Ultrastructural features of cardiomyocytes in dilated cardiomyopathy with initially decompensated heart failure as a predictor of prognosis

Abstract

Aims: The aim of the present study was to clarify the significance of myocardial ultrastructural changes in patients with dilated cardiomyopathy (DCM).

Methods and results: Endomyocardial biopsy of the left ventricle was performed in 250 consecutive DCM patients (54.9 ± 13.9 years, 79% men), presenting initially as decompensated heart failure (HF). Myofilament changes of cardiomyocytes were evaluated by electron microscopy and compared with clinical and morphometric data. Mortality and HF recurrence were evaluated during the follow-up period. During the follow-up period (4.9 ± 3.9 years), 24 patients (10%) died and 67 (27%) were readmitted because of HF recurrence, including those who had died because of HF. Myofilament changes, classified as either focal derangement of myofilaments (sarcomere damage) or diffuse myofilament lysis (disappearance of most sarcomeres in cardiomyocytes), were identified in 164 patients (66%). Multivariate analysis identified a family history of DCM [hazard ratio (HR) 4.763; 95% confidence interval (CI) 1.012-12.518], atrial fibrillation (HR 6.132; 95% CI 2.188-17.180), haemoglobin level (HR 0.685; 95% CI 0.528-0.889), and diffuse myofilament lysis (HR 4.048; 95% CI 1.427-11.481) as independent predictors of mortality. A family history of DCM (HR 2.268; 95% CI 1.276-4.030), haemoglobin level (HR 0.876; 95% CI 0.785-0.979), focal derangement of myofilaments (HR 7.431; 95% CI 2.916-18.934), and diffuse myofilament lysis (HR 6.480; 95% CI 2.403-17.473) were predictors of readmission due to HF recurrence.

Conclusions: In DCM patients with first-decompensated HF, myofilament changes are strongly associated with mortality and HF recurrence.

Keywords: Dilated cardiomyopathy; Electron microscopy; Endomyocardial biopsy; Heart failure; Myofilament changes.