ABSTRACT
Echocardiographic parameters of mechanical dyssynchrony may improve patients selection for cardiac resynchronisation therapy in chronic heart failure. This study aimed to define the prevalence of inter, intra and atrio-ventricular dyssynchrony in heart failure patients with different QRS duration and to evaluate inter and intra-observer variability in collecting different echocardiographic dyssynchony parameters. Twenty patients with chronic heart failure of any origin, NYHA functional class II-III with LVEF < 40%, were evaluated by complete echocardiographic examination including tissue Doppler imaging [DTI] and Tissue Tracking. Three patients had an atrio-ventricular dyssynchrony with a mean left ventricular filling time to cardiac cycle of 33 +/- 5%. Six patients had an interventricular mechanical delay [IVMD] > 40 milliseconds, all of them had a QRS duration >/= 120 milliseconds. Overall, no statistically significant correlation was found between IVMD and QRS duration [r=0.35, p=0.4]. The mean septal to posterior wall-motion delay [SPWMD] was 83 +/- 64 ms. 7 patients had SPWMD >/= 130 ms. The baseline QRS duration did not correlate with SPWMD [p=0.7]. The mean LV dyssynchrony determined by deltaS-peak was 74 +/- 42 ms. Seven patients had LV dyssynchrony. Linear regression did not demonstrate a relation between QRS width and intraventricular dyssynchrony [p=0.34]. There was no concordance between intra-ventricular spatial or longitudinal dyssynchrony determined by DTI method and by Tissue Tracking [p=0.3 and 0.6 respectively]. The intraobserver reproducibility of LVFT/RR, IVMD and deltaS-peak [ICC= 0.99, 0.98 and 0.99, respectively], as well as the interobserver reproducibility [ICC: 0.96, 0.94 and 0.92, respectively], were very high. However, we observed a high variability for SPWMD measure [ICC=0.27, p=0.31]. Mechanical dyssynchrony did not correlate with QRS duration, despite the poor variability in collecting different echocardiographie parameters