Related Experiment Video
Updated: May 5, 2026

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Case report: Masked premature ventricular contractions and Intradevice interaction causing ventricular Arrythmias
Aravinthan Vignarajah1, Jose Aguilera2, Justin Z Lee2
1Department of Internal Medicine, Cleveland Clinic Fairview Hospital, Cleveland, OH, USA.
Abstract:
An implantable cardioverter-defibrillator (ICD) intended to prevent malignant arrhythmias can, in rare cases, precipitate them. We report a 44-year-old man with cardiac sarcoidosis who suffered recurrent polymorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) due to an intradevice timing interaction. Premature ventricular contractions (PVCs) fell within the ICD's post-atrial pacing ventricular blanking period and went undetected ("masked"), resulting in ventricular pacing during the vulnerable period (R-on-T), which triggered VT/VF. Reprogramming the device from DDD to VVI mode prevented further arrhythmias. This case highlights the importance of individualized ICD programming to avoid device-induced arrhythmias.
Related Concept Videos
Mechanism of Cardiac Arrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Dysrhythmias II: Classification of Tachyarrhythmias
Dysrhythmias V: Evaluating Dysrhythmias
Dysrhythmias VI: Management of Dysrhythmias
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

