Key result
In a canine model of induced atrial fibrillation, CRT with coupled pacing increased left ventricular systolic pressure (136 vs 86 mmHg, P<0.05) and cardiac output compared with CRT alone.
Why the study?
Does CRT with coupled pacing improve left ventricular function in a canine model of atrial fibrillation?
Does CRT with coupled pacing improve left ventricular function in a canine model of atrial fibrillation?
In a canine model of AF, CRT combined with coupled pacing improved systolic and diastolic performance without inducing mechanical dyssynchrony compared to CRT alone or CRT with vagal stimulation.
AIMS: Electrical stimulation [coupled pacing (CP)] applied near the end of the T-wave is able to create a retrograde activation of the atrioventricular (AV) node in turn to prevent rapid ventricular conduction during atrial fibrillation (AF). The impact of this pacing modality associated with cardiac resynchronization therapy (CRT) has been evaluated in the present experimental study. METHODS AND RESULTS: After inducing AF by rapid pacing in six dogs, we applied the following pacing modalities: rapid right ventricular (RV) pacing, rapid CRT, CRT with an additional RV paced beat (CP) at a specific delay (CRT + CP), and CRT with vagal stimulation (CRT-VS). Left ventricular (LV) pressure recordings and echocardiography for 2D strain analysis were performed. CRT + CP reduced the ventricular response rate and increased the LV systolic pressure and cardiac output compared with CRT alone (136 +/- 6 vs. 86 +/- 13 mmHg, P < 0.05 and 2.0 +/- 0.4 vs.1.2 +/- 0.1, P < 0.05 L/m, respectively). Compared with CRT-VS, CRT + CP increased the LV ejection fraction (LVEF = 51 +/- 10 vs. 28 +/- 4%, P < 0.05), peak global circumferential strain (-17 +/- 2 vs. -11 +/- 3%), and diastolic filling time (49 +/- 6 vs. 28 +/- 3%, P < 0.02) suggesting beneficial effects of CP beyond rate control. CRT + CP did not result in increased dyssynchrony [CRT (8.3 +/- 2%) vs. CRTCP (8.4 +/- 3%, P = NS)]. CONCLUSION: CRT + CP effectively reduces ventricular contractile rate and leads to an increase in systolic and diastolic performance without inducing mechanical dyssynchrony.
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Lim et al. (2010) studied Atrial fibrillation (n=6). Cardiac resynchronization therapy with coupled pacing (CRT + CP) vs. CRT alone and CRT with vagal stimulation was evaluated on Left ventricular systolic pressure (mmHg) (p=<0.05). In a canine model of induced atrial fibrillation, CRT with coupled pacing increased left ventricular systolic pressure (136 vs 86 mmHg, P<0.05) and cardiac output compared with CRT alone.
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