Background There are few data from community-based evaluations of outcomes after a life-threatening ventricular arrhythmia (LTVA). We evaluated patients' quality of life (QOL) and medical costs after hospitalization and treatment for their first episode of an LTVA. Methods We prospectively evaluated QOL by use of the Duke Activity Status Index (DASI), Medical Outcomes Study SF-36 mental health and vitality scales, the Cardiac Arrhythmia Suppression Trial (CAST) symptom scale, and resource use in patients discharged after a first episode of an LTVA in a managed care population of 2.4 million members. Results We enrolled 264 subjects with new cases of LTVA. Although functional status initially decreased compared with self-reports of pre-event functional status, both functional status and symptom levels improved significantly during the study period. These improvements were greater in patients receiving an implantable cardioverter defibrillator (ICD) than in patients receiving amiodarone. Ratings of mental health and vitality were not significantly different between the treatment groups and did not change significantly during follow-up. The total 2-year medical costs were higher for patients receiving an ICD than for patients receiving amiodarone, despite lower costs during the follow-up period for the patients receiving an ICD. Conclusions New onset of an LTVA has a substantial negative initial impact on QOL. With therapy, most patients have improvements in their QOL and symptom level, possibly more so after treatment with an ICD. The costs of treating these patients are very high. (Am Heart J 2002;144:404-12.)