The utility of fragmented QRS complexes to predict significant intraventricular dyssynchrony in nonischemic dilated cardiomyopathy patients with a narrow QRS interval

BACKGROUND: Fragmented QRS complexes in the electrocardiograms (ECGs) of patients with coronary artery disease are associated with adverse cardiac events. However, there are limited data on its predictive usefulness in patients with nonischemic dilated cardiomyopathy. Left ventricular dyssynchrony is common in heart failure patients who have wide QRS intervals, but its frequency in patients with narrow QRS intervals is uncertain. OBJECTIVES: To investigate the relationship between fragmented QRS complexes and intraventricular dyssynchrony in patients with nonischemic dilated cardiomyopathy in sinus rhythm. METHODS: Sixty nonischemic dilated cardiomyopathy patients with sinus rhythm and narrow QRS intervals were recruited. Forty patients had a fragmented QRS in their basal ECG, and 20 patients did not have a fragmented QRS. Patients were analyzed for correlation between fragmented QRS complexes and intraventricular dyssynchrony. RESULTS: The maximal difference in time to the peak myocardial systolic velocity between any two left ventricular segments (Max-ASE Sys), and maximal difference between Max-ASE Sys and the mean value of all segments (Max-ASE to Mean Sys) were significantly higher in patients with fragmented QRS complexes (P=0.001 and P=0.003, respectively). Seventy-two per cent of the patients with fragmented QRS complexes had significant left ventricular dyssynchrony; 15% of patients without fragmented QRS complexes had significant left ventricular dyssynchrony (P<0.0001). The presence of fragmented QRS complexes in leads corresponding to the specific ventricular segment in basal ECG was found to detect intraventricular dyssynchrony with 90.6% sensitivity (negative predictive value of 85%). CONCLUSION: Fragmentation in the resting ECG is associated with significant intraventricular dyssynchrony in patients with nonischemic cardiomyopathy, narrow QRS and sinus rhythm. Fragmentation in ECG might be useful in identifying patients who could benefit from cardiac resynchronization therapy.