Cardiac arrhythmias occur in 3-40% of patients with acute myocarditis and cause significant morbidity and mortality. Myocardial injury also results in abnormal myocardial deformation. The relationship between left ventricular (LV) deformation, measured by two-dimensional speckle tracking echocardiography (2D-STE), and arrhythmia in pediatric myocarditis is unknown. We evaluated the association between 2D-STE and arrhythmias in children hospitalized with acute myocarditis. We reviewed patients ≤ 18 years hospitalized for acute myocarditis from 2008 to 2018. Arrhythmias were defined as 1) non-sustained or sustained ventricular tachycardia or ventricular fibrillation, 2) sustained supraventricular tachycardia (SVT), 3) high-grade or complete heart block, and 4) any arrhythmia treated with an antiarrhythmic medication. Systolic LV strain values (including LV global longitudinal strain (GLS), global circumferential strain (GCS), and six segments of LV regional long axis strain) were obtained from initial echocardiograms during hospitalization. Of 66 patients hospitalized, 23 (35%) had arrhythmias. SVT was the predominant arrhythmia (74%). Global and regional strain indices were reduced in the arrhythmia group: LV GLS [-8.9 (IQR -13.6, -6.1) vs. -13.7 (IQR -16.9, -9.7), p = 0.038]; basal inferior/septal [-10.7 (IQR -15.5, -7.8) vs. -16.4 (IQR -18, -11.8), p = 0.009]; basal anterior/lateral [-7.1 (IQR -12.8, -4.7) vs. -9.4 (IQR -16.7, -7.4), p = 0.025]; and mid inferior/septal segments [-9 (IQR -13, -7.7) vs. -14.1 (IQR -22.5, -10.7), p = 0.007]. After controlling for age, reductions in GLS and segmental strain in the two basal and two mid-segments were associated with increased arrhythmia occurrence (p <0.05). Our findings suggest that echocardiographic LV deformation by 2D-STE may be useful in identifying pediatric patients with acute myocarditis at risk for arrhythmias.
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