Assessment of Permanent Selective His Bundle Pacing in Left Ventricular Synchronization Using 3-D Speckle Tracking Echocardiography.

The study described here aimed to evaluate left ventricular (LV) systolic mechanical synchronization during permanent selective His bundle pacing (SHBP) using 3-D speckle-tracking echocardiography post-operatively and 6 mo after pacemaker implantation in 62 patients randomly assigned to SHBP (n = 32) or right ventricular apical pacing (RVAP, n = 30). A standard apex four-chamber view was exposed and was transformed into full-volume mode under 3-D echocardiography. Three-dimensional speckle-tracking echocardiography was analyzed offline. The primary endpoint was LV mechanical synchronization post-operatively and during the 6-mo follow-up. Significant LV dyssynchrony was detected while evaluating the maximum time difference and standard deviation of 16-segment systolic time to peak 3-D strain at 1 wk and 6 mo. The pacing thresholds were significantly higher in the SHBP than in the RVAP group throughout follow-up. The R-wave amplitude was significantly lower in the SHBP group than with RVAP. The pacing parameters during SHBP were as stable as during conventional RVAP during the mid-term follow-up. In conclusion, 3-D speckle-tracking echocardiography is feasible and provides a more convenient method for evaluating LV synchrony.