Electrocardiographic Predictors of Morbidity and Mortality in Patients With Acute Myocarditis: The Importance of QRS-T Angle.

Background: Acute myocarditis carries a variable prognosis. We evaluated the morbidity and mortality rates in patients with acute myocarditis and admission electrocardiographic predictors of outcome.

Methods And Results: Patients admitted to a tertiary hospital with a clinical diagnosis of acute myocarditis were evaluated; 193 patients were included. Median follow-up was 5.7 years, 82% were male, and overal median age was 30 years (range 21-39). The most common clinical presentations were chest pain (77%) and fever (53%). The 30-day survival rate was 98.9%. Overall survival during follow-up was 94.3%. The most common abnormalities observed on electrocardiography were T-wave changes (36%) and ST-segment changes (32%). Less frequent changes included abnormal T-wave axis (>105° or < -15°; 16%), abnormal QRS axis (12%), QTc >460 ms (11%), and QRS interval ≥120 ms (5%). Wide QRS-T angle (≥100°) was demonstrated in 13% of the patients and was associated with an increased mortality rate compared with patients with a narrow QRS-T angle (20% vs 4%; P = .007). The rate of heart failure among patients with a wide QRS-T angle was significantly higher (36% vs 10%; P = .001). Cox regression analysis demonstrated that a wide QRS-T angle (≥100°) was a significant independent predictor of heart failure (hazard ratio [HR] 3.20, 95% confidence interval [CI] 1.35-7.59; P < .01) and of the combined end point of death or heart failure (HR 2.56, 95% CI 1.14-5.75; P < .05).

Conclusions: QRS-T angle is a predictor of increased morbidity and mortality in acute myocarditis.