Background: Acute myocarditis remains a challenging clinical diagnosis with limited epidemiological data and poorly defined markers of adverse risk. We sought to build a better understanding of myocarditis epidemiology and to integrate clinical, genetic and advanced imaging data to generate new insights into myocarditis pathobiology. Methods and Results: (1) Evaluation of population-level hospital admission data from NHS England from 1998-2017 revealed a rising incidence of myocarditis, at least two-fold greater than that reported from pathological registries, most commonly amongst men with median age 36 years and women aged 46 years, with distinct peaks over Winter and the greatest burden in London. (2) Cardiovascular magnetic resonance (CMR) phenotype study of a 114 prospectively recruited patients with acute myocarditis demonstrated the natural history of changes in left ventricular parameters over 12 months and revealed a correlation between change in myocardial mechanics, specifically circumferential strain, and extent of myocardial oedema by T2 mapping (R=-0.70, p=0.01). (3) Genetic sequencing of 231 unrelated patients recruited with acute myocarditis revealed the presence of truncating variants in key cardiomyopathy genes in 4.8% of the cohort, particularly linked to arrhythmogenic ventricular cardiomyopathy (AVC) with significant enrichment compared with 1054 healthy volunteers indicating a potential overlap between myocarditis and AVC (odds ratio 8.2; 95% CI 2.4-28.3; p=0.001). (4) Retrospective long-term clinical outcome study of 401 patients with mid-wall/subepicardial late gadolinium enhancement (LGE) but otherwise normal LV volumes and function suggestive of healed myocarditis demonstrated a low risk of actual or aborted sudden cardiac death over a median follow-up of 4.3 years (incidence rate per 100 patient-years of 0.05%). (5) Psychological study of post-traumatic stress disorder amongst 231 patients with acute myocarditis compared with 44 patients with acute myocardial infarction highlighted the profound and long-lasting psychological morbidity associated uniquely with myocarditis. Conclusion: Myocarditis is a heterogeneous disease that remains vastly underestimated in prevalence. Integration of advanced CMR techniques with genomic data may provide incremental value in early diagnosis, non-invasive surveillance and identification of high-risk individuals who may benefit from a more personalised approach with close monitoring and targeted therapy.