American Board of Internal Medicine (ABIM) Certification Practice Exam

Which clinical sign is associated with atrial septal defect (ASD)?

1. Left ventricular hypertrophy

2. Right ventricular heave

3. ST elevation in leads I and II

4. Wide QRS complex

The correct answer is: Right ventricular heave

Atrial septal defect (ASD) is characterized by an opening in the atrial septum, allowing blood to flow from the left atrium to the right atrium. This left-to-right shunting leads to volume overload of the right atrium and pulmonary circulation over time. As a result, the most notable physical finding associated with ASD is a right ventricular heave. A right ventricular heave occurs due to the increased workload and enlargement of the right ventricle as it compensates for the heightened blood flow resulting from the shunting. As the right ventricle becomes more prominent, this heave can be palpated on examination of the chest wall, particularly along the left sternal border. In contrast, left ventricular hypertrophy occurs from chronic pressure overload and is more indicative of conditions such as aortic stenosis or systemic hypertension. ST elevation in leads I and II typically reflects superior wall ischemia or injury but is not indicative of ASD. A wide QRS complex often signifies ventricular conduction abnormalities or hypertrophy but is not specifically linked to the pathophysiology of ASD. Understanding these associations is crucial for the clinical assessment and diagnosis of cardiac conditions.