Pilsicainide Intoxication Presenting With Alternating Accelerated Idioventricular and Junctional Escape Rhythms...

Pilsicainide is a class Ic sodium channel blocker that is eliminated predominantly by the kidneys and may accumulate when renal function deteriorates. An 85-year-old man receiving pilsicainide 150 mg/day developed acute kidney injury (AKI) during hospitalization for hemorrhagic colitis. He subsequently developed impaired consciousness, dyspnea, pulmonary congestion, and alternating episodes of junctional escape rhythm at 30-37 beats/min and a regular, wide QRS rhythm at 79 beats/min. The QRS duration was approximately 150 ms, and the serum pilsicainide concentration was 3.19 µg/mL. The wide QRS rhythm was considered most consistent with pilsicainide-associated accelerated idioventricular rhythm accompanied by marked intraventricular conduction delay. Pilsicainide and bisoprolol were discontinued, and continuous hemodiafiltration was initiated because of severe toxicity accompanied by AKI, hyperkalemia, and volume overload. The patient's level of consciousness, hemodynamic status, and electrocardiographic abnormalities improved; the QRS duration narrowed to 104 ms, and the serum pilsicainide concentration decreased to 0.8 µg/mL. This case emphasizes that a relatively slow, regular, wide QRS rhythm in a patient with renal impairment should prompt a review of sodium channel blocker exposure. Medication history, renal function, serum drug concentration, and serial electrocardiograms should be integrated into the diagnostic approach when differentiating accelerated idioventricular rhythm from ventricular tachycardia.