Prevention of adverse electrical and mechanical remodeling with biventricular pacing in a rabbit model of myocardial infarction.
BACKGROUND
Biventricular (BIV) pacing can improve cardiac function in heart failure (HF).


OBJECTIVE
This study sought to investigate the mechanisms of benefit of BIV pacing using a rabbit model of myocardial infarction (MI).


METHODS
New Zealand White rabbits were divided into 4 groups (sham-operated [C], MI with no pacing [MI], MI with right ventricular pacing [MI+RV], and MI with BIV pacing [MI+BIV]) and underwent serial electrocardiograms and echocardiograms. At 4 weeks, hearts were excised and tissue was extracted from various areas of the left ventricle (LV).


RESULTS
Four weeks after coronary ligation, BIV pacing prevented systolic and diastolic dilation of the LV as well as the reduction in its fractional shortening, restored the QRS width and the rate-dependent QT intervals to their baseline values, and prevented the decline of the ether-a-go-go (Erg) protein levels. This prevention of remodeling was not documented in the MI+RV groups.


CONCLUSIONS
In this rabbit model of BIV pacing and MI, we show prevention of adverse mechanical and electrical remodeling of the heart. These changes may underlie some of the benefits seen with BIV pacing in HF patients with more severe LV dysfunction.
Saba
Samir
S
Cardiovascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA. sabas@upmc.edu
Mathier
Michael A
MA
Mehdi
Haider
H
Gursoy
Erdal
E
Liu
Tong
T
Choi
Bum-Rak
BR
Salama
Guy
G
London
Barry
B
D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000294:innervation* / Q000601:surgery; D017379:Hypertrophy, Left Ventricular / Q000503:physiopathology / Q000517:prevention & control*; D023421:Models, Animal; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011817:Rabbits; D014463:Ultrasonography