B-po04-183 adaptive cardiac resynchronization therapy effect on electrical dyssynchrony-a randomized controlled trial

Multiple studies reported clinical benefits of adaptive cardiac resynchronization therapy (aCRT) over conventional CRT; however, their effect on electrical dyssynchrony was not studied. The objective of this study was to compare the effects of aCRT and conventional CRT on electrical dyssynchrony. In this trial we randomized 27 patients (mean age 64±12 y; 34% female; 53% ischemic cardiomyopathy; left ventricular ejection fraction 28±8%; QRS duration 155±21 ms; 56% left bundle branch block (LBBB) of which 15% met strict LBBB criteria) to conventional CRT (n=15) versus aCRT (n=12). Electro-anatomical data were collected through cardiac computed tomography and 128-electrodes body surface mapping (figure). Electrical dyssynchrony on the epicardial surface was calculated using noninvasive electrocardiographic imaging (ECGI) before and 6 months post-CRT. Ventricular electrical uncoupling (VEU) was calculated as the difference between the mean LV and RV activation times. Electrical dyssynchrony index (EDI) was calculated as the standard deviation of local epicardial activation times. In atypical LBBB (n=11;41%), conduction block occurred in the anterior RV, whereas in strict LBBB (n=4;15%), it was observed near the interventricular groove (figure). As compared to baseline, VEU decreased post-CRT in aCRT (median reduction 18.9 (interquartile range 4.3-29.2 ms; P=0.034), but not in conventional CRT (21.4 (-30.0 to 49.9 ms; P=0.525) group. No differences in the degree of change in VEU and EDI indices were found between the treatment groups. The effect of aCRT and conventional CRT on electrical dyssynchrony is largely similar.