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VT Induction (vt + induction)
Selected AbstractsMode of Induction of Ventricular Tachycardia and Prognosis in Patients with Coronary Disease: The Multicenter UnSustained Tachycardia Trial (MUSTT)JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2009JONATHAN P. PICCINI M.D. Introduction: Programmed stimulation is an important prognostic tool in the evaluation of patients with an ejection fraction ,40% after myocardial infarction. Many believe that ventricular tachycardia (VT) requiring 3 ventricular extrastimuli (VES) for induction is less likely to occur spontaneously and has less predictive value. However, it is unknown whether the mode of VT induction is associated with long-term prognosis. Methods and Results: We analyzed a cohort of 371 patients enrolled in MUSTT who had inducible monomorphic VT and who were not treated with antiarrhythmic drugs or an implantable cardioverter defibrillator during the trial. Patients in whom sustained VT was induced with 1 or 2 VES or burst pacing (single VES n = 15, double VES n = 127, burst n = 7, total n = 149) were compared with those in whom VT was induced with 3 VES (n = 222). Compared with the others, patients requiring 3 VES were closer to their most recent myocardial infarction (17 vs 51 months, P = 0.035) and showed a trend toward a lower ejection fraction (26% vs 30%, P = 0.057). VT requiring 3 VES had a shorter cycle length (240 vs 260 ms, P < 0.001). Despite these findings, there was no difference in the incidence of arrhythmic death or cardiac arrest (HR 1.02; 95% CI 0.69-1.51) or all-cause mortality (HR 1.03; 95% CI 0.76-1.39) according to the mode of induction in adjusted analyses. Conclusions: The prognostic significance of VT induced by 3 VES is similar to that of VT induced by 1 or 2 VES, or burst pacing, in patients with coronary disease and abnormal LV function. [source] The Effect of Induction Method on Defibrillation Threshold and Ventricular Fibrillation Cycle LengthJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2006ENDRE ZIMA M.D. Introduction: Since no clinical data are available on the comparison of the "shock on T-wave" and "high frequency burst" ventricular fibrillation (VF) induction modes during defibrillation threshold (DFT) testing, we aimed to compare these two methods during implantable cardioverter defibrillator implantation. Methods: The DFT was determined with a step-down protocol using biphasic, anodal polarity (100%, 40%, 20% voltage control) shocks. Patients were randomized: VF was induced by 50 Hz burst in group B (n = 45) and T-wave shock in group T (n = 41). The DFT was defined as the lowest energy level that terminated VF; confirmed DFT (DFTc) was defined as the minimal energy level that consecutively terminated VF twice. Success rate of DFTc was calculated during an intraindividual test for the alternate induction method. Results: A total of 546 episodes of VF were induced: n = 278 (B) vs n = 268 (T). Incidence of VT during inductions was 9.9% (B) vs 2.7% (T), P < 0.05. Neither the DFT, 8.8 ± 4.0 J (B) vs 9.7 ± 4.2 J (T), nor the DFTc, 10.6 ± 5.1 J (B) vs 10.8 ± 4.2 J (T), proved to be significantly different. A significant correlation was found between VF cycle length (CL) and the concomitant DFT (r = 0.298, P < 0.05) in group T only. Subgroup analysis of patients under chronic class III antiarrhythmic treatment showed no increase of the DFT in either group and significantly lower incidence of VT induction in group T regardless of antiarrhythmic treatment. Conclusion: The DFT and the VFCL proved to be independent of the VF induction method. The T-wave shock was more unlikely to induce VT during DFT testing. These results suggest that both methods are reliable in DFT determination, though T-wave shock application is a more reliable method for DFT testing. [source] Nonischemic Dilated Cardiomyopathy: Results of Noninvasive and Invasive Evaluation in 310 Patients and Clinical Significance of Bundle Branch BlockPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2008BEATRICE BREMBILLA-PERROT M.D. Background:The survival of patients with idiopathic dilated cardiomyopathy (IDCM) at III and IV stages of New York Heart Association (NYHA) is decreased in those with a bundle branch block (BBB) compared to those without BBB. Less is known on the prognosis of patients at earlier stages of NYHA and who had a left BBB (LBBB) or right BBB (RBBB). We sought to evaluate the prevalence and the clinical significance of LBBB or RBBB in patients with IDCM and classes I and II of NYHA. Methods:Clinical data, noninvasive, and invasive studies were consecutively collected in 310 patients, with IDCM, followed up to 4.8±3.7 years. Results:Seventy-six patients (25%) had LBBB, 21 (7%) had RBBB, and 212 had no BBB. Patients with BBB were older than other patients (P < 0.009). Left ventricular ejection fraction (LVEF) was lower in LBBB than in RBBB and other patients (P < 0.05). Syncope was more frequent in BBB than in absence (P < 0.05). Incidence of spontaneous ventricular tachycardia (VT) and atrial fibrillation, VT induction, total cardiac events, and sudden death were similar in the presence or absence of BBB. Deaths by heart failure and heart transplantations tended to be more frequent in BBB than in absence. Conclusions:LBBB was present in 25% of patients with IDCM; RBBB was rare. Patients with BBB were older and had more frequent syncope than patients without BBB; LVEF was lower in LBBB than in RBBB or in absence of BBB. BBB did not increase the risk of spontaneous VT, VT induction, or sudden death, and tended to increase deaths by heart failure and the indications of heart transplantation. [source] Are Routine Arrhythmia Inductions Necessary in Patients with Pectoral Implantable Cardioverter Defibrillators?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000MICHAEL GLIKSON M.D. Routine Arrhythmia Inductions in Patients with ICDs. Introduction: The value of ventricular arrhythmia inductions as part of routine implantable cardioverter defibrillator (ICD) follow-up in new-generation pectoral ICDs is unknown Methods and Results: We performed a retrospective analysis of a prospectively collected database analyzing data from 153 patients with pectoral ICDs who had routine arrhythmia inductions at predismissal, and 3 months and 1 year after implantation. Routine predismissal ventricular fibrillation (VF) induction yielded important findings in 8.8% of patients, all in patients with implantation defibrillation threshold (DFT) , 15 J or with concomitant pacemaker systems. At 3 months and 1 year, routine VF induction yielded important findings in 5.9% and 3.8% of tested patients, respectively, all in patients who had high DFT on prior testing. Ventricular tachycardia (VT) induction at predismissal, and 3 months and 1 year after implantation resulted in programming change in 37.4%, 28.1%, and 13.8% of tested patients, almost all in patients with inducible VT on baseline electrophysiologic study and clinical episodes since implantation. Conclusion: Although helpful in identifying potentially important ICD malfunctions, routine arrhythmia inductions during the first year after ICD implantation may not be necessary in all cases. VF inductions have a low yield in patients with previously low DFTs who lack concomitant pacemakers. VT inductions have a low yield in patients without baseline Inducible VT and in the absence of clinical events. Definite recommendations regarding patient selection must await larger prospective studies as well as consensus in the medical community about what comprises an acceptable risk justifying avoidance of the costs and inconveniences of routine arrhythmia inductions. [source] | ||||||||||