Arrhythmias USMLE Step 1 Practice Question
A 24-year-old woman presents with sudden-onset palpitations and lightheadedness. Vital signs show BP 102/68 mmHg, HR 180 bpm, RR 18, temperature 37.2Ā°C, and SpO2 98% on room air. ECG reveals a regular narrow-complex tachycardia at 180 bpm with no clearly visible P waves. Troponin is normal. She denies chest pain or dyspnea. Carotid sinus massage terminates the rhythm. Which diagnosis best explains these findings?
Answer choices
- ACardiogenic shock
- BAV nodal reentrant tachycardiaCorrect answer
- CWolff Parkinson White syndrome
- DTorsades de pointes
- EAtrial flutter
- FSinus tachycardia secondary to anxiety disorder
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