QUARTO III. Response rate in cardiac resynchronization therapy patients
implanted with a left ventricular quadripolar lead and the MultiPoint TM
Pacing feature activated.
Abstract
BACKGROUND: Although cardiac resynchronization therapy (CRT) is
beneficial in most heart failure patients, up to 40% do not respond to
CRT. It has been suggested that multipoint left ventricle pacing (MPP)
would increase the response rate. AIM: To assess the CRT
response rate at 6 months in patients implanted with a CRT device with
the MPP feature activated early after the implant. METHODS This
was a multicentre, prospective, open-label and non-randomized study. The
primary endpoint was response to biventricular pacing defined as
>15% relative reduction in left ventricular end-systolic
volume (LVESV) comparing echocardiography measurements performed at
baseline and 6 months by a core laboratory. Among secondary endpoints
the combined endpoint of mortality or all-cause hospitalizations was
evaluated. Primary study endpoint and clinical outcomes were compared to
a Quarto II control cohort. RESULTS: 105 patients were
included. The response rate was 64.6% (97.5% lower confidence bound
53%). Mean relative reduction in LVESV was 25.3% and mean absolute
increase in LVEF was 9.4%. The subjects with device programmed using
anatomical approach had showed a trend toward higher responder rate than
those using the electrical approach (72% vs. 61.1%, p= 0.32). Compared
with Quarto II, the combined endpoint of mortality and or all-cause
hospitalizations was lower in Quarto III (12.4% vs 25.4%, p=0.004).
CONCLUSIONS: Early activation of MPP was not associated to an
advantage increasing echocardiography responders to CRT at 6 months of
follow up. Nevertheless, MPP was associated with better clinical
outcomes in comparison to a historical control cohort. Patients
programmed using widest pacing cathodes had a numerically higher
responder rate.