Introduction
Cardiac resynchronization therapy (CRT) provides significant long-term
benefits to patients with moderate to severe heart failure (HF),
prolonged QRS duration, and reduced ejection fraction
(EF).1–3 However, up to 40% of patients fail to
clinically respond to conventional CRT.4,5 Multipoint
left ventricular (LV) pacing (MultiPoint™ Pacing [MPP], Abbott,
Sylmar, CA), stimulating two LV sites on a quadripolar lead, is one key
strategy to improve CRT response over conventional biventricular (BiV)
pacing.
Head-to-head comparisons have demonstrated improvements of MPP over BiV
in terms of LV pressure response6–9, LV peak radial
strain10, LV electrical
activation11, and long-term LV
function12–15. The benefits of the additional LV
pacing vector, however, come with the burden of additional programming
options. In MPP clinical studies to date, selection of the two LV pacing
vectors (each with up to 14 LV cathode-anode combinations) has either
(1) been guided by manual, in-clinic electrical or hemodynamic
measurements, or (2) left entirely to the discretion of the physician.
Consequently, any clinical improvement ultimately observed cannot be
directly associated with a single, consistent programming guideline that
can be implemented routinely in-clinic. The current study is the first
randomized comparison of MPP and BiV in the Middle East that relied
solely on one automated, programmer-based tool
(VectSelectTM, Abbott) which provides MPP LV pacing
vector recommendations that are both patient-specific and require
minimal physician input.
In this prospective, multi-center investigation, patients were implanted
with CRT-D devices and randomized to receive either BiV pacing or MPP.
Patient response to CRT was quantified after 6 months by reductions in
LV end-systolic volume (ESV) and elevations in LV ejection fraction
(EF), both indicative of a reversal of the LV dilation and dysfunction
associated with heart failure (i.e., LV reverse remodeling).