Early Recognition and Management of Flecainide Toxicity: A Case Report and Literature Review.

Flecainide acetate is classified as a class IC antiarrhythmic medication according to the Vaughan-Williams classification, primarily used to manage both ventricular and supraventricular tachycardia. It is commonly employed for pharmacological cardioversion of atrial fibrillation (AF) and is frequently used in the "pill-in-the-pocket" approach for on-demand rhythm control. Despite its efficacy, flecainide is associated with significant adverse effects, including cardiac arrest, dysrhythmias, and heart failure. The presence of renal impairment or drug-drug interactions can exacerbate these side effects. Although rare, the risk of cardiogenic shock in flecainide toxicity is noteworthy. Given the potential for life-threatening hemodynamic compromise, often manifesting as ventricular arrhythmias like ventricular tachycardia or ventricular fibrillation, emergency physicians should maintain a high index of suspicion for flecainide toxicity in patients using the drug. Early recognition is crucial, as delayed diagnosis and treatment can be fatal. This report presents a case of an elderly female patient who presented with wide QRS complex tachycardia and hyponatremia. Her baseline rhythm was restored without the need for cardioversion, defibrillation, or pacing following the administration of sodium bicarbonate.