2. Non-apical RV pacing
RV septal pacing is the only one during the last decade for which randomized studies have been conducted both for indications of high-grade atrioventricular (AV) block disorders and cardiac resynchronization therapy. Regarding the first indication, the Protect-Pace study compared RV apical and septal pacing.3 There were randomized 240 patients with preserved Left Ventricular Ejection Fraction (LVEF) > 50%, requiring high-burden RV pacing > 90%, for two years of follow-up. The study concluded that LVEF decreased in both groups (apical and septal) to the same non-statistically significant degree. At the same time, there was no significant difference in heart failure hospitalizations, mortality and atrial fibrillation burden as well as biomarkers levels, such as Brain Natriuretic Peptide (BNP). On the contrary, a longer time was required for the RV septal implantation procedure with an increase up to doubling the fluoroscopy time.
Regarding RV septal pacing compared to RVA for the application of cardiac resynchronization therapy (CRT), the randomized study performed was the SEPTAL CRT study.4 263 patients were randomized for septal and apical pacing in the CRT context. The results showed non-inferiority of septal, compared to the apical position of the RV electrode, in terms of reduction of echocardiographically determined left ventricular end-systolic volume (LVESV) and composite clinical endpoint of deaths and hospitalizations for heart failure, at a 6-month follow-up. The above two studies were the cause that RV septal pacing did not officially approve for routine implementation in permanent pacemaker implantations.
The precise placement of the RV electrode in a septal position is a matter that is not easy to ascertain through the fluoroscopy currently used. Nevertheless, in addition to the above two randomized studies, a meta-analysis of all available studies demonstrated a benefit of non-apical RV pacing, compared to apical, in patients who had pre-implantation reduced LVEF <40%.5Furthermore, in an observational study, in 2200 patients having 3822 active-fixation pacing and defibrillation leads, the apical location of the RV lead, especially for female gender and age >80 years, appeared to be statistically associated with cardiac perforation.6 Therefore, the effort to place the electrode in a non-apical position with the data so far is not systematically recommended for every patient needing pacing therapy but should perhaps be considered for these specific categories. The summarized data for non-apical RV pacing instead of RV apical pacing is in Table 1 .