Prevalence of Mechanical Dyssynchrony in Patients With Heart Failure and Preserved Left Ventricular Function (a Report from the Belgian Multicenter Registry on Dyssynchrony)

The present study evaluated the prevalence of mechanical inter- and intraventricular dyssynchrony in patients with heart failure and preserved left ventricular (LV) ejection fraction (LVEF). We studied 138 patients with heart failure (age 67 ± 11 years; 76% men); 60 patients had preserved LVEF (>40%). Using conventional Doppler echocardiography, an interventricular mechanical delay ≥40 ms was defined as interventricular dyssynchrony. Using pulse-wave tissue Doppler imaging, the time from the beginning of the QRS complex to onset of systolic motion was measured in 4 basal LV segments. A dispersion of ≥60 ms was defined as intraventricular dyssynchrony. The prevalence of inter- and intraventricular dyssynchrony was lower in patients with preserved LVEF than in those with reduced LVEF (17% vs 41%, p <0.01 for interventricular dyssynchrony, 18% vs 36%, p <0.01 for intraventricular dyssynchrony). However, patients with preserved LVEF and a QRS width ≥120 ms had higher values for the parameters for inter- and intraventricular dyssynchrony than patients with a QRS width <120 ms (interventricular mechanical delay 33 ± 20 vs 20 ± 16 ms, p <0.05; tissue Doppler imaging dispersion 42 ± 26 vs 33 ± 22 ms, p <0.05). In patients with a QRS width ≥120 ms, the prevalence of inter- and intraventricular dyssynchrony was comparable for patients with preserved and reduced LVEF (42% vs 55%, p = NS for interventricular dyssynchrony and 45% vs 46%, p = NS for intraventricular dyssynchrony). In conclusion, the prevalence of inter- and intraventricular dyssynchrony was low (17% and 18%, respectively) in patients with heart failure and preserved LVEF. However, in the presence of a QRS width of ≥120 ms, this prevalence increased to almost 50%, comparable to that for patients with heart failure and reduced LVEF and a QRS width of ≥120 ms.