Rosh Pediatrics Practice Exam

What ECG finding is likely to be observed in a 15-year-old boy with hypertrophic obstructive cardiomyopathy?

1. Downsloping ST elevation in leads V1-V3

2. Prominent Q waves in leads V1 and V2

3. T wave inversion in V1 and V2

4. Widespread ST elevation

The correct answer is: Prominent Q waves in leads V1 and V2

In a 15-year-old boy with hypertrophic obstructive cardiomyopathy, prominent Q waves in leads V1 and V2 reflect the abnormal electrical activity associated with this condition. Hypertrophic obstructive cardiomyopathy is characterized by asymmetric septal hypertrophy and can lead to obstruction of the left ventricular outflow tract. As a result of the hypertrophy and altered conduction pathways, the ECG may exhibit prominent Q waves. These Q waves can be indicative of a prior myocardial infarction or can represent a normal variant in certain conditions, including hypertrophic cardiomyopathy. In this case, the prominent Q waves suggest that there is significant left ventricular hypertrophy affecting the septal wall, leading to an alteration in the vector of ventricular depolarization. Other options do not align with the typical ECG findings commonly associated with hypertrophic obstructive cardiomyopathy. For instance, downsloping ST elevation in leads V1-V3 might suggest other forms of cardiac stress or cardiomyopathy, while T wave inversion in those leads is more characteristic of myocardial ischemia, and widespread ST elevation does not correlate with hypertrophic obstructive cardiomyopathy but rather points toward pericarditis or early repolarization phenomena. Understanding the specific ECG changes can aid