The Rationale, Design And Implementation Of The African Cardiomyopathy And Myocarditis Registry
Background. Causes of heart failure in Africa are largely non-ischaemic: hypertension, rheumatic heart disease and cardiomyopathy. Cardiomyopathies pose a great challenge because of poor prognosis and high prevalence in low- and middle-income countries with limited access to specialised care. Little is known about aetiology or outcomes of cardiomyopathy in Africa. Method. The African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) is a pan-African multi-centre, hospital-based cohort study. It aims to describe the clinical characteristics, aetiology, genetics, management and outcome of cardiomyopathies in children and adults. Index patients were recruited as either incident (new) or prevalent (existing) cases, and family screening was conducted in selected cases. Several sub-studies were conducted at the initiating centre, including; outcome studies on prevalent cases incorporated into IMHOTEP, a cardiovascular magnetic resonance (CMR) study on incident cases, and a clinical genetics study on families. Results. The pilot phase was commenced in Cape Town (February 2015), followed by staggered initiation at 6 further sites. Over 600 index patients have been recruited to the registry to date. Preliminary data on the first 99 incident adult cases recruited at the initiating site, showed that dilated cardiomyopathy (DCM; n=67) was commonest, followed by hypertrophic (HCM; n=13), left ventricular noncompaction (LVNC; n=11), restrictive (RCM; n=4) and arrhythmogenic right ventricular (ARVC; n=4) cardiomyopathies. Cardiomyopathy occurred predominantly in mixed race (46%) and black (41%) Africans, and more frequently in females (54%). Mean age of presentation was 36.8 ±12.5 years. CMR performed in incident cases (67/99, 68%) proved diagnostically useful, however, acute myocarditis was only reported in one individual. In addition, prevalent cases with ARVC and DCM were enrolled from two existing studies at the initiating centre. Except for fewer (24%) genotype positive (PKP2 20%, CDH2 4%) individuals with ARVC (n=70), the baseline characteristics and diagnostic criteria were similar to what has been reported internationally. Transplant-free survival probability at 1-year, 5-years and 10-years was 98.5%, 90.7%, and 80.8% respectively in ARVC (median survival time 9.0 years) and there were no significant differences in survival between those with and without implantable cardioverter defibrillators [p=0.27]. In the prevalent DCM cohort (n=133), transplant-free survival probability was 93.4%, 82.2% and 73.1% at 1-year, 5-years and 10-years respectively, with a median survival time of 5.3 years. The age of onset (34.8 ±11.0 years) and death (41.5 ±9.6 years) were significantly younger in our DCM patients compared to European cohorts. Thirty-five families were recruited (16 genotype positive, 19 genotype unknown) with autosomal dominant inheritance observed in 94.3% families. Conclusion. IMHOTEP is the first multi-centre registry for cardiomyopathy in Africa. Preliminary data suggests an earlier age of onset compared to European cohorts and that DCM is the most common form of cardiomyopathy in South Africa. Molecular genetic analysis will provide vital and novel data on the genetic causes of cardiomyopathy in Africans.