Ventricular Standstill Following Intravenous Erythromycin and Borderline Hypokalemia

Ventricular standstill (VS) is a potentially fatal arrhythmia that is usually associated with syncope, if prolonged and is rarely asymptomatic([1]). Its mechanism involves either a lack of supraventricular impulse or an interruption in the transmission of these signals from the atria to the ventricles, resulting in a sudden loss of cardiac output([2]). Although rare, ventricular arrhythmias have been associated with intravenous (IV) erythromycin. However, to our knowledge, VS has not been reported following the administration of IV erythromycin. The Authors describe a rare case of asymptomatic VS and subsequent third-degree atrioventricular block, following the administration of IV erythromycin in a 49-year-old woman with borderline hypokalemia. Through this case, the Authors highlight the importance of cardiac monitoring and electrolyte replacement when administering IV erythromycin, as well as discuss several other mechanisms that contribute to ventricular arrhythmias. LEARNING POINTS: Intravenous erythromycin is associated with prolongation of the QTc interval and ventricular arrhythmias. Ventricular standstill is a rare but potentially fatal arrhythmia, and may have an association with the administration of intravenous erythromycin. Cardiac monitoring in patients with baseline QTc prolongation and correction of electrolyte disturbances are important when administering intravenous erythromycin.