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 longterm 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.