Contemporary study of acute myocarditis in South Africa: CAMISA.

Aims: This study aims to determine the clinical presentations, aetiologies and outcomes of patients presenting with acute myocarditis (AM) in South Africa.

Methods: This is a prospective cohort study. Consecutive patients presenting to Tygerberg Hospital, Cape Town, South Africa, between August 2017 and November 2021 who fulfilled the European Society of Cardiology diagnostic criteria for clinically suspected myocarditis undergoing all recommended investigations, including cardiac MRI (CMR) and endomyocardial biopsy (EMB), were included.

Results: 111 cases (mean age 41.2 years, 66.3% male) of clinically suspected myocarditis were recruited. AM was confirmed in 89: 44 (49.4%) on CMR only, 16 (18.0%) on EMB only and 29 (32.6%) on both CMR and EMB. 46 (51.7%) presented with infarct-like symptoms, 31 (34.8%) presented with heart failure (HF), 8 (9.0%) with sustained ventricular tachycardia (VT) and 4 (4.5%) with complete heart block (CHB). Viral pathogens were detected in 52 (58.4%) patients with AM, with Parvovirus B19 the most frequent in 39 (75.0%) as monoinfection and as coinfection in 4 (3 (5.8%) with Epstein-Barr virus (EBV) and 1 (1.9%) with EBV and human herpesvirus 6. The prespecified adverse outcome, defined as the occurrence of major adverse clinical events, including cardiac death, documented sustained VT, recurrence of AM and HF hospitalisation, occurred in 30.3%. Initial presentation with sustained VT (HR 5.36, 95% CI 1.76 to 16.33, p=0.003) or CHB (HR 5.67, 95% CI 1.38 to 23.26, p=0.016) was a significant predictor of adverse outcome on multivariate analysis.

Conclusion: We report data from the largest cohort of patients with AM outside of the developed world. It provides insight into the clinical presentation, aetiology, viral pathogens and outcomes of patients with AM locally. The findings in this cohort from Africa appear similar to the developed world.