Absence of additional improvement in outcome of patients receiving cardiac resynchronization therapy paced at the most delayed left ventricular region

SummaryBackgroundThe choice of the optimal left ventricular (LV) pacing site remains an issue in patients requiring cardiac resynchronization therapy (CRT).AimThis prospective study compared the outcome of patients paced at the most delayed LV region with that of patients paced at any other LV site.MethodsForty-four patients with severe heart failure underwent three-dimensional (3D) echocardiography before implantation and 3 days after implantation of a CRT device, to determine the most delayed LV region during spontaneous rhythm and during right ventricular pacing. The patients were divided subsequently into four groups: group 1 (n=19), LV lead placed at the most delayed echocardiographic site in spontaneous rhythm; group 2 (n=25), LV lead placed at any other site; group 3 (n=21), LV lead placed at the most delayed echocardiographic site during right ventricular pacing; group 4 (n=23), LV lead placed at any other site.ResultsNo significant differences were observed between the four groups before implantation. After 6 months of CRT, no significant differences were observed between groups 1 and 2 or between groups 3 and 4 in terms of change in New York Heart Association functional class, Minnesota living with heart failure questionnaire, 6-minute walk test, peak exercise oxygen consumption, 3D ventricular dyssynchrony and 3D LV ejection fraction.ConclusionImplantation of the LV lead in the most delayed region of the left ventricle determined by 3D echocardiography did not result in additional improvement in symptoms or LV function