Comparison of cardiac magnetic resonance and speckle tracking echocardiography in cardiac evaluation of children with acute myocarditis with preserved left ventricular function.

This study aimed to evaluate the reliability and efficacy of speckle tracking echocardiography (STE) compared to cardiac magnetic resonance (CMR) in assessing left ventricular function and segmental involvement in patients with acute myocarditis and preserved left ventricular systolic function. We analyzed conventional echocardiography, two-dimensional STE, and CMR findings in 33 pediatric patients (aged 0-18 years) diagnosed with acute myocarditis. The STE results were compared with CMR findings. The mean patient age was 14.67 years (± 2.88), with 13 (39.4%) females and 20 (60.6%) males. The mean ejection fraction (EF) was 68.54% (± 6.54), and the mean fractional shortening (FS) was 38.20% (± 5.34). All patients had an EF greater than 55%, with no detected wall motion abnormalities. Mild pleural effusion was observed in 4 (12.1%) patients. A significantly reduced left ventricular global longitudinal strain (LV-GLS) pattern was detected in 45.4% (n = 15) of patients, with an average LV-GLS value of -18.12% (± 3.5). The LV-GLS reduction was uniformly distributed across all left ventricular segments (LV-GLSAP2: -18.1 ± 3.85, LV-GLSAP3: -17.33 ± 4.34, LV-GLSAP4: -18.88 ± 4.20). STE measurements showed a mean left ventricular end-diastolic volume of 71.54 ± 24.41 and an end-systolic volume of 37.62 ± 16.42, with a mean EF of 48.52 ± 9.39%. CMR identified widespread myocardial contrast enhancement in 25 (75.7%) patients. When comparing STE to CMR, using an LV-GLS cut-off value of -18%, the sensitivity and specificity for diagnosing myocarditis were 52% and 63%, respectively. Lowering the cut-off to -16% reduced sensitivity to 40% but increased specificity to 75%. No significant association was found between decreased LV-GLS values (<-18%) and late gadolinium enhancement on CMR or regional edema (p > 0.05). Our findings suggest that STE is a valuable diagnostic tool for detecting cardiac involvement, particularly in focal cases of pediatric acute myocarditis with normal EF. While CMR remains the gold standard, STE provides a practical, accessible alternative for monitoring disease progression in suspected myocarditis cases.