Echocardiographic assessment of left ventricular dyssynchrony and correlation with QRS width in chronic heart failure.
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) > or = 40 milliseconds, all of them had a QRS duration > or = 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 > or = 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 echocardiographic parameters.