Clinical study endpoints
The primary endpoint of the study was to prospectively measure the CRT response rate at 6 months in subjects implanted with a QuartetTM LV quadripolar lead with the MPP feature activated compared to no CRT pacing at baseline. A positive CRT response was defined as a relative reduction in the left ventricle end-systolic volume (LVESV) of at least 15 % at 6 months post-implant, measured by echocardiography. Main secondary endpoints were reverse LV remodelling measured by changes in LV end diastolic volume and diameter (LVEDV and LVEDD) and by changes in LVESV and left ventricle end systolic diameter (LVESD); changes in NYHA class and in clinical composite score at 6 months; clinical outcomes at 6 months (mortality and all-cause hospitalization). Finally, a comparison of clinical outcomes with an historical control cohort corresponding to the patients involved in the previously conducted QUARTO II study12 was prespecified. The Quarto II study was a prospectively study that evaluated the usefulness of the quadripolar lead Quartet, the patterns of programming and the response to CRT in 198 patients implanted with a CRT-D device programmed into conventional single-site biventricular pacing. The Quarto II showed a percentage of responders of 62% (reduction ≥15% in LVEV) at 6 months of follow-up12.
All the echocardiography images were obtained by sites according to the study echo protocol at baseline and 6-month visit. They were submitted to the echo core lab for central evaluation and assessment. The echo core lab analysed and measured the echocardiographic images per the CIP and the echo protocol.