Intradevice Interaction in a Dual Chamber Implantable Cardioverter Defibrillator Preventing Ventricular Tachyarrhythmia Detection

Intradevice Interaction in Dual Chamber ICD. Failure to detect ventricular tachycardia and/or ventricular fibrillation by implantable cardioverter defibrillators (ICDs) is a rare but serious problem. We report a case of failure to detect an episode of indueed ventricular tachycardia by a dual cbamber ICD, due to abbreviation of ventricular detection window secondary to programmed pacing parameters and a rate‐smoothing algorithm. In this patient, the intradevice interaction was corrected by programming rate‐smoothing off. This report highlights the potentially lethal consequences of critical timing relationships among the pacing function, arrhythmia detection, and the characteristics of the arrhythmia when using a modern dual chamber ICD. Physicians responsible for patients with ICDs must be aware of such interactions.