960-84 Ramdomized Prospective Comparison of Four Burst Pacing Algorithms for Spontaneous Ventricular Tachycardia

Burst antitachycardia pacing (ATP) is higly efficacious for termination of monomorphic ventricular tachycardia (MVT). Since several pacing sequences are usually programmed as a single therapy. optimal programming is presently unknown. In 40 patients (P) with MVT and a 3rd generation AICD, 4 burst ATP were prospectively compared (as afirst single ATP) during followup in a randomized design crossing over every 2–3 months. Burst ATP modes (A to D) were defined by pacing cycle length (PCL, as % of VTCL) and number of beats (No B) (Table). A second ATP zone was programmed in a non selected way in all patientsResults (Table)374 episodes (317 considered MVT) received ATP therapies in 23 patients. RR intervals could be retrieved for MVT-CL analysis in 168 episodes. Succes rate of combined first (randomized) and second (non selected) therapies was 92%. Acceleration rate estimation was 2%.TherapyABCDglobalpPCL/No B91/781/791/1581/15AllVT68%46%85%61%69%<0.001VTCL < 350*82%14%44%38%47%0.03VTCL> 350°73%100%91%86%90%ns*Cl < 350: group of Mvr with Cl < 350ms°Cl > 350: Mvr with Cl > 350msConclusions1. Efficacy of the tested burst pacing modes differs significantly, at least in fast VT. 2. Contrary to what could be expected. “less agressive” bursts seem to be more efficacious, even in fast VT