Mechanical dyssynchrony by 3D echo correlates with acute haemodynamic response to biventricular pacing in heart failure patients

Aims One-third of dilated cardiomyopathy patients receiving a biventricular pacing-device do not respond to this form of therapy. Therefore, the utility of mechanical dyssynchrony by real-time 3D echo-cardiography (RT3DE) for predicting systolic response to biventricular pacing, of which maximal rate of pressure rise (dP/dt(max)) served as the gold-standard, was evaluated. Methods and results Seventeen consecutive heart failure patients (aged 64 +/- 10 years, 8 male, 6 ischaemic cardiomyopathy, mean QRS duration 136 +/- 32 ms) underwent RT3DE and biventricular pacing. Post-processing software provided data of global left ventricular (LV) function and the systolic dyssynchrony index of 17 LV segments (SDI(17), %) for mechanical dyssynchrony. During biventricular pacing, percentual change in dP/dt(max) compared to the non-pacing mode, Delta dp/dt(max) was measured invasively with conductance catheters. LV ejection fraction was 31 +/- 10%, SDI(17) was 10.2 +/- 4.2% and percentual Delta dP/dt(max) during biventricular pacing was 14.5 +/- 12.4. A significant correlation (r = 0.729, P = 0.001) was found between SDI17 and percentual Delta dP/dt(max), and between QRS duration and percentual Delta dP/dt(max) (r = 0.721, P = 0.001). Conclusion The present study suggests that mechanical dyssynchrony measured by RT3DE shows a good correlation with invasivety determined acute haemodynamic response to biventricutar pacing in patients with symptomatic dilated cardiomyopathy. Future studies are needed to further define the clinical utility of RT3DE in identifying patients who are most likely to respond to cardiac resynchronization therapy.