Types of Congenital Heart Disease on the Physician Assistant Exam
Many types of congenital heart disease exist. There are certain conditions you’re likely to see on the Physician Assistant Exam (PANCE). Many of the congenital heart diseases you read about here are detected at birth and have telltale signs and features that you need to know.
Atrial septal defect
In atrial septal defect (ASD), someone has a defect or opening in the atrial septum between the right and left atria. Over time, this causes blood from the left atrium to enter the right atrium. Atrial septal defect increases the volume of fluid and blood over what the right-sided circulation would normally handle. Initially, the left-sided pressures are higher than the right-sided pressures.
If the flow of blood from the left atrium to the right atrium continues, a kind of reversal happens. Increased pressure develops on the right side. The patient then develops a right-to-left shunt, which is called Eisenmenger’s syndrome. You can see this shunt in any type of cyanotic congenital heart disease, but it’s most likely to come up in reference to atrial septal defect.
Here are some key points about atrial septal defect:
You can hear a midsystolic murmur with an increased P2 component of the S2.
The most common type of atrial septal defect is ostium secundum.
There’s a fixed splitting of the S2, which is a common giveaway on medical exams.
A good imaging procedure to see whether a shunt is present is a specific kind of echocardiographic study called a bubble study (a transcranial Doppler with bubble contrast).
The treatment is surgical intervention. The outcome is better if persistent pulmonary hypertension hasn’t yet developed.
Persistent patent ductus arteriosus
The patent ductus arteriosus (PDA) is a link between the pulmonary artery and the arch of the aorta that’s supposed to close during the first month after birth. In a patient with patent ductus arteriosus, this connection stays intact, which is not a good thing. Blood from the aorta flows backward into the pulmonary circulation and the lungs, which can cause problems, including pulmonary edema and congestive heart failure.
With untreated patent ductus arteriosus (just as with an untreated atrial septal defect), the affected person can develop Eisenmenger’s syndrome (a right-to-left shunt). The treatment is usually surgical.
Note that NSAIDs can be used to help close the patent ductus arteriosus, because prostaglandins can help keep this shunt open. That being said, surgical intervention can be curative.
Ventricular septal defect
Ventricular septal defect is a congenital tear in the ventricular septum. It causes a left-to-right shunt. Unlike atrial septal defect and patent ductus arteriosus, the ventricular septal defect isn’t a form a cyanotic congenital heart disease. Here are a few key points concerning ventricular septal defect:
It’s the most common cause of congenital heart disease in newborns.
It doesn’t cause Eisenmenger’s syndrome (a right-to-left shunt).
It’s one of the big four heart defects in tetralogy of Fallot.
On physical examination, you hear a holosystolic murmur. For PANCE purposes, recall that the two other causes of holosystolic murmurs are mitral regurgitation and tricuspid regurgitation.
Although ventricular septal defect can sometimes be treated by just following it closely, it usually requires surgical intervention.
The telling tetralogy of Fallot
Tetralogy of Fallot (TOF) is a congenital heart defect, the most common cyanotic heart defect, and the most common cause of blue baby syndrome. In terms of PANCE questions, you just need to know the parts of the syndrome. Here are four aspects of tetralogy of Fallot:
Ventricular septal defect (VSD)
Right ventricular hypertrophy
Because tetralogy of Fallot is a form of cyanotic congenital heart disease, manifestations include cyanosis. The cyanosis is a cause of the secondary polycythemia that you see in cyanotic congenital heart disease. The treatment for this condition is primarily surgical.