Mode of induction of ventricular tachycardia and prognosis in patients with coronary disease: the Multicenter UnSustained Tachycardia Trial (MUSTT).
BACKGROUND
Programmed stimulation is an important prognostic tool in the evaluation of patients with an ejection fraction <or=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.


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.
Piccini
Jonathan P
JP
Duke Clinical Research Institute, Durham, North Carolina, USA.
Hafley
Gail E
GE
Lee
Kerry L
KL
Fisher
John D
JD
Josephson
Mark E
ME
Prystowsky
Eric N
EN
Buxton
Alfred E
AE
D000368:Aged; D015331:Cohort Studies; D003327:Coronary Disease / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*