['We sought to study the association between brain natriuretic peptide (BNP) levels and the occurrence of ventricular arrhythmias in patients with left ventricular dysfunction (LVD) and an implantable cardioverter defibrillator (ICD).', 'This was a prospective study of consecutive, stable, ambulatory patients with moderate and severe ischemic LVD and an ICD. A plasma BNP level was obtained at recruitment. Patients were evaluated every 3-6 mo for a minimum of 1 y. The primary end point was the occurrence of malignant ventricular arrhythmia or sudden cardiac death (SCD).', 'The cohort consisted of 94 subjects (6 women) with a mean +/- standard deviation (SD) age of 69 +/- 10 y. The ICD implantation indication was primary and secondary prevention of SCD in 49% and 51% of subjects, respectively. A primary end point occurred in 27 patients (29%), and was more frequent in symptomatic heart failure patients and those implanted for secondary prevention of SCD. The median BNP level was significantly higher among patients who experienced an end point (191 pg/ml versus 142 pg/ml, p = 0.03). After controlling for New York Heart Association heart failure class and ICD implantation indication, the odds ratio (OR) for experiencing an adverse outcome among the upper BNP quartile versus all others was 3.5 (95% confidence interval [CI]: 1.2-10.2). Among patients implanted for primary prevention of SCD, none of the patients in the lower BNP quartile (BNP < 91 pg/ml) experienced an adverse outcome.'] Do b-type natruiretic peptide levels stratify the risk for arrhythmia among implantable cardioverter defibrillator patients?