Congenital Heart Defects Flashcards
What is a congenital heart defect?
any abnormality of the heart or vessel that is present at birth.
What are the causes of congenital heart defects?
- genetic mutations (ex. trisomy 21).
- environmental factors (teratogens, rubella, gestational diabetes).
What is a MILD congenital heart defect?
affects a discrete chamber or region, but is compatible with embryologic maturation.
What is a MODERATE congenital heart defect?
produces clinically significant manifestations that appear shortly after birth with transitioning circulation.
What is a SEVER congenital heart defect?
incompatible with intrauterine survival
What is the incidence of congenital heart defects in the USA?
1% or 40,000 each year
**What are the 12 most common congenital heart defects?
she said we must memorize
- VSD
- ASD
- pulmonary stenosis
- PDA
- Tetralogy of Fallot
- Coarctation of the aorta
- Atrioventricular septal defect (AVSD)
- aortic stenosis
- transposition of the great arteries
- persistent truncus arteriosus
- total anomalous pulmonary venous connection
- tricuspid atresia
What are the 3 primary categories of congenital heart defects?
- left-to-right shunts
- right-to-left shunts
- obstruction
What is a left-to-right shunt?
abnormal channel that permits blood flow down a pressure gradient from the left (systemic) side to right (pulmonary) side.
What are the clinical characteristics of a left-to-right shunt?
- no initial cyanosis
- increased pulmonary blood flow and pressure that can lead to RV hypertrophy and atherosclerosis of pulmonary vasculature.
- medial hypertrophy and vasoconstriction of pulmonary arteries leading to vascular cell proliferation and obstructive intimal lesions.
What happens when pulmonary vascular resistance approaches systemic levels with a left-to-right shunt?
a right-to-left shunt will occur (late cyanosis)
What are the 4 defects that are left-to-right shunts?
remember the 4 D’s
- ASD
- VSD
- PDA
- AVSD
What is an atrial septal defect (ASD)?
an abnormal, fixed opening in the atrial septum that permits shunting of blood between the left and right atria.
What are the major ASD subtypes?
secundum (90%), primum, and sinus venosus
What are the clinical features of ASD?
- right sided overload (due to left-to-right shunt).
- increased pulmonary blood flow and pulmonic valve murmur.
- asymptomatic before age 30.
- low mortality
- can be corrected surgically.
What is a VSD?
incomplete closure of the ventricular septum that permits blood flow between the left and right ventricles.
*MOST common form of congenital heart defect and usually associated with other congenital heart defects.
What are the major VSD subtypes?
membranous (90%), and muscular
What are the clinical features of VSD?
- RV hypertrophy and pulmonary hypertension (due to left-to-right shunt).
- 50% close spontaneously.
- long-term effects= pulmonary vascular disease, shunt reversal, cyanosis and death.
- treat surgically.
What is a patent ductus arteriosus (PDA)?
incomplete closure of the ductus arteriosus after birth, permits blood flow between pulmonary artery to aorta.
- 90% are isolated, 10% are associated with other defect.
How can we maintain the PDA if it is needed in certain situations (other congenital defects like aortic valve atresia) that require the shunting of oxygenated blood?
using prostaglandins
What can cause a PDA during pregnancy?
pregnancies complicated by hypoxia and rubella
What are the clinical features of a PDA?
- initial left-to-right shunt with no cyanosis.
- harsh “machinery-like” murmur.
- asymptomatic at birth.
- volume and pressure overload produces obstructive changes in pulmonary arteries to reverse shunt after birth.
What is an atrioventricular septal defect (AVSD)?
failure of superior and inferior endocardial cushions to adequately fuse in AV canal, resulting in incomplete closure of the AV septum and malformation of AV valves.
What are the major subtypes of AVSD?
- partial AVSD= primum ASD + cleft anterior mitral valve leaflet.
- complete AVSD= common AV valve leads to volume overload hypertrophy.