J. Claude Daubert, Christine Alonso, Philippe Mabo, Christophe Leclerq.
Département de Cardiologie et Maladies Vasculaires, Centre Cardio-Pneumologique, Hôpital Pontchaillou - CHU, Rennes, France
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Despite pharmacological advances, the introduction of ACE
inhibitors and beta-blockers in particular, the prognosis of patients with severe heart failure (grades
III and IV of the NYHA classification) remains pejorative and their quality of life is poor. A number of
non-pharmacological treatments have been proposed for this type of patients: heart transplantation
remains the reference treatment although its application is restricted by donor shortage, among
other factors. Left ventricular support devices are still at the evaluation stage and the results of
cardiomyoplasty are highly controversial. In the early 90s, standard dual-chamber pacing with short
AV delay was proposed as a supplementary treatment of drug-resistant heart failure1-4. Initial
results were encouraging but were never confirmed. These studies however made it possible to
select a population of potentially responsive patients, especially those with a prolonged PR interval
reflecting major atrioventricular asynchrony in the left heart5. That relative failure of standard
dual-chamber pacing could be linked to the fact that by capturing the ventricle from the right apex, it
increases, or at least it cannot correct the marked asynchrony of activation, contraction and relaxation
which characterizes a number of patients with chronic left ventricular dysfunction. Such is the case in
particular in patients with important QRS enlargement linked to major intraventricular conduction
delay. Biventricular pacing, which simultaneously activates both ventricles, may contribute to
correcting the asynchrony and thus improve cardiac performance.
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