Unfavourable effects of continuous, atrial-synchronised ventricular pacing on ventricular systolic and diastolic function in patients with normal left ventricular ejection fraction: usefulness of tissue and colour Doppler echocardiography.

INTRODUCTION Conventional, atrial-synchronised, right ventricular apical pacing (VP) may compromise ventricular function by causing ventricular desynchronisation. The aim of this study was to evaluate the long-term effects of VP on left and right ventricular systolic and diastolic function. METHODS We studied 21 clinically stable dual-chamber pacemaker recipients (mean age 68 +/- 9 years) with normal left ventricular (LV) systolic function. Patients were in long-term sinus rhythm and had intrinsic ventricular activation with narrow QRS complexes. In an intrapatient model, baseline echocardiographic and tissue Doppler imaging (TDI), colour M-Mode (CMM) examinations, as well as plasma B-type natriuretic peptide (BNP) data, were compared to corresponding measurements following a 3-month period of continuous VP. RESULTS Following VP we noted significant increases in LV end-systolic volume (p < 0.001) and isovolumic relaxation time (p < 0.05), as well as a significant decline in LV systolic function based on ejection fraction (p < 0.001) and TDI-Sa (p < 0.05). VP was associated with worse LV diastolic function, based on CMM-Vp (p < 0.05) and increased E/Vp ratio (p < 0.05), but with similar E/Ea ratio and BNP levels (p: NS). CONCLUSIONS VP appears to impair LV systolic and diastolic function and may predispose to higher LV filling pressures.