Permanent and Atrial-Synchronized Ventricular Stimulation for Clinically Stable Patients with Normal or Impaired Left Ventricular Systolic Function JOHN A. CHILADAKIS, M.D., F.E.S.C., NIKOLAOS KOUTSOGIANNIS, M.D., ANDREAS KALOGEROPOULOS, M.D., FANI ZAGLI, M.D., ILIAS SIHLIMIRIS, M.D., and DIMITRIOS ALEXOPOULOS, M.D., F.A.C.C., F.E.S.C. From the Department of Cardiology, Patras University Hospital, 26500 Rion, Patras, Greece Background: Ventricular desynchronization imposed by permanent dual-chamber ventricular pacing (VDD) may compromise ventricular function. Methods: We investigated the impact of background VDD pacing on the right and left ventricular (LV) function on 129 clinically stable outpatients (mean age 69 ± 10) implanted chronically with a dual- chamber pacemaker or an automatic defibrillator by using echocardiographic techniques including tissue doppler imaging (TDI) and color M-mode (CMM) examinations, and B-type natriuretic peptide (BNP) measurements. Patients were divided into two groups of normal (n = 65) or impaired (n = 64) LV systolic function (ejection fraction 63 ± 6% and 38 ± 10%, respectively) according to clinical and echocardio- graphic criteria. Each patient group included two subgroups on the basis of the underlying permanent and atrial-synchronized heart rhythm: either intrinsic ventricular activation (IVA) or VDD pacing. Results: The BNP levels (mean, 95% CI) of patients with impaired LV systolic function were approxi- mately threefold higher than those of patients with normal LV systolic function [189 (145–245) pg/mL vs 65 (50–85) pg/mL, P < 0.0001], but did not differ between subgroups of patients with IVA vs VDD pacing. By two-way analysis of variance and analysis of covariance, and after adjustment for age and gender, signif- icant VDD pacing effects were found in terms of lower E/A ratio (P < 0.05) and increased LV end-systolic volume (P < 0.05). VDD pacing did not significantly affect the BNP levels and the LV filling pressures, as determined by the E/Ea and E/Vp ratios. Conclusions: Long-term VDD pacing may not be harmful in clinically stable patients with normal or moderately reduced LV systolic function. (PACE 2007; 30:182–187) permanent VDD pacing, ventricular function Introduction Dual-chamber devices are often preferred in patients with atrioventricular (AV) block and in patients with impaired left ventricular (LV) ejec- tion fraction. Recently, concerns have been revived about the potential deleterious effects of the ab- normal excitation on the ventricular myocardium imposed by right ventricular (RV) pacing, despite maintenance of AV synchrony, particularly in pa- tients with impaired LV systolic function. 1–5 How- ever, if one considers the results from other stud- ies in patients with normal LV systolic function, it could be assumed that atrial-based ventricular pacing may not be unequivocally harmful. 6,7 Con- ceivably, much remains to be clarified about the mechanisms which might be related to the possi- ble detrimental effects of AV sequential pacing 8–11 with standard right ventricular apical stimulation. Address for reprints: John A. Chiladakis, M.D., F.E.S.C., Asst. Professor of Cardiology, Tavropou 16, Patras 26442, Greece. Fax: +30-2610-430-646; e-mail: chil@otenet.gr Received August 9, 2006; revised October 4, 2006; accepted October 11, 2006. In this study, we used Doppler echocardiogra- phy with the newer indexes of left and right sys- tolic and diastolic function measured from color M-mode (CMM) and tissue Doppler imaging (TDI), and the plasma B-type natriuretic peptide (BNP) levels, which have been proven useful tools to evaluate cardiac function. We aimed to investigate the impact of background permanent atrial syn- chronous ventricular (VDD) pacing on the right and the LV systolic and diastolic function of clini- cally stable patients with dual-chamber devices. Methods Study Patients We studied 129 patients implanted for at least 6 months with a common market-released dual- chamber pacemaker or an automatic cardioverter defibrillator using standard techniques. All ven- tricular leads had been positioned in the right ven- tricular apex. All patients were in sinus rhythm, maintained AV synchrony, and were included in the study if they had on long-term the same cardiac rhythm, either normal intrinsic ventricular activa- tion (IVA) with narrow QRS complexes <120 ms and PR interval <240 ms, or continuously VDD C 2007, The Authors. Journal compilation C 2006, Blackwell Publishing, Inc. 182 February 2007 PACE, Vol. 30