Antitachycardia burst pacing for pleomorphic reentrant ventricular tachycardias associated with non-coronary artery diseases - A morphology specific programming for ventricular tachycardias

To study the role of antitachycardia burst pacing in patients with reentran t pleomorphic ventricular tachycardia (VT) associated with non-coronary art ery diseases, the efficacy of antitachycardia pacing and appropriate antita chycardia pacing cycle length were evaluated in each pleomorphic VT morphol ogy of seven patients. Seven patients were included in this study, Clinically documented pleomorph ic VTs were reproduced in an electrophysiologic study. For each VT, rapid v entricular pacing was attempted from the apex of the right ventricle at a c ycle length which was 20 ms shorter than that of VT and repeated after a de crement of the cycle length in steps of 10 ms until the VT was terminated o r accelerated. All 16 VTs could be entrained by the rapid pacing, and 13 of the 16 VTs (81 %) were terminated, whereas pacing-induced acceleration was observed in th e other 3 VTs of the 3 patients. VT cycle length (VTCL), block cycle length (BCL) which was defined as the longest VT interrupting paced cycle length, %BCL/VTCL and entrainment zone which was defined as VTCL minus BCL, varied in each VT morphology of each patient. In two patients, antitachycardia pa cing was effective in all VT morphologies and the maximum difference of the %BCL/VTCL among the pleomorphic VTs was less than 10 %. Thus, antitachycar dia pacing seemed to be beneficial for these patients. In the other 5 patie nts, a difference of more than 10 % in %BCL/VTCL was observed among the ple omorphic VT morphologies and/or at least one VT morphology showed pacing-in duced acceleration. Compared to the 13 terminated VTs, three accelerated VT s had a wide entrainment zone [160 +/- 34 vs 90 +/- 48 ms, p < 0.04] and sm all %BCL/VTCL [61 +/- 6 vs 77 +/- 11 %, p < 0.03]. In pleomorphic VTs associated with non-coronary artery diseases, responses to rapid pacing was not uniform, VT might be terminable or accelerated even in the same patient. We need to pay close attention when programming antit achycardia pacing in patients with pleomorphic VT.