Prevalence of dyssynchrony derived from echocardiographic criteria in heart failure patients with normal or wide QRS duration

Objective To evaluate the prevalence of dyssynchrony in heart failure patients with either normal or prolonged QRS duration using conventional echocardiographic technique and tissue Doppler imaging. Methods Sixty heart failure patients with idiopathic dilated cardiomyopathy (30 with wide QRS complex, 30 with normal QRS complex) underwent standard echocardiography and tissue Doppler imaging examinations. Difference between left and right ventricular pre-ejection intervals of more than 40 ms was considered a marker of interventricular dyssynchrony. Intraventricular dyssynchrony was defined as a delay of 60 ms between the time to peak velocities of the septum and left ventricular lateral wall. Patients who have either intra-or inter-ventricular dyssynchrony were defined as with cardiac dyssynchrony. Results Dyssynchrony was observed in 7(23.3%) heart failure patients with normal QRS complex versus 26(86.7%) patients with wide QRS complex. There was a significant difference between the prevalence of dyssynchrony derived from echo criteria in two groups (P0.01). No relation existed between QRS duration and dyssynchrony (P=0.112). Conclusion Although patients with wide QRS complex had a high prevalence of dyssynchrony, yet some still had good cardiac synchronicity. Moreover, dyssynchrony also existed in a small percentage of heart failure patients with normal QRS duration.