The prognostic use of serum concentrations of cardiac troponin-I, CK-MB and myoglobin in patients with idiopathic dilated cardiomyopathy.

OBJECTIVE:To examine the association between survival and serum concentrations of cTnI, CK-MB, and myoglobin in patients with idiopathic dilated cardiomyopathy (IDC). BACKGROUND:It has been suggested that elevated circulating biomarkers of myocardial damage such as cardiac troponin-I (cTnI), creatine kinase MB (CK-MB) and myoglobin are independent risk factors for mortality in patients with heart failure, and recent studies, although limited, showed that there was a potential association between cTnI and the prognosis of patients with dilated cardiomyopathy (DCM). METHODS:A cohort study was undertaken in 310 patients with IDC. Standard demographic information, transthoracic echocardiography, and routine blood tests were obtained shortly after hospital admission. Outcome was assessed with all-cause mortality. RESULTS:Among the 310 patients studied, 61 (19.7%) died during a mean follow-up of 2.2 years. There was a significant difference in the all-cause mortality rate between patients with serum cTnI >0.05 ng/mL and with cTnI ≤ 0.05 ng/mL (37.5% vs 15%, log-rank χ(2) = 18.423, P < 0.001). After adjustment for other factors associated with prognosis at baseline, serum cTnI >0.05 ng/mL, QRS duration, NYHA functional class and systolic blood pressure predicted all-cause mortality in patients with IDC. There was no association between circulating CK-MB and myoglobin levels and all-cause mortality in the studied IDC patients. CONCLUSION:Serum concentrations of cTnI but not CK-MB or myoglobin are an independent predictor of all-cause mortality in patients with IDC.