Methods: In 41 consecutive patients (87.8% male; mean age 66.0 ± 12.7 years) who received CRT defibrillators with a quadripolar LV lead, RT3DE datasets were acquired the day after implantation under the following pacing configurations: Baseline AAI, conventional biventricular pacing using distal or proximal LV poles and MPP. Datasets were analyzed in paired samples evaluating SDI and LVEF depending on programmed pacing modality.
Results: MPP resulted in statistically significant reduction of SDI compared to baseline (6.3%; IQR 4.4-7.8 and 9.9%; IQR 8.0-12.7; p<0.001) and to conventional biventricular pacing using distal (7.6%; IQR 6.5-9.1; p<0.001) or proximal (7.4%; IQR 6.2-8.8; p<0.001) LV poles respectively. MPP yielded significant increase in LVEF compared to baseline (30.6%; IQR 25.8-37.5 and 27.2%; IQR 21.1-33.6; p<0.001) and to conventional biventricular pacing configuration with distal (28.1%; IQR 22.1-34.5; p<0.001) or proximal (28.6%; IQR 23.2-34.9; p<0.001) LV poles respectively.
Conclusion: Multipole pacing improves mechanical dyssynchrony of the left ventricular myocardium as assessed by SDI and LVEF.