Search for Coxsackievirus B3 RNA in idiopathic dilated cardiomyopathy using gene amplification by polymerase chain reaction

Dilated cardiomyopathy and myocarditis in Kenya: an endomyocardial biopsy study

We have studied, by light and electron microscopy, left ventricular endomyocardial biopsy specimens from 18 African patients (14 men) with idiopathic dilated cardiomyopathy in Nairobi. Nine patients (50%) had evidence of healing myocarditis, that is the presence of a mild inflammatory cell infiltration within the myocardium. Interstitial fibrosis was prominent in five patients (28%) and in all 18 specimens there were hypertrophied muscle fibres. Therefore, half of the patients with idiopathic dilated cardiomyopathy had histological signs of a previous myocarditis. There was no serological evidence of a previous or recent coxsackie infection or any other common viral infections. It seems probable that the myocarditis was due to an inappropriate immunological reaction to myocardial muscle.

Similar prevalence of enteroviral genome within the myocardium from patients with idiopathic dilated cardiomyopathy and controls by the polymerase chain reaction

OBJECTIVE

To assess the prevalence and significance of enteroviral genome within myocardial biopsy specimens taken from patients with idiopathic dilated cardiomyopathy and from controls.

DESIGN

Prospective evaluation of myocardial tissue for the presence of an enteroviral genome by the polymerase chain reaction.

SETTING

A tertiary referral centre for patients with idiopathic dilated cardiomyopathy.

PATIENTS

Tissue for the study came from 50 consecutive patients with dilated cardiomyopathy, 41 with other forms of heart disease and 34 from coroners' necropsy cases.

RESULTS

Enteroviral genome was detected in 6/50 (12%) patients with dilated cardiomyopathy and 13/75 (17%) of the controls (not significant). No differences were seen between dilated cardiomyopathy patients with or without myocardial enteroviral genome in respect of age; duration of symptoms; proportion of patients with a premorbid acute viral illness, excess alcohol consumption, or hypertension; New York Heart Association functional class; measures of left ventricular function; or endomyocardial histology. Within the control group enteroviral genome was detected in 3/15 (20%) patients with ischaemic heart disease, 2/19 (10.5%) with valvar heart disease, 1/5 (20%) with specific heart muscle disease, 0/2 (0%) with congenital heart disease, and 7/34 (20.6%) cases of sudden death. During 2-52 month follow up (mean 22) 15/44 (34%) patients without myocardial enteroviral genome and 2/6 (33%) with myocardial enteroviral genome died suddenly or required orthotopic heart transplantation for progressive heart failure.

CONCLUSIONS

These findings do not support the hypothesis that persistent enteroviral infection is of pathogenic or prognostic importance in dilated cardiomyopathy but they are consistent with enterovirus being a common environmental pathogen.