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Endocardial left ventricular pacing improves cardiac resynchronization therapy in chronic asynchronous infarction and heart failure models
- Source :
- Circulation-Arrhythmia and Electrophysiology, 5(1), 191-200. LIPPINCOTT WILLIAMS & WILKINS
- Publication Year :
- 2011
-
Abstract
- 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.
- Subjects :
- Male
medicine.medical_specialty
medicine.medical_treatment
Cardiac resynchronization therapy
Myocardial Infarction
610 Medicine & health
11171 Cardiocentro Ticino
2705 Cardiology and Cardiovascular Medicine
Cardiac Resynchronization Therapy
Electrocardiography
2737 Physiology (medical)
Dogs
Physiology (medical)
Internal medicine
medicine
Animals
cardiovascular diseases
Myocardial infarction
Endocardium
Heart Failure
pacing
medicine.diagnostic_test
Bundle branch block
business.industry
Left bundle branch block
Cardiac Pacing, Artificial
bundle-branch block
medicine.disease
electrophysiology
Disease Models, Animal
Treatment Outcome
Heart failure
Chronic Disease
cardiovascular system
Cardiology
Myocardial infarction complications
Female
Cardiology and Cardiovascular Medicine
business
Follow-Up Studies
Subjects
Details
- ISSN :
- 19413084 and 19413149
- Volume :
- 5
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Circulation. Arrhythmia and electrophysiology
- Accession number :
- edsair.doi.dedup.....c9ead86bd40bdab4fdf00097b965c49e