Study on the effects of different pacing modes of cardiac resynchronization therapy on dogs with heart failure / 中国医师杂志

ABSTRACT

Objective To evaluate advantages and disadvantages of different pacing modes of cardiac resynchronization therapy (CRT).Methods Twelve dogs with heart failure were performed in every dog at random,and the pacing modes employed in the test included right atrium-different sites of ventricle,and ventricular sites included right ventricular bifocal (RV-Bi),biventricular (Bi-V),left ventricular (LV).The pacing frequency was 180 times per minute,and the results were measured before pacing and after 15 minutes when the pacing became stable in Color Doppler echocardiography,including left ventricular enddiastolic diameter (LVEDd),left ventricular ejection fraction (LVEF),interventricular mechanical delay (IVMD),interventricular septum and left ventricular posterior wall motion delay (SPWMD),left ventricular 12-segment peak time standard deviation (Ts-SD).Results (1)Compared with before pacing,at the RV-Bi,Bi-V,and LV pacing modes,LVEDd,IVMD,SPWMD,and Ts-SD decreased,LVEF increased,the difference was statistically significant [(42.42 ± 3.94) mm vs (34.00 ± 4.07) mm,(34.17 ± 3.95)mm,(33.75 ±4.18)mm; (28.08 ±4.01)mm vs (13.00 ±3.64) mm,(11.95 ±2.54)mm,(12.08 ±3.51) mm; (75.00 ± 10.22)mm vs (51.75 ±9.84) mm,(20.66 ±7.41) mm,(20.75 ±7.56) mm; (25.08±4.16)mm vs (14.91 ± 3.31)mm,(7.50 ±4.24) mm,(7.41 ±3.39)mm;(32.91 ±4.46)mm vs (41.50 ±4.16)mm,(42.00 ±4.63) mm,(42.41 ±4.99)mm,P ＜0.05].(2)Compared with RV-Bi pacing mode,at the Bi-V,LV pacing modes,SPWMD and Ts-SD decreased,the difference was statistically significant(P ＜ 0.05); there was no significant difference among LVEDd,IVMD,and LVEF (P ＞0.05).(3)There was no significant difference in LVEDd,IVMD,SPWMD,Ts-SD and LVEF between LV and Bi-V pacing (P ＞ 0.05).Conclusions The hemodynamic effects of RV-Bi and LV pacing modes were similar to that of Bi-V pacing,and they can be used as CRT biventricular pacing alternative modes; however,the mechanisms of improving ventricular synchronization are not identical in above pacing modes.