BACKGROUND: -Patients with a high ventricular rate during atrial fibrillation (AF) are at increased risk of receiving inappropriate implantable cardioverter defibrillator (ICD) shocks. The objective was to demonstrate the feasibility of high frequency atrioventricular-nodal stimulation (AVNS) to reduce the ventricular rate during AF to prevent inappropriate ICD shocks.
METHODS AND RESULTS: -Patients with a new atrial lead placement as part of a CRT-D implant and a history of paroxysmal or persistent AF were eligible. If proper atrial lead position was confirmed, AVNS software was uploaded to the CRT device, tested and optimized. AVNS was delivered via a right atrial pacing lead positioned in the posterior right atrium. Software allowed initiation of high frequency bursts triggered on rapidly conducted AF. Importantly, the efficacy was evaluated during spontaneous AF episodes between 1 and 6 months after implant. Forty-four patients were enrolled in 4 centers. Successful atrial lead placement occurred in 74%. Median implant time of the AVNS lead was 37 minutes. In 26 (81%) patients, manual AVNS tests increased the ventricular interval by > 25%. Between 1 and 6 months, automatic AVNS activations occurred in 4 patients with rapidly conducted AF, and in 3 patients, AVNS slowed the ventricular rate out of the ICD shock zone. No adverse events were associated with the AVNS software.
CONCLUSIONS: -The present study demonstrated the feasibility of implementation of AVNS in a CRT-D system. AVNS increased ventricular interval > 25% in 81% of patients. AVNS did not influence the safety profile of the CRT-D system.
2015. Vol. 8, no 3, 562-568 p.