Epidemiology Characteristics and Outcome of Patients With Clinically Diagnosed Acute Myocarditis

Abstract

BACKGROUNDThere are controversial data regarding the outcome and management of patients hospitalized with clinically diagnosed acute myocarditis. METHODSWe retrospectively evaluated data of 322 consecutive patients admitted to the Sheba Medical Center with clinically suspected acute myocarditis from January 2005 to December 2017. Patients were subdivided into 2 groups based on their left ventricular ejection fraction (LVEF) at presentation: 1) patients with an LVEF <50% (n = 60) and 2) patients with an LVEF ≥50% (n = 260). We aimed to evaluate the clinical characteristics, management, and in-hospital outcome as well as short-term and 1-year outcome of patients admitted with acute myocarditis. RESULTSThe mean age of the study population was 37 ± 14 years, most of them (84%) males. Although chest pain was the main complaint in 89% of the patients at presentation, only 35% had typical pericardial pain. Patients with a LVEF <50% were more likely to demonstrate ST depression or T wave inversion on their electrocardiogram (ECG) at presentation (33% vs 18%, P = 0.007), and have higher levels of admission and peak troponin compared to those with LVEF ≥50%,(12.7 μ/L ± 15 µ/L vs 5.5 μ/L ± 9.2 μ/L, P = 0.001 for admission troponin, 18.8 μ/L ± 19.9 μ/L vs 8.4 μ/L ± 11.6 μ/L, P <0.001, for peak troponin). Univariate analysis showed that patients with an LVEF <50% were more likely to suffer from adverse cardiovascular events, defined as a composite of the following: 1) acute decompensated congestive heart failure; 2) ventricular arrhythmias; and 3) in-hospital mortality, compared to those with an LVEF ≥50% (15 [25%] vs10 [4%], P <0.001). Consistently, multivariable analysis showed that patients with an LVEF <50% had a 4-fold increased risk of adverse cardiovascular events compared to those patients with an LVEF ≥50% (heart rate [HR] = 4.30; 95% confidence interval [CI] 1.59-11.49; P <0.001). CONCLUSIONSPatients with clinical acute myocarditis seem to have an overall good prognosis. Although patients with an LVEF <50% are at a higher risk of in-hospital adverse events compared to those with an LVEF ≥50%, this propensity is not reflected during 1-year of follow-up.