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 .