Prevalence of Exclusively Right-Sided Endomyocardial Fibrosis among Patients with Heart Failure in Equatorial Guinea

Endomyocardial fibrosis (EMF) is a common restrictive cardiomyopathy of unknown etiology, endemic to regions close to the equator. According to previously published reports, the disease affects only the right ventricle (RV) 10-28% of patients with endomyocardial fibrosis. The aims of this study were to determine the prevalence of EMF among patients with heart failure in Equatorial Guinea, and to describe its clinical manifestations. We used transthoracic echocardiography to determine the prevalence of EMF among 50 patients with newly diagnosed heart failure. We compared the demographic data, clinical features and eosinophilic counts in patients with EMF and patients with other forms of heart failure. During a study period of nine months ten patients were diagnosed with EMF, accounting for 20% of the patients diagnosed with heart failure. Curiously, all ten patients had exclusive right-sided disease. The average time from the onset of symptoms to diagnosis was 6.1±2.0 years (range 3-9 years), implicating a much better prognosis than previously reported. Eosinophil count was not higher in patients with EMF when compared to other patients with heart failure. The exclusive involvement of the right ventricle in ten consecutive patients, and the relatively long survival after the onset of symptoms, hint towards a specific variant of the disease in Equatorial Guinea.