Epidemiology Characteristics and Outcome of Patients With Clinically Diagnosed Acute Myocarditis

Abstract

Background: There are controversial data regarding the outcome and management of patients hospitalized with clinically diagnosed acute myocarditis.

Methods: We 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.

Results: The 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).

Conclusions: Patients 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.

Keywords: Acute myocarditis; In-hospital outcome; Prognosis.