Difference in the efficacy of atrial antitachycardia pacing for suppression of ventricular arrhythmias

Background Intermittent atrial tachyarrhythmias (ATAs) are associated with ventricular arrhythmias (VAs), particularly in patients with left ventricular dysfunction. Little is known about the effect of atrial antitachycardia pacing (Reactive ATP [rATP]) on the reduction of VAs in patients with a shock device. Objectives We examined differences in the efficacy of rATP in the suppression of VAs in patients with a shock device. Methods Overall, among 589 consecutive patients with a shock device, we analyzed those with a history of intermittent ATAs and a cardiac resynchronization therapy device with defibrillator (CRTD, n=112) or an implantable cardioverter defibrillator (ICD, n=32). The study subjects were categorized into two groups based on availability of rATP; rATP group: 72 pts and No-rATP group: 72 pts). Primary outcome was VA events treated by ventricular ATP or shock, or lasted ≥30 seconds. Results During a median follow-up of 862 days, the rATP group (n=55) had a significantly lower risk of VAs compared with the no-rATP group (n=57) (log rank p=0.02); moreover, rATP was an independent negative predictor of VAs (hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.21–0.84, p=0.01) among patients with CRTD, whereas there was no significant difference between the rATP group (n=17) and the no-rATP group (n=15) among patients with ICD (HR: 0.59, 95%CI: 0.10–3.55, p=0.57). Conclusion Reactive ATP was significantly associated with a lower risk of VAs in patients with CRTD and intermittent ATAs, but not in patients with an ICD.