Myocardial fibres in pulmonary veins--possible compensatory factor in dilated cardiomyopathy

It is well known in the literature that myocardial tissue is present in different degrees in pulmonary veins, but the eventual role of this myocardial tissue in pulmonary veins is not very clear at this moment. We presumed that one of the compensatory mechanisms in heart failure could be represented by the development of this myocardial tissue in the pulmonary veins. We studied the extension of this myocardial tissue in patients with dilated cardiomyopathy (DCM). We performed a histologic examination of the myocardial tissue from the pulmonary veins, in patients with heart failure in advanced stages. These patients died in the hospital and we obtained the pulmonary tissue for examinations during the autopsy. At the border between the media and the adventitia of the pulmonary vein, the myocardial tissue is present and is well developed. Some of the fibers have a sinuous course, others present a longitudinal aspect, especially in the external layers. In some sections bundles and bands of muscle fibers are present. In the sections where no myocardial tissue was shown, the smooth muscular fibers were very numerous. The necroptic histologic studies showed different degrees of hypertrophy of the myocardial tissue in the pulmonary veins, in the patients with heart failure in advanced stages. We observed that dilatation degree of cardiac cavities and decrease of the ejection fraction correlates with hypertrophy degree of the myocardial tissue in the pulmonary veins. This can be an argument for the compensatory role of this hypertrophy.