Interstitial fibrosis in the dilated non-ischaemic myocardium.

Coronary artery occlusion and a variety of inflammatory disorders are followed by focal or segmental areas of fibrous scarring. The causes of interstitial fibrosis are less clear. Variable but sometimes dense interstitial fibrosis is seen in dilated cardiomyopathy. Some reports suggest that interstitial fibrosis is also increased in non-infarcted myocardium from hearts with ischaemic scars. Because of current interest in the pathophysiology of ventricular dilatation, we compared the interstitial collagen content of the left and right ventricles in dilated and undilated hearts of subjects without significant coronary artery occlusion. Our hypothesis was that we would find histological evidence of increased interstitial collagen content in dilated hearts.