A New Tachyarrhythmia in a 60-Year-Old Woman.

A 60-year-old woman with a history of hypertrophic obstructive cardiomyopathy, paroxysmal atrial fibrillation, and metastatic rectal cancer presented to the emergency department with new-onset respiratory distress. The admission ECG is shown in Figure 1A. Given frequent rhythm changes noted on telemetry after intravenous diuresis and continuation of her home medications, a repeat ECG was ordered (Figure 1B). The presenting ECG (Figure 1A) shows regularized atrial fibrillation with ventricular bigeminy, whereas the second ECG (Figure 1B) is consistent with bidirectional ventricular tachycardia (BVT). [Extracted from the article]