525 PROGNOSTIC RELEVANCE OF DEMOGRAPHIC FACTORS IN CARDIAC MAGNETIC RESONANCE-PROVEN ACUTE MYOCARDITIS. A COHORT STUDY

Abstract

Abstract Aims Acute myocarditis (AM) is a heterogeneous condition with variable estimates of survival. Contemporary criteria for the diagnosis of clinically suspected AM enable non-invasive assessment, resulting in greater sensitivity and more representative cohorts. We aimed to describe the demographic characteristics and long-term outcomes of patients with AM diagnosed using non-invasive criteria. Methods and Results A total of 199 patients with cardiac magnetic resonance (CMR)-confirmed AM were included. The majority (n=130, 65%) were male and the average age was 39±16 years. Half of patients were White (n=99, 52%) with the remainder from Black and Minority Ethnic (BAME) groups. The most common clinical presentation was with chest pain (n=156, 78%), with smaller numbers presenting with breathlessness (n=25, 13%) and arrhythmias (n=18, 9%). Patients admitted with breathlessness were sicker and more often required inotropes, steroids, and renal replacement therapy (p<0.001, p<0.001, and p=0.01, respectively). Over a median follow-up of 53 (IQR 34–76) months, 11 patients (6%) experienced an adverse outcome, defined as a composite of all-cause mortality, resuscitated cardiac arrest, and appropriate implantable cardioverter defibrillator (ICD) therapy. Patients in the arrhythmia group had a worse prognosis, with a nearly 7-fold risk of adverse events (hazard ratio [HR] 6.97; 95% Confidence Interval [CI] 1.87–26.00, p=0.004). Sex and ethnicity were not significantly associated with the outcome. Conclusions AM is highly heterogeneous with an overall favourable prognosis. Three quarters of patients with AM present with chest pain and this is associated with a benign prognosis. AM presenting with life-threatening arrhythmias is associated with higher risk of adverse events.