Ultrastructural and histological study of endomyocardial biopsies from patients of dilated cardiomyopathy--a comparative evaluation and their clinical correlation.

Morphological studies of dilated cardiomyopathy reveal nonspecific light and electron microscopic features. This study was designed to perform a comprehensive qualitative and semi-quantitative evaluation of histological and ultrastructural parameters in endomyocardial biopsies in 20 cases of DCM. Semi-quantitation of parameters increases the accuracy and precision of evaluation by reducing interobserver variation in assessment. The semi-quantitative score ratios in our study were further correlated with the clinical and hemodynamic data to identify parameter(s) of prognostic significance. In the histological evaluation, myofibre hypertrophy appeared to be the most frequent (95%) and severely affected parameter followed by myocardial degeneration (70%). The ultrastructural features were more diffuse, impressive and severely altered. The most prominent features were mitochondrial degeneration and myofibrillar lysis seen in 100% of our cases. Severe mitochondrial degeneration appeared to be an indicator of poor prognosis in DCM as it was seen in patients with the lowest left ventricular ejection fraction obtained angiographically. Moreover, unlike the light microscopic evaluation, ultrastructural score ratios correlated significantly with the ejection fraction.