by Kelvin N.V. Bush, MD, and Gregg G. Gerasimon MD
A 70-year-old man with ischemic heart disease, chronic heart failure, and a left ventricular ejection fraction of 0.25 presented with recurrent palpitations and diaphoresis. His single-chamber implantable cardioverter-defibrillator had recently been upgraded to a Dynagen™ X4 Cardiac Resynchronization Therapy Defibrillator (Boston Scientific Corporation), and he had been taking β-blockers and amiodarone. Physical examination results were notable for hemodynamic stability, jugular venous distention, a jugular venous pressure of 12 cm H2O, and no evidence of pulmonary or hepatic congestion. The patient’s resting electrocardiogram (ECG) revealed a wide-complex rhythm (Fig. 1).
