Assessment of Left Ventricular Dyssynchrony in Patients With Conduction Delay and Idiopathic Dilated Cardiomyopathy

OBJECTIVES This study sought to compare tissue Doppler imaging (TDI) with velocity-encoded (VE) magnetic resonance imaging (MRI) for left ventricular (LV) dyssynchrony assessment. BACKGROUND Cardiac resynchronization therapy (CRT) is proposed for patients with heart failure, depressed LV function, and a wide QRS complex. Selection is based mainly on electrocardiogram criteria, but recent data suggest that intraventricular dyssynchrony may be preferred for selection. An LV dyssynchrony can adequately be assessed with TDI, but this has not been compared directly with other imaging modalities. A VE MRI potentially allows direct myocardial wall motion measurements similar to TDI. METHODS Twenty patients with heart failure, systolic LV dysfunction, and a wide QRS complex were included, as well as 10 normal individuals with normal QRS duration and LV function. The TDI and VE MRI data were acquired to study intraventricular dyssynchrony. RESULTS Left ventricular dyssynchrony was not observed in normal individuals (mean dyssynchrony 2 15 ms on TDI; mean 5 17 ms on MRI, p NS). In patients, mean LV dyssynchrony was 55 37 ms on TDI; 49 38 ms on MRI (p NS). Good correlation between both modalities was observed (linear regression TDI 0.99 MRI 5, n 30, r 0.98, p 0.01). The MRI showed a small, nonsignificant underestimation of 5 8 ms compared with TDI. Agreement between MRI and TDI for classification according to severity of LV dyssynchrony (minimal, intermediate, and extensive) was excellent ( SE 0.96 0.07, p 0.01) with 95% of patients classified identical. CONCLUSIONS Both MRI and TDI yield comparable information on LV dyssynchrony; MRI is useful in the selection of patients for CRT. (J Am Coll Cardiol 2006;47:2042–8) © 2006 by the ublished by Elsevier Inc. doi:10.1016/j.jacc.2006.01.058