Cardiomyopathies and myocardial disorders in Africa: present status and the way forward

Abstract

A review of heart diseases in Africa shows that the cardiomyopathies continue to be important causes of morbidity and mortality in the population. Hypertension remains the commonest cause of myocardial disease, followed by the cardiomyopathies. Ischaemic heart disease continues to be rare. Of the cardiomyopathies, dilated cardiomyopathy (DCM) is still the commonest. A large proportion of patients diagnosed with DCM in Africa have been shown to be cases of hypertensive heart failure, with varying degrees of myocardial dysfunction. Hypertrophic cardiomyopathy, which in the past was thought to be rare among Africans, has been shown to have the same prevalence as in other parts of the world. Moreover it is now known to be a genetic disorder. Endomyocardial fibrosis has become rare in communities where it used to be common. Its aetiology continues to be elusive. Arrhythmogenic right ventricular cardiomyopathy has been reported among Africans but there are no reports of left ventricular non-compaction or the ion channelopathies from Africa. Lenegre disease and the long-QT syndromes are well-known entities in clinical practice in Africa although long-QT in Africa is associated with potassium deficiency arising from prolonged treatment with diuretics. Left ventricular non-ischaemic aneurysms still occur but are rare. In view of these, a new classification of myocardial disorders was proposed for Africa.

Fig. 1

Causes of heart failure in Nigerians at the University College Hospital, Ibadan between 1968 and 1969 (Carlisle and Ogunlesi 1972). B. Causes of heart failure in the same ethnic group in the year 2010 compared with the 1972 data. HHF = hypertensive heart failure; RHDX = rheumatic heart disease; DCM = dilated cardiomyopathy; EMF = endomyocardial fibrosis; CP = cor pulmonale; IHDX = ischaemic heart disease.

Fig. 2

Hypertrophic cardiomyopathy; B. dilated cardiomyopathy; C. endomyocardial fibrosis.

Fig. 3

The consequences of myocardial fibrosis on the heart of patients with arterial hypertension, modified from Diez et al. Nature Clin Pract Cardiovasc Med 2005; 2(4): 209–216.

Fig. 4

Representation of progression of the left ventricle in hypertensive patients, from concentric hypertrophy with a small cavity, to concentric hypertrophy with a large cavity, to a destroyed myocardium unable to sustain a high blood pressure.

Fig. 5

Davies’ representation of endomyocardial fibrosis.