Iranian Red Crescent Medical Journal IRCMJ 2009; 11(2):193-198 ©Iranian Red Crescent Medical Journal SHORT COMMUNICATION Role of Tissue-Doppler Imaging to Assess Left Ventricular Function in Patients with Right Ventricular Pacing

Background: Right ventricular apical (RVA) pacing has been reported to impair diastolic and systolic function. These changes were usually studied by conventional echocardiography, while tissue-doppler imaging (TDI) has provided a new way to evaluate global and regional systolic left ventricular (LV) function and abnormal LV relaxa-tion. We designed this study to evaluate the changes of TDI-derived indices of asynchrony after RVA pacing. Methods: We followed 41 patients with LV ejection fraction (LVEF) 45 % and LV end-diastolic dimension (LVEDD) £ 56 mm who underwent single- or dual-chamber RVA pacemaker implantation for performing pace-maker analysis and second 2-dimensional (2D) echocardiography and TDI, at least 4.2 months later. 2D meas-urements included LVEDD, LV end-systolic dimension (LVESD), left atrial (LA) volume and septum to lateral asynchrony, while TDI measurements were the peak velocities of myocardial shortening (Sm) and early myocar-dial relaxation (Em). Results: Considering the exclusion criteria, 20 patients entered the study with the mean age of 66.05 years and follow-up of 7.86 months (4.20-12.25). The reduction of Sm, Em and LVEF, and the increment of LVEDD, LVESD, septum to lat asynchrony and LA volume were statistically significant. Changes of all these parameters, however, were independent of pacing duration, frequency or mode (single- or dual- chamber). Conclusions: RVA pacing has deleterious effects on both LV systolic and diastolic parameters of not only con-ventional echocardiography but also TDI even in patients with normal LV function. Furthermore, LA volume in-creases significantly