[Idiopathic ventricular fibrillation: from a collection of clinical cases to a prospective evaluation. The U-CARE Steering Committee. Unexplained Cardiac Arrest Registry of Europe].

BACKGROUND: The primary aim of U-CARE (Unexplained Cardiac Arrest Registry of Europe) is to collect clinical information on survivors about a documented episode of idiopathic ventricular fibrillation (IVF) and to follow these patients (pts) prospectively to acquire information on 1) recurrence of malignant arrhythmias or cardiac arrest, 2) development of a previously non obvious organic heart disease, 3) potential difference in outcome in pts treated with different drugs or devices.

METHODS AND RESULTS: Within April 15th, 1994, eighty-six pts have been enrolled, 65 males and 21 females. The mean age at the time of the first cardiac arrest was 35 +/- 15 years. Clinical evaluation revealed "minor" functional or anatomical abnormalities in 14 subjects and they were excluded from the analysis. In the remaining 72 pts, no abnormalities were found at echocardiogram, Holter, angiography, exercise stress test. At the electrophysiologic study 35/68 pts were inducible. Thirty-eight pts received pharmacologic therapy, 28 an implantable defibrillator (ICD), three pts received both an ICD and drug therapy and three were left untreated. Follow-up data are available for 37 pts with a mean follow-up of 4.4 +/- 2.6 years. No patient had evidence of structural heart disease. Twenty-three pts remained asymptomatic, 12 (32%) had a recurrence of syncope or cardiac arrest: three died suddenly and 2 were defibrillated by the ICD. This study that represents the largest experience in IVF, shows: 1) all patients remained free from any organic heart disease at follow-up, 2) they have a high risk of recurrence of major arrhythmic events.

CONCLUSIONS: An ICD implant would be appropriate in this population, at least until data on the efficacy of the pharmacologic therapy will be available.