Related Experiment Videos
[Sustained ventricular tachycardia: low-energy transcatheter internal cardioversion. Efficacy, reliability and
Abstract:
The aim of this study is to evaluate the efficacy, reliability and patient tolerance of low-energy transcatheter intracardiac cardioversion in the treatment of Sustained Ventricular Tachycardia (VT), and to compare this method to ventricular burst. For this purpose 11 patients (pts) (10 M, 1 F, mean age 50.1 yrs, range 24-72) with 18 different types of VT (17 induced during Endocavitary Electrophysiological Study (EES), 1 "clinical"), who all underwent EES all but 1 with organic heart disease, were first treated by transcatheter intracardiac cardioversion and then, if possible, with ventricular burst at 125%-150% of VT rate. The Medtronic Cardioverter 5350 and the Medtronic catheter 6880 were used. The following results were obtained: transcatheter intracardiac cardioversion terminated 9/18 types of VT (8 types at least 3 times) in 6 pts. Cardioversion threshold was on average 1.31 J (range: 0.14-5). Transcatheter intracardiac cardioversion failed to terminate 9/18 types of VT (in 5 pts); VT acceleration or ventricular fibrillation occurred in 6/9 types. The mean cycle length of successfully cardioverted VT (382 +/- 61 msec.) was significantly longer (p = 0.05) than that of not successfully cardioverted VT (284 +/- 83 msec.) and of the VT in whom an acceleration or a degeneration into ventricular fibrillation was observed (240 +/- 55 msec.). In 4 pts it was necessary to use external DC shock and in 4 supraventricular hyperkinetic arrhythmia was induced. All pts complained of considerable discomfort at shocks greater than or equal to 0.5 J. In all the 7 types of successfully cardioverted VT as well as in 3 out of the 4 types of not successfully cardioverted VT in which it was possible to test ventricular burst, this latter proved to be effective. These results indicate that: the efficacy of transcatheter intracardiac cardioversion is not great at least in our pts (50%); moreover, the transcatheter intracardiac cardioversion is affected by a high incidence of acceleration of VT and degeneration into ventricular fibrillation (33.3%) and by the induction of supraventricular hyperkinetic arrhythmia (22.2%). Patient discomfort appears to be a major limitation to transcatheter intracardiac cardioversion. The VT cycle length is determinant for the success of the transcatheter intracardiac cardioversion and for the induction either of an acceleration of VT or of a degeneration into ventricular fibrillation (which are observed only in VT with cycle length less than or equal to 300 msec.).(ABSTRACT TRUNCATED AT 400 WORDS)