Abstract
Acute myocarditis is a severe disease with a high mortality rate and various dynamic changes visible on electrocardiograms (ECGs). The purpose of the present study was to investigate ECG findings of patients with acute myocarditis, ECG findings associated with fulminant myocarditis (FM) and the characteristics of ST elevation on admission. A retrospective analysis of 1,814 ECGs of 274 consecutive patients with acute myocarditis aged ≥13 years, who were hospitalized in two centres between August 2007 and November 2019, was performed. A total of 251 patients with myocarditis (91.6%) presented with ECG abnormalities. The most common ECG findings were T-wave inversion and ST elevation. Univariate logistic regression analysis demonstrated that 12 ECG findings were associated with FM. Multivariate regression analysis revealed that the independent predictive factors for FM included ventricular tachycardia, high-degree atrioventricular block, sinus tachycardia, low voltage and QRS duration of ≥120 msec (all P<0.05). A total of 112 cases displayed ST elevation at admission. Of these, ST elevation without T-wave inversion (n=87) was associated with a shorter duration of cardiac symptoms (1.5 vs. 3.1 days; P<0.001) compared with ST elevation with T-wave inversion (n=25). Of the aforementioned 87 patients, 71 (81.6%) presented with T-wave inversion at the hospital. The median time from the onset of cardiac symptoms to T-wave inversion was 4.0 days. In conclusion, patients with acute myocarditis exhibited various dynamic changes on ECG. Thus, ECGs should be widely used for the assessment of severity and the characteristics of ST elevation on admission.