[Clinical assessment of serum myosin light chain I in patients with dilated cardiomyopathy].
Serum cardiac myosin light chain I (LCI) levels were quantitated using a radioimmunoassay kit in patients suspected of dilated cardiomyopathy (DCM). In this study, 55 patients were evaluated between 1986 and 1991. They were composed of 40 males and 15 females, and their age was 27-75 years (51 +/- 11 years). The patients with renal dysfunction were excluded due to their serum creatinine levels (greater than 2.0 mg/dl). 1) After cardiac catheterization, endomyocardial biopsy and echocardiography, 44 patients were diagnosed as DCM, 2 as ischemic heart disease, 2 as chronic myocarditis, 1 as restrictive cardiomyopathy, 1 as dilated hypertrophic cardiomyopathy, 1 as cardiac amyloidosis, 2 as myopathy, 1 as polymyositis and 1 as hypothyroidism. 2) Only two patients with DCM had elevated LCI. Besides, two patients with myopathy or hypothyroidism had elevated LCI. 3) In the follow-up, one patient died suddenly 6 months later and another showed normal value of LCI four years later. 4) LCI elevation in DCM was not related to either the severity of heart failure or cardiac function and it showed no finding of 201Tl myocardial defect or elevated CPK. 5) The mechanism for elevated LCI in myopathy is related to a cross-reaction with myosin light chain in the skeletal muscle. In hypothyroidism, it may be related to decreased clearance of normal LCI concentration or increased myosin light chain from damaged skeletal muscle. In conclusion, it is evident that the measurement of LCI is not helpful in clinical assessment of patients with DCM, but may be useful in detection of secondary cardiomyopathy.
Tsuda
T
T
First Department of Internal Medicine, Niigata University School of Medicine.
Izumi
T
T
Shibata
A
A
D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000150:complications; D008297:Male; D008875:Middle Aged; D018994:Myosin Light Chains; D009218:Myosins / Q000097:blood*; D011863:Radioimmunoassay
D018994:Myosin Light Chains; C076659:myosin light chain I; D009218:Myosins