[A trial diagnosis of latent dilated cardiomyopathy]

To diagnose latent dilated cardiomyopathy (latent DCM), we performed loading echocardiography with Angiotensin II and ergometer exercise in 41 patients. Twenty-one patients were suspected of having latent DCM because of histories, of heart failure of myocarditis; 10 patients had DCM; and 10 normal persons served as controls. On angiotensin II loading, cardiac function deteriorated in the DCM group, but it was maintained in the normal controls. Nine patients in the latent DCM group showed the same pattern as normals (L1-group), and 12 did as the DCM group (L2-group). Although % fractional shortening, end-diastolic and end-systolic dimensions of the left ventricle did not differ between the L1 and L2-groups, the A/R, the ratio of the pulsed Doppler echocardiogram at the left ventricular inflow tract, was larger and the exercise change of the % fractional shortening and exercise tolerance were less in the L2-group than in the L1-group. Furthermore, the biopsy findings of the L2-group were similar to those of the DCM group in terms of myocardial degeneration, myocardial hypertrophy and interstitial fibrosis. Thus, patients in the L2-group were thought to have a risk for DCM, and were cases of latent DCM. Angiotensin II loading is thought to be useful for diagnosing such cases.