A 64-year-old diabetic, hypertensive woman was found to be in persistent atrial fibrillation on routine examination. Despite an initial rate control strategy with combination carvedilol and diltiazem, she continued to have high ventricular rates ranging from 90 to 130 beats a minute.
A transthoracic echocardiogram revealed mild concentric left ventricular hypertrophy with an LV wall thickness of 1.1cm and an ejection fraction of 55%. Her estimated creatinine clearance was 72.5 mL/min (based on a creatinine of 1.2mg/dL and a weight of 97.2kg [213 lbs; BMI = 42]), potassium 3.7 mmol/L and magnesium 1.7 mmol/L. She was admitted for initiation of Sotalol and cardioversion. Carvedilol and diltiazem were discontinued. After 4 doses of sotalol at 80mg twice daily (under telemetric monitoring), she converted to sinus bradycardia at 46 bpm and a QTc of 420 ms (Figure 1). She was discharged home (on sotalol 80mg twice daily), with follow up scheduled in a week’s time. Six days later, the patient developed recurrent presyncope, ultimately culminating in an abrupt episode of syncope just after showering at a rehabilitation center.