Antitachycardia pacing for rapid VT during ICD charging: A method to prevent ICD shocks

In patients with ICDs, rapid VTs are usually treated with shocks. It is unk nown, if antitachycardia pacing (ATP) delivered once for rapid VT during ca pacitor charging can avoid painful shocks without increasing the risk of sy ncope. In patients in whom rapid monomorphic VT (cycle length 300-220 ms) c ould be reproducibly induced during predischarge ICD testing, the success o f cardioversion (defibrillation threshold plus 10 J) and a single ATP attem pt (burst with 8 or 16 stimuli) was compared using a randomized crossover s tudy design. Consciousness of the patients was checked by the signal from a button constantly pushed by the patient. in 20 patients (ejection fraction 0.50 +/- 0.19) rapid VTs (253 +/- 26 ms) were reproducibly induced. A sing le burst successfully terminated 11 (55%) of 20 rapid VTs, 6 episodes could not be terminated with a single burst pacing and 3 VTs accelerated. Rapid VTs not terminated by ATP were significantly faster than those that could b e terminated (246 vs 258 ms, P = 0.026). Cardioversion (19 +/- 3 J) termina ted the VTs in all cases. No patient suffered syncope during rapid VTs. A s ingle ATP may terminate rapid VT with cycle lengths < 300 ms in 55% of pati ents without increasing the risk of syncope. Therefore, in rapid VTs one at tempt of ATP may be suitable as an additional therapy option during ICD cap acitor charging to avoid painful shocks without compromise of safety. Thus, future ICDs should implement the option of A TP during charging of capacit ors.