Introduction: Myocarditis may be difficult to diagnose because of the variety of its clinical manifestations, and the clinical course of the disease can be unpredictable. Nevertheless, some patients may exhibit partial or full contractile recovery following myocarditis. Standard and speckle-tracking echocardiography may serve as tools to follow this recovery.
Objectives: We aimed to evaluate predictors of positive left ventricular (LV) remodeling after active myocarditis (AM).
Patients and methods: A database of a high‑volume, tertiary cardiology center was searched for patients with AM hospitalized between 2016 and 2019. They were included in the analysis based on clinical manifestations and presence of at least 1 of the following diagnostic criteria: positive findings on electrocardiography / Holter monitoring, echocardiography, elevated troponin T/I levels, functional or structural abnormalities on cardiac imaging, or tissue characterization by cardiac magnetic resonance. LV global longitudinal strain and mechanical dispersion (MD; defined as SD of the time to peak longitudinal strain derived from all LV segments in 3 apical views) were determined. Echocardiographic response (positive LV remodeling measured by transthoracic echocardiography) was defined as end‑systolic volume (ESV) reduction by 15% or greater or end-diastolic volume (EDV) reduction by 15% or greater from the baseline values.
Results: A total of 61 consecutive patients were recruited. The median follow‑up was 1.4 years (range, 0.3-4). The mortality rate was 1.6%. Echocardiographic response was noted in 24 patients (39.4%). A multivariable Cox regression model including significant baseline differences as covariates showed that QRS duration (hazard ratio [HR], 1.31; 95% CI, 1.17-1.57; P = 0.049), MD (HR, 1.03; 95% CI, 1.01-1.07; P = 0.04), and mineralocorticoid receptor antagonist [MRA] use (HR, 8.60; 95% CI, 1.50-46.49; P = 0.01) were independently associated with positive LV remodeling with ESV reduction. MD (HR, 1.04; 95% CI, 1.02-1.06; P = 0.04) was also independently associated with positive LV remodeling with EDV reduction.
Conclusions: Mechanical dispersion, QRS duration, and MRA use are independent predictors of positive LV remodeling in individuals with a history of AM.