REMODELING AFTER MYOCARDIAL-INFARCTION IN HUMANS IS NOT ASSOCIATED WITH INTERSTITIAL FIBROSIS OF NONINFARCTED MYOCARDIUM

Objectives, This study was specifically designed to evaluate whether n oninfarcted hypertrophic myocardium in patients with end stage heart f ailure after myocardial infarction (MI) is associated with an increase in interstitial fibrous tissue. Background. Postinfarction remodeling consists of complex alterations that involve both infarcted and nonin farcted myocardium, The question arises whether ventricular dysfunctio n is due to physical events, such as inadequate myocardial hypertrophy to compensate for increased tangential wall stress, or is caused by t he development of progressive interstitial fibrosis in noninfarcted my ocardium. Methods. Fifteen hearts were obtained as cardiac explants (n = 13) or at autopsy (n = 2) from patients with end stage coronary art ery disease, Sixteen normal hearts served as reference hearts, Samples were taken from the left ventricular (LV) wall that contained the inf arcted area, the border area and noninfarcted myocardium remote from s car areas, Collagen was quantified biochemically and microdensitophoto metrically. Collagen type I and III ratios were analyzed by using the cyanogen bromide method and immunohistochemical staining, followed by microdensitophotometric quantification. Results. In noninfarcted myoca rdium remote from the scar areas, total collagen levels and collagen t ype I/III ratios did not differ statistically from those in reference hearts, These observations contrasted with high total collagen content and high collagen type I/III ratios in scar and border areas. Conclus ions. Remodeling of LV myocardium after MI in patients with end stage heart failure is not necessarily associated with interstitial fibrosis in noninfected hypertrophic myocardium remote from scar areas, This f inding raises questions regarding therapeutic interventions designed t o prevent or retard the development of interstitial fibrosis. (C) 1997 by the American College of Cardiology.