Etiology and Phenotypes of Cardiomyopathy in Southern Africa: The IMHOTEP Multicenter Pilot Study

Background: Cardiomyopathies are an important cause of heart failure in Africa yet there are limited data on etiology and clinical phenotypes. Objectives: The IMHOTEP (African Cardiomyopathy and Myocarditis Registry Program) was designed to systematically collect data on individuals diagnosed with cardiomyopathy living in Africa. Methods: In this multicenter pilot study, patients (age ≥13 years) were eligible for inclusion if they had a diagnosis of cardiomyopathy or myocarditis. Cases were grouped and analyzed according to phenotype; dilated cardiomyopathy (DCM) including myocarditis and peripartum cardiomyopathy, hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), and restrictive cardiomyopathy (RCM). Results: A total of 665 unrelated index cases (median age 35 [27-44] years; 51.1% female) were recruited at 3 centers in South Africa and 1 center in Mozambique. DCM (n = 478) was the most common type of cardiomyopathy, accounting for 72% of the cohort; ACM (n = 78), HCM (n = 70), and RCM (n = 39) were less frequent. While the age of onset and sex distribution of HCM and ACM were similar to European and North American populations, DCM and RCM had a younger age of onset and occurred more frequently in women and those with African ancestry. Causes of cardiomyopathy were diverse; familial (27%), nonfamilial/idiopathic (36%), and secondary (37%) etiologies were observed. Conclusions: In the largest study of cardiomyopathy to-date on the African continent, we observe that DCM is the dominant form of cardiomyopathy in Southern Africa. The age of onset was significantly younger in African patients with notable sex and ethnic disparities in DCM.