Rosh Internal Medicine Boost Practice Exam

What is the most likely cause of the patient's palpitations and shortness of breath?

1. Myocardial infarction

2. Narrow-complex supraventricular tachycardia

3. Hypotension

4. Asthma exacerbation

The correct answer is: Narrow-complex supraventricular tachycardia

Narrow-complex supraventricular tachycardia (SVT) is a condition characterized by an abnormally fast heart rate originating above the ventricles. This abnormal rhythm can lead to symptoms such as palpitations and shortness of breath. In patients with SVT, the rapid heart rate can reduce cardiac output and may precipitate feelings of anxiety and difficulty breathing, as the body struggles to meet its oxygen demands. The context in which these symptoms appear can also help differentiate SVT from other potential causes. For instance, myocardial infarction typically presents with additional symptoms such as chest pain and can be associated with ST-segment changes on an ECG. Hypotension might lead to feelings of dizziness or faintness but is not usually characterized by palpitations; rather, patients are more likely to feel weak or unstable. Asthma exacerbations typically cause wheezing, cough, and a feeling of tightness in the chest rather than isolated palpitations and shortness of breath, which are more consistent with an irregular or rapid heart rhythm. In this scenario, the presence of palpitations and shortness of breath without the hallmark signs of other conditions strongly points toward narrow-complex supraventricular tachycardia as the most likely