Background Right ventricular (RV) artificial apical pacing can negatively impact synchrony of
left ventricular contraction. The pacing from the septum of the RV can present an advantage
in terms of less expressed dyssynchrony and reduced negative impact on left ventricular (LV)
function. However, results of randomized studies comparing apical and septal pacing are not
uniform. All these results have been affected by improper implantation of the septal lead,
with many apparently septal leads being, in fact, implanted off-septum. The aim of the study
is to compare true septal pacing with other RV pacing locations.
Methods/Design This is a prospective, randomized, single center study. Patients with standard
indications for cardiac pacing with the expectation of high percentage RV pacing will be
enrolled. They will be randomized into apical and septal pacing. The real location of leads
in patients randomized to septal pacing will be confirmed using cardiac CT. After cardiac CT,
three groups of patients will be created: 1) apical pacing, 2) true septal (in which the
position of the lead has been verified to be in the septum), and 3) apparent septal (in which
the position of the lead was found to be off-septum). Primary end-point are changes in
standard echocardiographic parameters (LV ejection fraction, LV end-systolic volume, and LV
end-diastolic volume) and the concentration of N-terminal pro brain natriuretic peptide
(NT-proBNP) from baseline to 6 months, 1 year and three years. Secondary end-points are
changes in echo-parameters of LV synchrony.
Discussion It is hypothesized that correct septal pacing will be associated with reduce
negative impact on the function of the left ventricle (i.e. smaller decreases in LV EF and
smaller increases in LVEDV, LVESV) and NT-proBNP, and less expressed LV dyssynchrony.