Rationale and design of the African Cardiomyopathy and Myocarditis Registry Program: The IMHOTEP study

Endomyocardial fibrosis: recent advances and future therapeutic targets

Endomyocardial fibrosis, first described >75 years ago, is a cause of restrictive cardiomyopathy with an unclear aetiopathogenesis that is most commonly found in children and adolescents from tropical regions of Africa, Asia and South America. The epidemiological trends of this cardiomyopathy are difficult to ascertain. The characteristic hallmark of endomyocardial fibrosis is ventricular fibrosis that causes diastolic dysfunction and atrioventricular regurgitation. Although advances in medical treatment for heart failure and more tailored surgical techniques to treat the condition have increased survival, the outcomes in affected patients remain poor. A major focus of research is the identification of biomarkers of preclinical disease and new therapeutic targets. Collaborative multidisciplinary research and cross-learning from other fibrotic conditions should impart knowledge and help to improve the survival rates and the quality of life of patients with endomyocardial fibrosis.

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.

Global burden of myocarditis in youth and middle age (1990-2019): A systematic analysis of the disease burden and thirty-year forecast

BACKGROUND

Myocarditis is increasingly recognized as a critical health issue, particularly among youth and middle-aged populations. This study aims to analyze the global burden and trends of myocarditis in these age groups to emphasize the need for region-specific prevention and treatment strategies.

METHODS

Using data from the Global Burden of Disease (GBD) study (1990-2019), we evaluated the age-standardized rates (ASR) of myocarditis in individuals aged 10 to 54 years. We calculated average annual percentage changes (AAPC) and estimated annual percentage changes (EAPC). Additionally, we examined the correlation between myocarditis incidence and the Human Development Index (HDI) and Socio-demographic Index (SDI). Age and sex trends in myocarditis were analyzed, and Bayesian age-period-cohort (BAPC) models were used to forecast prevalence trends up to 2050.

RESULTS

The High-income Asia Pacific region had the highest ASR of myocarditis, while North Africa and the Middle East had the lowest. North Africa and the Middle East also experienced the fastest average annual growth in ASR, whereas High-income North America saw the most significant decline. Correlational analysis showed that countries with a high SDI exhibited higher myocarditis ASR. The burden of myocarditis was greater among males than females, with this disparity increasing with age. Projections indicate a stable trend in the incidence of myocarditis among the youth and middle-aged population up to 2050, although the total number of cases is expected to rise.

CONCLUSION

Our study reveals a significant upward trend in myocarditis among youth and middle-aged populations, highlighting the urgency for early monitoring and preventative strategies.

Adherence to heart failure treatment in patients with peripartum cardiomyopathy

AIMS

Peripartum cardiomyopathy (PPCM) is characterized by left ventricular (LV) dysfunction developing towards the end of pregnancy or in the first months postpartum. Although about 60% of women with PPCM (the majority of which are prescribed evidence based heart failure [HF] medications) show LV recovery within 6 to 12 months, others remain with persistently impaired LV function. Poor adherence to medical therapy represents a major cause of avoidable hospitalizations, disability, and death in other cardiovascular conditions. In this study, we aimed to determine drug adherence to HF therapy among women with PPCM and to identify possible associations between drug adherence and LV recovery, functional status and psychological well-being.

METHODS AND RESULTS

In this single-centre, prospective, observational study, we included 36 consecutive women with PPCM. Adherence to HF treatment was assessed by (i) verifying the collection of pharmacy refills and (ii) using liquid chromatography high-resolution mass spectrometry (LC-HRMS). Participants were thereby classified as 'adherent' (i.e. all prescribed HF drugs were detectable by LC-HRMS), 'partially adherent' (i.e. at least one prescribed drug detectable) or 'non-adherent' (i.e. none of the prescribed drugs detectable). Health state index scores were assessed by EQ-5D-5L and HADS-A/D (for anxiety/depression). Patients' median age was 32.4 years (IQR 27.6-36.1). At the adherence visit (which occurred at a median of 16 months [IQR 5-45] after PPCM diagnosis), prescription included beta-blockers (77.8%), angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (75%), mineralocorticoid receptor antagonists (47.2%) and loop diuretics (95.2%). Less than two thirds of patients (63.9%) collected all their pharmacy refills in the 6 months prior to adherence visit. According to LC-HRMS, 23.5% participants were classified as adherent, 53.0% as partially adherent, and 23.5% as non-adherent. Adherence was associated with significantly lower LVEDD at follow-up (47 mm [IQR 46-52), vs. 56 mm [IQR 49-64] with partial adherence, and 62 mm [IQR 55-64] with non-adherence, P = 0.022), and higher LVEF at follow-up (60% [IQR 41-65]), vs. partially adherence (46% [IQR 34-50]) and non-adherence (41.0% [IQR 29-47], P = 014). Adherent patients had a lower overall EQ- 5D score (5.5 [IQR 5-7.5], vs. 6 [IQR 5-7] in partially adherent, and 10 [IQR 8-15] in non-adherent patients, P = 0.032) suggestive of a better self-rated health status.

CONCLUSIONS

Adherence to HF therapy was associated with favourable LV reverse remodelling in PPCM and better self-rated health status. Our study highlights the importance of drug adherence for functional recovery. Drug adherence should be an important component of patient communication and specific interventions in PPCM.

Clinical and cardiovascular magnetic resonance profile of cardiomyopathy patients from South Africa: Pilot of the IMHOTEP study

BACKGROUND

Cardiomyopathy is an important cause of heart failure, however, there is notable lack of data on causes and manifestations of cardiomyopathy in Africa.

AIMS

The African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) aims to address the knowledge gap on etiology, treatment, and outcomes of cardiomyopathy in sub-Saharan Africa.

METHODS AND RESULTS

We conducted a single-center pilot study to delineate the clinical and cardiovascular magnetic resonance (CMR) phenotypes of cardiomyopathy in South African patients. Assessment of the first 99 adult incident cases [mean age 36.8 ± 12.5 years; females 53.5%] enrolled in IMHOTEP showed that dilated cardiomyopathy (n = 77) was commonest, followed by hypertrophic (n = 13), restrictive (n = 5) and arrhythmogenic (n = 4) cardiomyopathies. A broad range of etiologies were encountered with secondary causes identified in 42% of patients. Onset of symptoms in the peripartum period was observed in 47% of women, and peripartum cardiomyopathy was diagnosed in 32.1% of women recruited. In addition to electrocardiography and echocardiography, CMR was performed in 67 cases and contributed diagnostically in a third of cases. Acute inflammation was rarely observed [2%] on CMR, however, late gadolinium enhancement (LGE) was noted in 92% of cases.

CONCLUSION

We report a diverse spectrum of causes of cardiomyopathy in the South African population, with secondary, potentially treatable, etiologies in a significant proportion of cases. CMR was useful in delineating specific phenotypes and etiologies, influencing clinical care. A higher-than-expected burden of LGE was observed in this young patient cohort - the implications of which are yet to be determined.