Unique Tachycardia Recorded on a Cardiac Implantable Electronic Device: What is the Mechanism?

In a 55-year-old man with nonischemic cardiomyopathy, a unique tachycardia was recorded on a dual-chamber implantable cardioverter defibrillator (St. Jude Medical [Abbott]) as an automatic mode switch episode. This case report discusses the mechanism of tachycardia, how it can be differentiated from similar rhythms, and its clinical implications. The report explores device limitations in managing such tachycardias and presents reprograming strategies to prevent recurrence. This case emphasizes the importance of careful analysis of device-mediated arrhythmias and appropriate programming.