AIMS: Long-standing right ventricular apical pacing (RVAP) may result in impaired left ventricular (LV) function and systolic heart failure (HF) in selected patients. However, which patients are susceptible to those harmful effects is unknown. METHODS AND RESULTS: In 367 consecutive patients undergoing pacemaker implantations (PMIs) and RVAP, the clinical, laboratory, and echocardiographic data before the PMIs, electrocardiographic parameters [baseline and paced QRS duration (QRSd)], and echocardiography were analysed. The cumulative per cent of those ventricularly paced (Cum%VP) was >90% in all subjects. During a mean follow-up period of 113±69 months, the occurrence of HF requiring hospitalization for the intravenous administration of HF medications was found in 60 patients (16%; HF group), but not in the remaining 307 (84%; no-HF group). The prevalence of structural heart disease (SHD; P<0.0001), cardiothoracic ratio (P<0.0001), baseline left atrial size (P=0.0001), LV end-diastolic volume (P<0.005) and end-systolic volume (P<0.0005), LV mass index (P<0.001), and baseline and paced QRSd (both for P<0.001) were greater in the HF group than in the no-HF group. Inversely, the LV ejection fraction (LVEF) in the HF group was smaller than that in the no-HF group (P<0.001). The multivariate Cox regression analysis revealed that the presence of SHD [hazard ratio (HR)=3.12; 95% confidence interval (CI), 1.7-5.7; P<0.001] and the LVEF (<40%; HR=2.57; 95% CI, 1.09-6.07; P<0.05) were associated with hospitalizations due to HF after RVAP. CONCLUSION: The presence of SHD and an impaired LV systolic function before the PMI may predict hospitalizations due to HF after RVAP.
AIMS: Long-standing right ventricular apical pacing (RVAP) may result in impaired left ventricular (LV) function and systolic heart failure (HF) in selected patients. However, which patients are susceptible to those harmful effects is unknown. METHODS AND RESULTS: In 367 consecutive patients undergoing pacemaker implantations (PMIs) and RVAP, the clinical, laboratory, and echocardiographic data before the PMIs, electrocardiographic parameters [baseline and paced QRS duration (QRSd)], and echocardiography were analysed. The cumulative per cent of those ventricularly paced (Cum%VP) was >90% in all subjects. During a mean follow-up period of 113±69 months, the occurrence of HF requiring hospitalization for the intravenous administration of HF medications was found in 60 patients (16%; HF group), but not in the remaining 307 (84%; no-HF group). The prevalence of structural heart disease (SHD; P<0.0001), cardiothoracic ratio (P<0.0001), baseline left atrial size (P=0.0001), LV end-diastolic volume (P<0.005) and end-systolic volume (P<0.0005), LV mass index (P<0.001), and baseline and paced QRSd (both for P<0.001) were greater in the HF group than in the no-HF group. Inversely, the LV ejection fraction (LVEF) in the HF group was smaller than that in the no-HF group (P<0.001). The multivariate Cox regression analysis revealed that the presence of SHD [hazard ratio (HR)=3.12; 95% confidence interval (CI), 1.7-5.7; P<0.001] and the LVEF (<40%; HR=2.57; 95% CI, 1.09-6.07; P<0.05) were associated with hospitalizations due to HF after RVAP. CONCLUSION: The presence of SHD and an impaired LV systolic function before the PMI may predict hospitalizations due to HF after RVAP.