Additional value of three-dimensional echocardiography in patients with cardiac resynchronization therapy

There is no gold standard technique for quantification of ventricular dyssynchrony.

To investigate whether additional real-time three-dimensional morphologic assessment of ventricular dyssynchrony affects response after biventricular pacing.

Forty-one patients with severe heart failure were implanted with a biventricular pacing device and underwent two-dimensional (time dispersion of 12 left ventricular electromechanical delays) and three-dimensional echocardiographic assessment of ventricular dyssynchrony (dispersion of time to minimum regional volume for 16 left ventricular segments), before implantation, 2 days postimplantation with optimization of the pacing interventricular delay and 6 months postimplantation.

Individual optimization of sequential biventricular pacing based on three-dimensional ventricular dyssynchrony provided more improvement (p<0.05) in left ventricular ejection fraction and cardiac output than simultaneous biventricular pacing. During the different configurations of sequential biventricular pacing, the changes in three-dimensional ventricular dyssynchrony were highly correlated with those of cardiac output (r=-0.67, p<0.001) and ejection fraction (r=-0.68, p<0.001). The correlations between two-dimensional ventricular dyssynchrony and cardiac output or ejection fraction were significant but less (r=-0.60, p<0.01 and r=-0.56, p<0.05, respectively). After 6 months, 76% of patients were considered responders (10% decrease in end-systolic volume). Before implantation, we observed a significant difference between responders and non-responders in terms of three-dimensional (p<0.05) - but not two-dimensional - ventricular dyssynchrony.

This prospective study demonstrated the additional value of three-dimensional assessment of ventricular dyssynchrony in predicting response after biventricular pacing and optimizing the pacing configuration.