Right Ventricular Apical Versus True Mid-septal Pacing

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.