Objective: Compared with other myocardial enzymes like CK and CK-MB, this study investigates the theoretical basis of whether or not cardiac Troponin I can be used as a diagnostic index of dilated cardiomyopathy. Clinical significance of serum cTnI level of patients with dilated cardiomyopathy (DCM) and its mechanism are studied further.
Methods: Firstly, we detected serum cTnI, CK and CK-MB level of patients with DCM in hospital, then detected the change of serum cTnI, CK and CK-MB level of patients with DCM under different cardiac function levels and left ventricular ejections. Then, patients were divided into positive group when cTnI>0.05 μg/L and into negative when cTnI<0.05 μg/L. Each group consisted of 30 patients. We detected patients’ left atrial diameter (LA), left ventricular end diastolic (LVED), left ventricular end systolic (LVES) and left ventricular ejection fraction (LVEF) by methods of echocardiography, and monitored cardiac arrhythmia with conventional ECG and 24 h dynamic electrocardiogram.
Results: Serum cTnI level of patients in DCM group was significantly higher than that of patients in control group (p<0.01).Serum cTnI level of class IV cardiac function patients was significantly higher than that of class III function (p<0.01). Serum cTnI level of LVEF ≤ 35% patients was higher than that of LVEF>35% patients. There was no significant difference in patients’ level of CK or CK-MB, indicating that cTnI level is better indicator for molecular diagnosis of patients with DCM. We further divided patients with DCM into positive and negative group by level of serum cTnI. Results demonstrated that cardiac function, LVED and LVES of patients in positive group were significantly higher than those of patients in negative group while LVEF was lower (p<0.05). Patients in the negative group were prone to ventricular arrhythmia while those in positive group were prone to atrial arrhythmia and intraventricular block.
Conclusion: Level of serum cTnI can be used as indicator for molecular diagnosis of patients with DCM. Increase of serum cTnI in patients with DCM indicates severe myocardial damage and unfavorable prognosis.