Differences in inducibility and prognosis of in-hospital versus out-of-hospital identified nonsustained ventricular tachycardia in patients with coronary artery disease: Clinical and trial design implications

OBJECTIVES The goal of this study was to describe the influence of the clin ical setting (in-hospital vs. out-of-hospital) in which nonsustained ventri cular tachycardia (NSVT) is discovered on the rate of inducibility of susta ined ventricular tachycardia (VT), arrhythmic events and survival in patien ts with coronary artery disease (CAD) and left ventricular (LV) dysfunction . BACKGROUND In-hospital presentation of sustained VT is independently associ ated with lower long-term overall survival. The impact of the clinical sett ing in which NSVT is documented is unknown. METHODS In the Multicenter Unsustained Tachycardia. Trial (MUSTT), designed to assess the benefit of randomized antiarrhythmic therapy guided by elect rophysiologic testing in patients with asymptomatic NSVT, CAD and LV dysfun ction, eligible patients were enrolled irrespective of the setting in which the index arrhythmia was discovered. In this retrospective analysis, we co mpared the rate of VT inducibility and outcome of MUSTT-enrolled patients w ith in-hospital versus out-of-hospital presentation of NSVT. RESULTS Monamorphic sustained VT was induced in 35% and 28% of the patients whose index NSVT occurred in-hospital and out-of-hospital, respectively (a djusted p = 0.006). Cardiac arrest or death due to arrhythmia at two- and f ive-year follow-ups were 14% and 28% for untreated patients with in-hospita l-identified NSVT and 11% and 21% for the out-of-hospital group (adjusted p = 0.10). Overall mortality rates at two- and five-year follow-ups were 24% and 48% for inpatients and 18% and 38% for outpatients (adjusted p = 0.018 ). In patients randomized to antiarrhythmic therapy, there was no significa nt interaction between patient 4 status (in-hospital vs. out-of-hospital) a nd treatment impact on the rates of total mortality (p = 0.98) and arrhythm ic events (p = 0.08). CONCLUSIONS In patients with CAD and impaired LV function, asymptomatic NSV T identified in hospital, compared with that identified out-of-hospital, is associated with a higher rate of induction of sustained VT and overall mor tality. Therefore, in similar patients, the clinical setting in which NSVT is discovered should be taken into account when formulating patient risk, t reatment and clinical trial design. (C) 2001 by the American College of Car diology.