Comparison of effectiveness of right ventricular mid-septal pacing vs. apical pacing: a randomized-controlled trials

The aim of the present study was to compare conventional right ventricular apical pacing (RVAP) with right ventricular mid-septal pacing (RVMSP) in terms of echocardiographic and clinical/biologic features. Ninety-six patients with high-degree atrioventricular block were randomly allocated to RVMSP (n = 50) and RVAP (n = 46). Threshold and impedance, echocardiographic left ventricular ejection fraction, ventricular dyssynchrony features, and distance during a 6-min walk test and Minnesota Living with Heart Failure Questionnaire were determined at 6 and 12 months after pacemaker implantation. Serum levels of N-terminal pro-brain natriuretic peptide were measured. At 6 months of follow-up, echocardiographic and clinical/biologic features showed no significant differences between two groups. The RVAP group had more intraventricular dyssynchrony and a trend towards a worse left ventricular ejection fraction compared with the RVMSP at 12 months of follow-up. However, no overt clinical benefits from RVMSP were found. Right ventricular mid-septal pacing was associated with decreased dyssynchrony and better left ventricular ejection fraction compared with the RVAP. Right ventricular mid-septal pacing could represent an alternative pacing site in selected patients to reduce the harmful effects of traditional RVAP.