Role of antitachycardia pacing in patients with third generation cardioverter defibrillators.

The most effective antitachycardia pacing (ATP) mode is still a matter of debate. Randomized prospective testing of 3 different ATP modes was performed in 65 patients (pts) prior to and after cardioverter defibrillator implantation (Ventak PRx 36 pts, Cadence V 100 29 pts). All 3 ATP modes included 4 stimulation attempts with 4-7 adaptive scanning burst pulses. Adaptive burst coupling interval was 75% in mode A, 81% in mode B and 69% in mode C. Autodecremental scanning within bursts was 8 msec in all, decremental scanning between bursts was 8 msec in modes B and C. Each ATP mode had to be tested 3 times; all 3 ATP modes were randomly applied to each pt. During preoperative testing 91 of 133 VT episodes (68%) could be terminated by ATP. Termination was achieved in 68% with mode A, 68% with mode B and 73% with mode C. During predischarge testing, 251 VTs were induced and ATP was successful in 147 VTs (59%). Termination rate was 56% with mode A, 68% with mode B and 50% with mode C. During the mean follow-up of 12 months, 2301 arrhythmia episodes (AE) occurred. ATP was performed in 2097 AE (91%) and successful in 1920 AE (92%). Acceleration of VT occurred in 65 AE (3%) and unsuccessful ATP was observed in 112 AE (5%). It is concluded that ATP in general is highly effective in pts with sustained VT. None of the tested ATP modes, however, proved to be superior to the other.