Epicardial biventricular pacing improved left ventricular systolic mechanics compared with right ventricular apex pacing (12.8 vs 8.3 mmHg/mL, P<0.02) in an immature piglet model of AV block.
Does epicardial biventricular or left ventricular apex pacing improve myocardial performance compared to right ventricular apex pacing in an immature animal model of AV block?
In an acute immature piglet model of AV block, biventricular and left ventricular apical pacing improved left ventricular performance and mechanical synchrony compared to right ventricular apical pacing.
Absolute Event Rate: 12.8% vs 8.3%
p-value: p=<0.02
INTRODUCTION: Single-site ventricular pacing results in dyssynchronous ventricular activation and may contribute to ventricular dysfunction. We evaluated epicardial biventricular (BiV) pacing as a means of maintaining synchronous ventricular activation in an acute piglet model of AV block with normal ventricular anatomy and function. METHODS AND RESULTS: We used left ventricular (LV) impedance catheters and tissue Doppler imaging to assess the cardiodynamics of immature piglets (n = 6, 33-78 days, 9.35 +/- 0.85 kg). Following catheter ablation of the AV node, a pacemaker was programmed 20 beats per minute above the intrinsic atrial rate. The animals were paced at 5-minute intervals via the following AV sequential configurations: Right atrial appendage (RA)-RV apex (RVA), RA-LV apex (LVA), and RA-biventricular (RVA/LVA). RA-RVA was the experimental control. LV systolic mechanics, measured by the slope of the end-systolic pressure-volume relationship (E(es)), increased with BiV pacing (12.8 +/- 3.4 mmHg/mL, P < 0.02) or single-site LVA pacing (10.6 +/- 3.4 mmHg/mL, P < 0.05) compared with single-site RVA pacing (8.3 +/- 1.4 mmHg/mL). QRS duration lengthened compared with sinus rhythm (42 +/- 8 msec) with either RVA (56 +/- 9 msec, P < 0.02) or LVA (54 +/- 7 msec, P < 0.03), but not with BiV (48 +/- 7 msec, P = 0.08) pacing. Tissue Doppler imaging showed LV dyssynchrony with RVA (septal-to-lateral delay 46.0 +/- 51.7 msec), with return toward normal with LVA (-9.6 +/- 33.6 msec, P < 0.04) or BiV (-4.1 +/- 33.8 msec, P < 0.04) pacing. CONCLUSIONS: In this acute immature piglet model of AV block, LV performance improved with single-site pacing from the LVA and BiV pacing (RVA/LVA), as compared with single-site pacing from the RVA. These changes correlated with tissue Doppler indices of mechanical synchrony, though not necessarily with QRS duration.
Cojoc et al. (Tue,) conducted a other in Atrioventricular block (n=6). Epicardial biventricular (BiV) pacing vs. Single-site right ventricular apex (RVA) pacing was evaluated on Left ventricular systolic mechanics (slope of the end-systolic pressure-volume relationship, E(es)) (p=<0.02). Epicardial biventricular pacing improved left ventricular systolic mechanics compared with right ventricular apex pacing (12.8 vs 8.3 mmHg/mL, P<0.02) in an immature piglet model of AV block.