Background: The aim of this study was to evaluate whether cumulative right ventricular apical pacing (RVAP) in patients with permanent pacemaker (PPM) implantation influence ventricular function and remodeling.
Methods: We performed echocardiography before and after PPM implantation to 87 patients (50 females, mean age: 68.3짹1.4 years, 51 sick sinus syndromes, 36 atrioventricular blocks, median follow-up duration: 26.2 months). Subjects were divided into infrequent (0-50%) pacing group and frequent (51-100%) pacing group with median pacing rate 1.0% and 99.7%, respectively. Echocardiographic parameters including the interventricular dyssynchrony (IVDS) were assessed to evaluate ventricular function and remodeling. IVDS was calculated as the difference between the pre-ejection intervals from the QRS onset to the beginning of ventricular ejection at the right and left ventricular outflow tract.
Results: LV ejection fraction (LVEF) was more decreased in frequent pacing group than in infrequent pacing group (-7.2짹5.6% vs.-2.52짹9.26%, p=0.017). The frequent pacing group showed significant IVDS prolongation than infrequent pacing group (23.8짹30.1 msec vs. 5.3짹16.5 msec, p=0.001). The changes of echocardiographic parameters of RV remodeling and function showed no significant differences between before and after PPM implantation in two groups (Table).
Conclusion: Frequent RVAP decreases LVEF but may not affect the RV function and remodeling, although IVDS significantly prolonged.
Key words: apical pacing, remodeling, ventricular function, dyssynchrony