Arrhythmia Diagnosis Following an ICD Shock

A 70 year old male with coronary artery disease, severe left ventricular dysfunction (LVEF 20%), first degree AV block and underlying QRS of 154 msec underwent upgrade of an existing dual chamber ICD system with a Medtronic Insync Model 7272. The device was programmed to provide atrial synchronized biventricular pacing in the DDD mode. He experienced significant improvement in heart failure symptoms following cardiac resynchronization therapy. His ICD was programmed for single zone detection in the VF zone at 182 bpm with first shock therapy of 24J. Pacing was programmed in the DDD mode with lower rate limit of 70 and upper rate limit of 120ppm