of great vessels: Here the aorta arises from the right ventricle & the pulmonary arteries arise from the left ventricle. This is incompatible with life unless there is a shunt to allow for adequate mixing: VSD → (35%) have stable shunt Patent foramen ovale or Patent ductus arteriosus → (65%) Transporation of great vessels is associated with (diabetes of mothers). Persistence trunchus arteriosus: It is failure of separation of the embryologic trunchus arteriosus into the pulmonary artery & the aorta. Thus there is a single great artery receiving blood from both ventricles, accompanied by an underling VSD. In this case early cyanosis develops. Coarctation of aorta: Means narrowing of the aorta. The incidence is twice in males as in females (except females with “Turner syndrome” which frequently have it). Forms of coarctation of aorta: Infantile form: In which there is hypoplasia of the aortic arch proximal to a patent ductus arteriosus. Adult form: In which there is rigid unfolding of the aorta opposite to a closed ductus If there is Coarctation without a Patent ductus arteriosus there will be: Hypertension in the upper extremities. & weak pulse & low blood pressure in the lower extremities. Claudication Tumors of the heart Myxoma It is the most common primary tumor of the heart in adults. 90% are located in the atria, in the region of the fossa ovalis. Their size ranges from 1 – 10 cm. They are either Sessile or pedunculated. These tumors are globular & hard or soft → translucent. They are papillary or villous → gelatinous. The pedunculated forms can cause obstruction. Clinical features: Ball-valve obstruction causing: Fever Malaise & systemic embolization 10% have a family history of (Carney syndrome). Its features are multiple cardiac & extra-cardiac myxoma causing: Skin pigmentation lesions & multiple endocrine over-activity Rhabdomyoma It is the most common primary tumor of infants & children. It is considered as a hamartoma & it is associated with sclerosis. It may be caused by a defect in apoptosis during development & remodeling. Histology shows spider cells containing myofibrils → these are large cells containing (glycogen vacuoles & there cytoplasm strands are running from the plasma membrane to the nucleus).