Right ventricular apical and septal pacing: long term impacts on ventricular function

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): The costs of the study were afforded by the researchers. Background In patients requiring permanent pacemaker, in order to protect left and right ventricular functions the optimal pacing site has yet to be determined. Conflicting results exist about septal and apical pacing sites. Aim Our purpose was to evaluate the long term effects of right ventricular apical and septal pacing on left and right ventricular functions. Methods We scanned 378 patients from 2007 to 2012 who received a permanent pacemaker for the treatment of symptomatic bradyarrythmia. As exclusion criteria we identified the patients who did not have an echocardiography before the procedure, those who had co-morbidities which cause reduction in ventricular functions, ejection fraction <%45, patients who died and those who rejected our invitation. 54 women and 66 men were eligible for our study. To determine the patients’ New York Heart Association Class (NYHA) we questioned and did the physical examination. Lead position confirmed by fluoroscopy in two planes, and electrocardiograms were obtained. Finally, we compared the pre-procedural echocardiographic data with our up-to-date findings. Results In sixteen patients the lead placement was inferoseptal and in one hundred and four patients apical site. Median follow up was 9 years. The mean ejection fraction before the implantation was 58,86 ± 4,08 in the apical, and 56,37 ± 8,8 in the septal group (p < 0,05). The long term follow up showed that these values have been reduced, 56,66 ± 8,38 for the apical group and 51,33 ± 13,94 for the septal group, respectively (p < 0,05). Placing the right ventricular lead in both septal and apical site resulted in reduced tricuspid annular plane systolic excursion (from mean 2,25 to 2,18, (p < 0,05)), and in increased systolic pulmonary artery pressure (from 35,46 ± 9,93 to 39,84 ± 11,21 (p < 0,05)). There were no differences regarding the mitral and tricuspid insufficiencies, and diastolic functions before the implantation and long term follow up. These findings were independent of neither the etiology of implanting the pacemaker nor the underlying diseases. Conclusion These two selective ventricular pacing sites caused a reduction in both left and right ventricular functions. Despite the ejection fraction declines, most of these patients have a good quality of life, without symptoms and signs of heart failure. But certainly, there is emerging need for more randomized trials in order to describe the optimal RV pacing site. The main purpose must be preserving better ventricular functions in patients requiring permanent ventricular pacing.