Ischemic heart disease: structural changes of the atria in preinfarction and postinfarction stages

Objective. The aim of this study was to determine atrial structural remodeling during the development of ischemic heart disease.
Material and methods. Quantitative histomorphometric parameters of interstitial collagen network (the percentage volume, perimeter, number of fibers per field and collagen–cardiomyocyte volume ratio) of the atria of 132 autopsied men (mean age 49.7±8.9 years) who had died suddenly (within 6 hours since the onset of terminal heart attack symptoms) due to the first (no postinfarction scars) and repeated (postinfarction scars present) acute “pure” ischemic heart disease were investigated.
Results. The main remodeling feature of the wall of the both atria among ischemic heart disease subjects is hypertrophy of cardiomyocytes and hyperplasia of interstitial fibrillar collagen network with the maintenance of the same proportion of contractile myocardium and fibrillar collagen network volume. This proportion in the case of the left atrium persists in both pre- and postinfarction ischemic heart disease groups, while myocardium of the right atrium in preinfarction group subjects is characterized by an excess increase of collagen network as compared to cardiomyocyte hypertrophy, which levels again with that of the control in postinfarction group.
Conclusions. At preinfarction stage of ischemic heart disease, remodeling of both atria develops and progresses in the left atrium at postinfarction stage in the relationship with increase of left ventricular dysfunction.