RESUMO
BACKGROUND AND OBJECTIVES: Numerous clinical studies have demonstrated chronic right ventricular (RV) pacing induced left ventricular (LV) dyssynchrony and LV systolic dysfunction in patients with permanent pacemaker. However, only a limited number of studies have focused on RV dysfunction. We sought to determine the prevalence and identify the clinical predictors of RV dysfunction in patients with chronic RV pacing. SUBJECTS AND METHODS: We enrolled 72 patients (mean age 72.7±11.1 years, men 36.1%) who underwent permanent pacemaker implantation without RV dysfunction in baseline examination. Baseline clinical characteristics, laboratory data, echocardiographic parameters and pacing profiles were assessed. Follow up 2-dimentional echocardiography was used to identify the presence of RV dysfunction. RESULTS: We divided patients based on the criteria of either presence or absence of RV dysfunction, where RV dysfunction is defined as decreased tricuspid annulus systolic velocity (<11 cm/sec) in tissue Doppler image. Sixteen patients (22.2%) in our study showed meaningful RV dysfunction. Patients with RV dysfunction had lower LV ejection fraction (57.5±10.8% versus 64.6±9.1%, p<0.05) and higher B-type natriuretic peptide (BNP) levels (700.3±152.9 pg/mL versus 329.4±332.4 pg/mL, p<0.05) compared to patients without RV dysfunction. Implantation of VVI type pacemaker was associated with presence of RV dysfunction (81.3% versus 33.3%, p<0.05). Higher cumulative ratio of total RV pacing was associated with increased tendency for RV dysfunction. No statistically significant correlation was observed between the groups (70.7±13.2% in RV dysfunction group, 61.7±38.3% in non-RV dysfunction group, p=0.094). CONCLUSION: In this study, meaningful proportion of patients showed chronic RV pacing induced RV dysfunction. RV dysfunction was associated with lower LV systolic function, higher BNP level and VVI type pacemaker.