Thrombolytic therapy and intravenous heparin in acute myocardial infarction do not affect the incidence of left ventricular mural thrombus formation.

patients (27 % ) had inflammatory heart disease. The other patients showed normal histology (eight patients, 36 % ) or increased fibrosis (seven patients, 32 % ), which was accompanied by pathologic lipomatosis in only three patients (14%). In the present study we often found significant fibrolipomatosis (66 % ), leading to the diagnosis of arrhythmogenic right ventricular dysplasia. This high incidence of right ventricular dysplasia may relate to the more extensive procedure used, which obviously may increase the likelihood of finding clinically significant microscopic abnormalities. It may be objected that the high incidence may have been the result of less strict pathoanatomic criteria, compared with those used by other investigators.3 In addition, lipomatosis may be considered to be a normal observation in endomyocardial right ventricular biopsies. However, in accordance with the report by Mehta et al.,ll we considered the presence of adipose tissue significant only when it was accompanied by an increase in fibrous tissue. Identification of a specific cause of idiopathic ventricular fibrillation has consequences for diagnosis and prognosis. Patients with a reversible cause, such as inflammatory heart disease, may especially have a favorable prognosis.6 On the other hand, the prognosis may be rather variable in patients with right ventricular dysplasia or other cardiomyopathies. This explains the differences in prognosis of survivors of sudden death who have no cardiac disease in studies that did not use endomyocardial biopsies. The clinical value and feasibility of extensive right ventricular endomyocardial biopsy procedures in idiopathic ventricular fibrillation remain to be established in a larger cohort of patients. An extensive biopsy procedure could implicate a higher complication risk than a standard procedure, especially in the case of diseased right ventricles. During the biopsy procedures, care was taken to prevent deep transmural biopsies. The absence of complications in the present report may relate to the fact that biopsies were taken from patients in the early stages of the disease whose ventricular tissue was still relatively well preserved.