A Prospective, Multicenter, Randomized Controlled Trial Comparing Atrial Sensing ON-mode of VDD Implantable Cardioverter Defibrillator(ICD) to Atrial Sensing OFF-mode of VDD ICD in Detecting Atrial Fibrillation(Smart-Control Study)

Implantable cardioverter defibrillators(ICD) therapy has been shown to reduce sudden cardiac death and improve survival in cardiac arrest survivors as well as in heart failure patients with left ventricular dysfunction.

Atrial fibrillation (AF) is commonly found in ICD implantation patients up to 50%. AF is an independent predictor of mortality, inappropriate shock, and embolic events. Therefore, early detection of AF in patients with ICD is essential for improving the quality of life and overall prognosis of the patients.

Conventional ICDs consist of a single chamber (SC) ICD with a lead only in the right ventricle (RV) and dual chamber (DC) ICD with each lead in the right atrium (RA) and RV. SC ICD has the advantage of shorter procedure time, lower cost compared to DC ICD. In contrast, DC ICD has the advantage of being able to monitor atrial arrhythmic events, but complication rates were higher and additional cost and longer procedure time are usually required than SC ICD. Sixty percent of ICD implantation patients who have are SC ICD Recently, a unique ICD lead with atrial sensing ring capable of monitoring the atrial electrical signals has been developed [Intica 7 VR-T DX ICD (Biotronik., Germany)]. Therefore, turning off the atrial sensing function makes it functionally the same as SC ICD whereas turning on makes it function similar to DC ICD without additional cost and procedure time.

Therefore, Detection of AF could be made earlier with VDD ICD versus conventional SC ICD without atrial sensing capability, providing a better chance to improve the prognosis of ICD patients. However, no study exists which shows whether VDD ICD is better for detecting atrial tachyarrhythmia than conventional SC ICD. Therefore, we designed a multicenter prospective randomized study comparing the AF diagnostic efficacy of VDD ICD (with atrial sensing 'ON') against conventional SC ICD. As the second phase, we also plan to compare inappropriate therapy rate according to atrial sensing status of VDD ICD.