The Clinical Significance Of Serum Cardiac Troponin â…  Changed In Patients With Dilated Cardiomyopathy With Chronic Systolic Heart Failuer

Objective: To investigate the serum cardiac troponin I (cTnI) level in patients with dilated cardiomyopathy (DCM) with chronic systolic heart failure, and to analysis the theory and clinical significance of serum cTnI elevated in DCM patients.Methods: Serum cTnI,creatine kinase (CK) and it isoenzyme (CK-MB) was measured in 73 patients with DCM (mean age 52.3±13.0 years, New York Heart Association functional class III-IV , DCM group ) on admission for worsening heart failure and 5-7days after initiation of treatment to stabilize heart failuer, and in 54 hospitalized control subjects without known cardiac disease (hospitalized control group). cTnI was measured by chemical immunofluoreses and upper limits was 0.08ug/L. CK was measured by immunoturbidime and normal value was 35-145IU/L. CK-MB was measured by immunoturbidime and upper limits was 25IU/L. Left ventricular diastolic dimension (LVDd) and left ventricular ejection fraction (LVEF) was detected by a HP Sonos 5500 color echocardiographic diagnostic apparatus in DCM group.Results:(1)The serum level of cTnI in DCM group was 0.315±0.147μg/L (range 0.01～0.75μg/L). The serum level of cTnI showed significant statistical difference comparing with that of hospitalized control group(0.315±0.147μg/L vs 0.014±0.006μg/L, P<0.01). (2) The serum level of cTnI in DCM patients assessed by NYHA class III and IV was 0.158±0.104μg/L : 0.352±0.141μg/L, respectively. Mean cTnI level was significantly higher in patients of class IV than those of class III (P<0.01). (3)The serum level of cTnI in DCM group with LVEF≤35% and LVEF>35% was 0.368±0.137μg/L : 0.162±0.082μg/L, respectively. Mean cTnI level in two groups showed statistical difference (P<0.05). (4) The level of cTnI had a negative correlation with LVEF in DCM group (r=-0.536, P<0.05). (5) Clinical conditions of DCM group improved with declining of cTnI (0.308±0.111μg/L) after conventional treatment for congestive heart failure, but the serum level of cTnI didn't show statistical difference, and was still significantly higher than that of hospitalized control group (0.308±0.111μg/L vs 0.014±0.006μg/L, P<0.01).Conclusions:1. The serum cTnI level elevated in DCM patients with advanced chronic systolic heart failure is highly indicative of myocardial injury and necrosis.2. The serum cTnI level was related with cardiac function of DCM patients. The serum cTnI level had a negative correlation with LVEF and the higher level of cTnI was correlated with the severity of heart failure in DCM patients.3. Persistently increased cTnI in DCM after conventional treatment for congestive heart failure suggests that subclinical myocyte degeneration and necrosis continues and ultimately results in cardiac decompensation.