111In-antimyosin Fab scintigraphy in cardiovascular diseases

In a multicenter study, a total of 380 patients with myocardial infarction, myocarditis and cardiomyopathy underwent 111In-antimyosin Fab myocardial imaging. 111In-antimyosin Fab was administered intravenously and myocardial images were obtained 48 hours later. Only 3 patients developed mild adverse effects. Human antimouse antibodies were detected in 7 patients. Positive scans in patients with myocardial infarction were seen in 92/119 (77%) within 2 weeks after the onset of myocardial infarction, in 58/71 (82%) at 3-4 weeks, in 20/22 (91%) at 4-8 weeks and 17/31 (55%) thereafter. The location of myocardial damage delineated by 111In-antimyosin Fab imaging was concordant with the infarct location by ECG and coronary angiography. In patients with myocarditis, 111In-antimyosin Fab uptake was positive in 7/12 (58%) within 8 weeks and 6/17 (35%) thereafter. Positive 111In-antimyosin Fab scans were seen in 12/36 (33%) in dilated cardiomyopathy and in 17/19 (89%) in hypertrophic cardiomyopathy. Although the mechanism of persistently positive 111In-antimyosin Fab images in the subacute to chronic stage of myocardial infarction and myocarditis remains to be clarified, 111In-antimyosin Fab may be useful for the detection of the disease and in evaluating the prognosis of patients with cardiomyopathy. (author)