Effect of right ventricular pacing on cardiac function and exercise capacity in patients with chronic heart failure

ZHOU Qing-hua; D.G.Gibson

doi:10.3760/cma.j.issn.1673-4777.2011.05.001

Abstract：Objective To investigate the effect of optimal atri-ventrieular(AV)delay right ventricular pacing on cardiac function and cardiopulmonary exercise function.Methods Thirty-one chronic heart failure patients with dilated cardiomyopathy and conduction delay.All who were implanted DDD pacemaker were studied by M-mode and Doppler echocardiogram during VDD mode at optimized AV delay.Peak VO2,AT and VE/VCO2 were assessed by cardiopulmonary exercise test.Results After pacing,QRS duration did not have significant changes(P>0.05).Left ventricular dimension and left atrial dimension did not significantly change.Left free wall long axis excursion were similar[(0.8 4±0.4)cm vs(0.9 ±0.4)cm].Septal wall long axis motion did not have significant changes [(0.5 ±0.3)cm vs(0.4 ±0.3)cm].Left ventricular ejection time and stroke distance were similar.23%(7/31)patients MR disappeared.77%(24/31)patients'duration of mitral regurgitation reduced[(408±9)ms vs(486 ±101)ms]and ratio of duration of mitral regurgitation to RR interval were reduced[(74±10)%vs(57±17)%,all P<0.05].Positive peak dp/dt were increased[(702±147)mm Hg/s vs(532±213)mm Hg/s,P<0.01].Peak VO2 and exercise duration were increased than baseline.AT and VE/VCO2 slope did not show any significant difference.Conclusions Right ventricular pacing with optimal AV delay in patients with chronic heart failure,together with programming of AV delay at rest,can reduce mitral rcgnrgitation,increase left ventricular contractility and left ventricular diastolic filling time as well as improve left ventricular performance index.Peak VO2 and exercise time can be improved in these patients.However AT and ventilatory efficiency cannot be improved significantly.