In-hospital versus out-of-hospital presentation of life-threatening ventricular arrhythmias predicts survival - Results from the AVID Registry

OBJECTIVES This study describes the outcomes of patients from the Antiarrhy thmics Versus Implantable Defibrillators (AVID) Study Registry to determine how the location of ventricular arrhythmia presentation influences surviva l. BACKGROUND Most studies of cardiac arrest report outcome following out-of-h ospital resuscitation. In contrast, there are minimal data on long-term out come following in-hospital cardiac arrest. METHODS The AVID Study was a multicenter, randomized comparison of drug and defibrillator strategies to treat life-threatening ventricular arrhythmias . A Registry was maintained of all patients with sustained ventricular arrh ythmias at each study site. The present study includes patients who had AVI D-eligible arrhythmias, both randomized and not randomized. Patients with i n-hospital and out-of-hospital presentations are compared. Data on long-ter m mortality were obtained through the National Death Index. RESULTS The unadjusted mortality rates at one- and two-year follow-ups were 23% and 31.1% for patients with in-hospital presentations, and 10.5% and 1 6.8% for those with out-of-hospital presentations (p < 0.001), respectively . The adjusted mortality rates at one- and two-year follow-ups were 14.8% a nd 20.9% for patients with in-hospital presentations, and 8.4% and 14.1% fo r those with out-of-hospital presentations (p < 0.001), respectively. The a djusted long-term relative risk for in-hospital versus out-of-hospital pres entation was 1.6 (95% confidence interval [CI] 1.3-1.9). CONCLUSIONS Compared with patients with out-of-hospital presentations of li fe-threatening ventricular arrhythmias not due to a reversible cause, patie nts with in-hospital presentations have a worse long-term prognosis. Becaus e location of ventricular arrhythmia presentation is an independent predict or of long-term outcome, it should be considered as an element of risk stra tification and when planning clinical trials. (J Am Coll Cardiol 1999;34:11 11-6) (C) 1999 by the American College of Cardiology.