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.