Abstract 8148: Optimal Number of Antitachycardia Pacing Sequences Associated with Successful Termination of Ventricular Tachyarrhythmias in ICD Patients
Introduction: Antitachycardia pacing (ATP) has been shown to be effective in terminating ventricular tachyarrhythmias painlessly in ICD patients. Similar success rates for various algorithms for ATP (e.g. Ramp vs Burst) have been described. However, the optimal number of ATP sequences that should be programmed to terminate VT without need for an ICD shock has not been widely studied. We aim to determine if the number of ATP sequences programmed correlated with successful termination of ventricular tachyarrhythmias without need for ICD shock.
Methods: All patients on follow up at National Heart Centre Singapore with available records of any appropriate ICD therapy within a 3 year period were recruited. Clinical characteristics, device programming and all recorded ventricular tachyarrhythmias were analysed.
Results: 375 VT events in 42 patients were analysed. Median age 59.5 years, median 4 years follow up. 54.7% had ICDs implanted for secondary prevention. Mean VT cycle length was 357ms+/-46ms(SD). Majority (91.6%) had ATP (majority 8 pulses at 88% coupling interval) programmed for VT zone tachycardias. Success rate of ATP with a single programmed ATP sequence was 50%, double sequence 67%, three 85%, four or more 67% - differences statistically significant (p=0.02). 3 or more ATP sequences was associated with reduced overall ICD shocks (p=0.04), inclusive of shocks for VF due to VT acceleration (5% of ATP episodes). There was one mortality in a patient programmed with 3 ATP sequences from unrelated metastatic sigmoid carcinoma.
Conclusions: In our study population, 3 ATP sequences appeared to be optimal in terminating VT with a concomitant reduction in appropriate but unnecessary shocks. Further studies in larger ICD populations are indicated.
- © 2011 by American Heart Association, Inc.