Evaluation of myocardial performance by serial speckle tracking echocardiography in diagnosis and follow-up of a patient with eosinophilic myocarditis.

Background: Speckle tracking echocardiography (STE) has been used as an adjunct diagnostic modality in patients with eosinophilic myocarditis. Its serial dynamic nature, however, has never been reported before.

Case presentation: A 17-year-old boy presented in cardiogenic shock state. His full blood count revealed an absolute eosinophilic count of 11.18 × 10³/μL. An emergency 2D echocardiogram (2DE) showed global left ventricular hypokinesia with LVEF = 9.0% by Simpson's method and a large amount of pericardial effusion. STE showed a global longitudinal strain (GLS) of - 4.1%. Because of his poor clinical status and presence of marked hypereosinophilia and the possibility of eosinophilic myocarditis (EM), parenteral pulse therapy with methylprednisolone and inotropes was started with subsequent improvement within the next 48 h. Over the next few days, he had his first cardiovascular magnetic resonance imaging (CMR), which showed late gadolinium enhancement (LGE) in different cardiac regions. After two weeks of therapy, he left the hospital in a stable condition, with LVEF = 38.0%, and GLS = - 13.9%. He did well during his two months of outpatient follow-ups and was found to have an absolute eosinophil count of 0.0% on several occasions. Unfortunately, he was re-admitted because of treatment non-compliance with almost the same, albeit milder, symptoms. The WBC count was 18.1 × 10³ per microliter, and the eosinophilic count was 5.04 × 10³/μL (28%). Heart failure treatment and high-dose prednisolone were started. After 15 days of admission, he got better and was discharged. During both hospital admissions and several months of follow-up, he had multiple 2DEs, STE, and two CMR studies. None of his STEs were identical to the prior studies and were dynamic with frequent wax and wanes throughout the admissions and follow-ups. Thus a single admission-time STE study was not sufficient enough to properly predict the patient's outcome. Follow-up STEs showed new sites of myocardial involvement despite the absence of eosinophilia.

Conclusion: The use of STE in this patient, proved to have an added value in the evaluation and stratification of the left ventricular function in patients with EM and can be used as a diagnostic adjunct to CMR for diagnosis of EM.