Abstract 14494: Once You 1c It, You Can’t Unsee It: A Case of Flecainide Toxicity

Abstract

Introduction: Flecainide is a class 1c antiarrhythmic commonly used for the treatment of atrial and ventricular arrhythmias in the absence of underlying structural heart disease. The significant proarrhythmic effects of the drug warrant familiarity with the drug and its toxicity. Flecainide overdose, whether intentional or iatrogenic, is a life threatening emergency with mortality rates as high as 22.5%. We present a case of intentional flecainide overdose and its management. Case: A 78-year-old man with a history of heart failure, paroxysmal atrial fibrillation on flecainide, presented to a local ED after a suicide attempt. He was initially hemodynamically stable and a 12-lead EKG revealed a wide-QRS bradyarrhythmia (See figure 1). Electrolyte panel showed normal potassium and pH. During transport to our tertiary cardiac intensive care unit, the patient declined and was critically ill on arrival. The diagnosis of flecainide toxicity was suspected and therapy was initiated on arrival. Despite therapy with sodium bicarbonate and fat emulsion, the patient continued to decline. Renal replacement therapy was started and the patient was evaluated for mechanical circulatory support. Ultimately, the patient’s family elected for palliative extubation. The patient’s flecainide level returned more than four times above the therapeutic range. Discussion: This case highlights the importance of a high index of suspicion when faced with a wide-QRS arrythmia in a patient with suspected antiarrhythmic overdose. The persistence of these rhythms after correction of acid-base abnormalities and electrolyte derangements should prompt aggressive, empiric treatment of potential overdose. The presence of electromechanical dyssynchrony in this context is an ominous sign and should prompt simultaneous evaluation for biventricular mechanical circulatory support concomitant with medical therapy for suspected overdose. Figure 1