Premium
The aging rabbit heart as a model for cardiac aging
Author(s) -
Cooper Leroy Leon,
Odening Katja E.,
Ziv Ohad,
Chaves Lenny,
Schofield Lorraine,
Choi BumRak,
Koren Gideon
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.595.6
Subject(s) - ventricle , cardiology , medicine , purkinje fibers , qrs complex , electrical conduction system of the heart , electrophysiology , electrocardiography
Objective To characterize of the effect of aging on His‐Purkinje and ventricular conduction. Methods Old (4 – 5.5 years) and young (5 – 8 months) female NZW rabbits were subjected to transvenous catheter‐based in vivo electrophysiological (EP) and hemodynamic studies. Mason Trichrome staining was used to evaluate differences in fibrosis. Results Among the old cohort we observed a cumulative incidence of sudden death (SD) of 5%. EP studies revealed significantly prolonged QRS complexes (old: 64.8ms ± 3.7 vs. young: 49.8ms ± 0.3, p=0.002) and prolonged His‐to‐Ventricle intervals in old rabbits (old: 31.9ms ± 1 vs. young: 23ms ± 1, p<0.0001), indicating a slowed conduction through the His‐ Purkinje. Also, older rabbit hearts were more easily VF‐inducible (7/8) than young hearts (3/12, p<0.05), indicating an underlying substrate for arrhythmias. Substantial slowing of conduction velocity (CV) was seen transverse to fiber orientation in old compared to young (0.2±0.03m/s vs 0.33± 0.07m/s; p<0.05). VF in old hearts demonstrated repetitive formation of lines of functional conduction block parallel to fiber orientation. Old hearts showed more pronounced fibrosis in the ventricle and the septum that appeared to infiltrate the myocardium from the epicardiaum towards the subepicardium. Conclusion Increase in anisotropic conduction due to fibrosis likely plays a key role in the pathogenesis of VF in old hearts.