Background: We recently reported that novel low-voltage Multi-Pulse Therapy (MPT) can effectively terminate atrial fibrillation (AF) in a first-in-human study. Because the study was performed in patients with paroxysmal AF and MPT tested on induced AF, it was unclear if AF terminations were due to MPT or spontaneous terminations.
Objective: To determine if there is causal relationship between MPT and AF terminations.
Methods: In patients undergoing AF ablation, AF was induced and MPT (up to 3 stages of far- and near-field stimulation pulses of varied duration and inter-pulse timing) delivered via temporary intracardiac leads positioned in the right or left atrium and the coronary sinus. Using Kaplan-Meier analysis, the effect of MPT on AF termination (n=12, 44 AF episodes) was compared to a retrospective control group (n=7, 18 AF episodes), where no therapy was delivered for 1 minute after AF induction.
Results: The MPT therapy arms had greater AF termination rates compared to the control arm (single MPT 72%, multiple MPT 73% vs. controls 22% at 60 seconds following AF induction (p=0.019 and p=0.008 respectively)), suggesting that MPT causally contributed to AF terminations. Multivariate analysis showed that MPT success was significantly related to time between AF induction and MPT delivery (p<0.001).
Conclusion: MPT terminated AF at significantly greater terminations rates than would be expected with spontaneous terminations, at voltages and energies which are significantly lower than required with conventional biphasic shocks. These results support further studies of the concept of implanted devices for early AF conversion to reduce AF burden, symptoms, and progression.