Pathology of idiopathic cardiomegaly in Jamaica.

Twenty-one cases of idiopathic cardiomegaly which came to necropsy have been reviewed.A Investigations included injection and x-ray studies, careful microscopical examination and skip serial sectioning of the conduction systems.The obvious feature was gross cardiomegaly in the absence of atheroma of the large coronary vessels and an associated fibrosis of the right and left bundle-branches.Three hearts showed thickening of the intramural vessels of 8o0 to 4OOt di- ameter.We suggest that such changes may be one of the causes of the ischaemic electrocardiographic findings reported in previous epidemiological surveys.In I963 Stuart and Hayes described patients with cardiomegaly of unexplained aetiology seen clinically and at necropsy at the Univer- sity Hospital of the West Indies (U.H.W.I.) _. in Jamaica.This paper suggested that a form ofidiopathic cardiomegaly occurred with some -_ frequency in the Jamaican community.Their patients were mainly from the lower income group, the average length of illness being i8 months.In the majority of patients there was a gradual downhill course though in the early stages congestive cardiac failure was easily controlled.Pulmonary and systemic emboli from cardiac mural thrombi were not uncommon.Hypertrophy of the heart was an -incidental finding in those patients not pre- senting in congestive cardiac failure.Three clinical types were described: (i) simulating ischaemic heart disease; (2) simulating valvu- lar disease; and (3) a constrictive type simu- lating constrictive pericarditis.At necropsy the hearts showed conspicuous uniform en- largement and dilatation of all four chambers.Myocardial fibrosis was nonspecific and cellular infiltrate was mild or absent.In 9 of the 29 cases there was associated hepatic cirrhosis or fibrosis.More recent epidemiological studies in *Jamaica showed an unexpectedly large num- ber of subjects with electrocardiographic signs of ischaemic heart disease (Fodor et al., I964).Their survey of two communities in a rural and suburban area showed a higher prevalence of such changes than were found Received I April 1970.tion, I968), i.e. excluding the known causes of heart enlargement.,