Inappropriate Shocks Caused by Implantable Cardioverter-Defibrillator Lead Malposition.

A 57-year-old man with ischemic cardiomyopathy underwent dual-chamber, dual-coil implantable cardioverter-defibrillator (ICD) implantation in 2016 for primary prevention of sudden cardiac death. Device programming included ventricular tachycardia detection at > 171 beats/min and ventricular fibrillation (VF) detection at > 200 beats/ min. Two years later, he presented with multiple painful ICD shocks occurring over a one-week period. He was hemodynamically stable. Electrocardiography demonstrated sinus rhythm with findings consistent with prior anterior myocardial infarction. Transthoracic echocardiography revealed a dilated left ventricle with reduced systolic function (ejection fraction, 30%), and a left atrial anteroposterior diameter of 40 mm. Device interrogation on admission demonstrated DDD mode with normal atrial sensing and pacing parameters, ventricular sensing amplitude of 2.2 mV, pacing amplitude of 3.0 V, pacing impedance of 380 Ω, absence of ventricular myocardial