Fibrosis, myocyte degeneration and heart failure in chronic experimental aortic regurgitation.
Myocardial fibrosis and myocyte degeneration have been reported in patients with chronic aortic regurgitation (AR), and may be related to the pathophysiology of congestive heart failure (CHF) in this disease. To define the relationship between myocardial histopathologic variations and CHF in chronic AR, we performed gross and microscopic evaluations of postmortem tissue from a rabbit model of chronic AR manifesting left ventricular (LV) responses to AR similar to those in humans. Moderate-to-severe chronic AR (echocardiographic regurgitant fraction = 52 +/- 13%) was induced by closed-chest aortic valve perforation in 11 New Zealand White rabbits; 5 control rabbits were sham operated. Six of the 11 AR rabbits died 1.5 +/- 0.8 years (range 0.6-2.8 years) after AR induction; all 6 had gross and histologic anatomic evidence of CHF at necropsy. The remaining 5 AR rabbits survived until sacrifice at 2.9 +/- 0.1 years of AR; none had pathologic evidence of CHF. Cardiac hypertrophy and the extent of LV fibrosis and myocyte necrosis all were greatest among the 6 AR CHF rabbits. No inflammatory response was apparent in any animal. Moderate-to-severe chronic experimental AR frequently results in CHF which is strongly associated with myocardial fibrosis and necrosis, without evidence of inflammation. These histopathologic variations may be pathophysiologically related to CHF development.
Division of Cardiovascular Pathophysiology, Cornell University Medical College, New York Hospital- Cornell Medical Center, New York, NY 10021, USA.
S K
SK
Liu
N R
NR
Magid
P R
PR
Fox
S M
SM
Goldfine
J S
JS
Borer
D000818:Animals; D001022:Aortic Valve Insufficiency / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D004452:Echocardiography; D004719:Endomyocardial Fibrosis / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D006333:Heart Failure / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D009200:Myocardial Contraction; D010784:Photomicrography; D011817:Rabbits; D016277:Ventricular Function, Left