TY - JOUR
T1 - Endocardial left ventricular pacing improves cardiac resynchronization therapy in chronic asynchronous infarction and heart failure models
AU - Strik, Marc
AU - Rademakers, Leonard M.
AU - Van Deursen, Caroline J M
AU - Van Hunnik, Arne
AU - Kuiper, Marion
AU - Klersy, Catherine
AU - Auricchio, Angelo
AU - Prinzen, Frits W.
PY - 2012/2
Y1 - 2012/2
N2 - Background-Studies in canine hearts with acute left bundle branch block (LBBB) showed that endocardial left ventricular (LV) pacing improves the efficacy of cardiac resynchronization therapy (CRT) compared with conventional epicardial LV pacing. The present study explores the efficacy of endocardial CRT in more compromised hearts and the mechanisms of such beneficial effects. Methods and Results-Measurements were performed in 22 dogs, 9 with acute LBBB, 7 with chronic LBBB combined with infarction (embolization; LBBB plus myocardial infarction, and concentric remodeling), and 6 with chronic LBBB and heart failure (rapid pacing, LBBB + HF, and eccentric remodeling). A head-to-head comparison was performed of the effects of endocardial and epicardial LV pacing at 8 sites. LV activation times were measured using -100 endocardial and epicardial electrodes and noncontact mapping. Pump function was assessed from right ventricular and LV pressures. Endocardial CRT resulted in better electric resynchronization than epicardial CRT in all models, although the benefit was larger in concentrically remodeled LBBB plus myocardial infarction than in eccentrically remodeled LBBB + HF hearts (19% versus 10%). In LBBB and LBBB + HF animals, endocardial conduction was ≈50% faster than epicardial conduction; in all models, transmural impulse conduction was ≈ 25% faster when pacing from the endocardium than from the epicardium. Hemodynamic effects were congruent with electric effects. Conclusions-Endocardial CRT improves electric synchrony of activation and LV pump function compared with conventional epicardial CRT in compromised canine LBBB hearts. This benefit can be explained by a shorter path length along the endocardium and by faster circumferential and transmural impulse conduction during endocardial LV pacing.
AB - Background-Studies in canine hearts with acute left bundle branch block (LBBB) showed that endocardial left ventricular (LV) pacing improves the efficacy of cardiac resynchronization therapy (CRT) compared with conventional epicardial LV pacing. The present study explores the efficacy of endocardial CRT in more compromised hearts and the mechanisms of such beneficial effects. Methods and Results-Measurements were performed in 22 dogs, 9 with acute LBBB, 7 with chronic LBBB combined with infarction (embolization; LBBB plus myocardial infarction, and concentric remodeling), and 6 with chronic LBBB and heart failure (rapid pacing, LBBB + HF, and eccentric remodeling). A head-to-head comparison was performed of the effects of endocardial and epicardial LV pacing at 8 sites. LV activation times were measured using -100 endocardial and epicardial electrodes and noncontact mapping. Pump function was assessed from right ventricular and LV pressures. Endocardial CRT resulted in better electric resynchronization than epicardial CRT in all models, although the benefit was larger in concentrically remodeled LBBB plus myocardial infarction than in eccentrically remodeled LBBB + HF hearts (19% versus 10%). In LBBB and LBBB + HF animals, endocardial conduction was ≈50% faster than epicardial conduction; in all models, transmural impulse conduction was ≈ 25% faster when pacing from the endocardium than from the epicardium. Hemodynamic effects were congruent with electric effects. Conclusions-Endocardial CRT improves electric synchrony of activation and LV pump function compared with conventional epicardial CRT in compromised canine LBBB hearts. This benefit can be explained by a shorter path length along the endocardium and by faster circumferential and transmural impulse conduction during endocardial LV pacing.
KW - Bundle-branch block
KW - Cardiac resynchronization therapy
KW - Electrophysiology
KW - Heart failure
KW - Pacing
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U2 - 10.1161/CIRCEP.111.965814
DO - 10.1161/CIRCEP.111.965814
M3 - Article
C2 - 22062796
AN - SCOPUS:84858324875
VL - 5
SP - 191
EP - 200
JO - Circulation: Arrhythmia and Electrophysiology
JF - Circulation: Arrhythmia and Electrophysiology
SN - 1941-3149
IS - 1
ER -