- Brain natriuretic peptide (BNP) is a powerful predictor of mortality in patients with left ventricular dysfunction. Since malignant ventricular arrhythmias such as sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) are a major cause of death among those patients, we postulated that BNP levels can predict their long-term occurrence. To study the association between malignant ventricular arrhythmias and BNP level over a long term follow-up. We prospectively followed 94 patients with ischemic heart disease and left ventricular dysfunction, all implanted with an implantable cardioverter defibrillator (ICD). BNP level was measured at baseline and ICD interrogation and clinical status were recorded at 6 months intervals for a median of 3.5 years. Patients with BNP levels in the highest quartile experienced significantly more arrhythmic events than those at the lower three quartiles (OR 2.2, 95% C.I 1.2-4.2). In a multivariate analysis only BNP level predicted arrhythmic events. Among patients implanted for primary prevention of sudden cardiac death, BNP at the lowest quartile significantly predicted low event rate. While high BNP level is predictive of malignant ventricular arrhythmias, low levels among patients implanted for primary prevention can identify a low risk subgroup for which the ICD might be of borderline therapeutic benefit.