136-47: Fragmented QRS and mortality risk in patients with left ventricular dysfunction

Abstract

Background: Fragmented QRS (fQRS) has been shown to predict cardiac events in select patient populations. Whether fQRS improves patient selection for primary prevention patients eligible for implantable cardioverter-defibrillator (ICD) therapy remains unknown. Methods: It was a prospective study including 142 patients with left ventricular dysfunction (ejection fraction < or =35%) representing both ischemic and nonischemic etiology. the presence of fQRS on ECG was assessed using standardized criteria. The association between fQRS and all-cause and arrhythmic mortality was evaluated overall and stratified by ICD status using multivariable Cox regression models, adjusted for demographic, clinical, and treatment variables. Results: Fragmented QRS was present in 46 (32.4%) patients, and there were 32 (22.5%) deaths during a mean follow-up of 10 + /-7 months. Rates of all-cause mortality did not differ between the fQRS+ (18.4%) and fQRS- (23%) groups; adjusted hazard ratio, 0.88; 95% confidence interval, 0.63–1.22; P = 0.43. Additionally, rates of arrhythmic mortality were similar between the fQRS+ (8.7%) and fQRS- (10.7%) groups: adjusted hazard ratio, 0.77; 95% confidence interval, 0.49–1.31; P = 0.38. Subgroup analyses found no association between fQRS and mortality when the study was further stratified by ICD status, etiology of left ventricular dysfunction, wide (>/ = 120 ms) versus narrow (<120 ms) QRS duration, or fQRS myocardial territory. Conclusions: In this prospective study of patients with left ventricular dysfunction, the presence of fQRS on ECG was not associated with a higher risk of either all-cause or arrhythmic mortality. These findings do not provide evidence that fQRS would be effective in risk stratifying primary prevention patients eligible for ICD therapy.