The Diagnostic Role of Echocardiographic Strain Analysis in Patients Presenting with Chest Pain and Elevated Troponin: A Multicenter Study

Background: Myocarditis presenting as acute chest pain with elevated troponins without significant cardiac compromise is rare in previously healthy children, often referred to as myopericarditis. Diagnosis is challenging, as conventional echocardiographic measures of systolic function can be normal. The aim of this study was to demonstrate the diagnostic utility of strain imaging in this scenario. Methods: This was a multicenter, retrospective study including patients presenting with chest pain and elevated troponin from 10 institutions who underwent cardiac magnetic resonance imaging and transthoracic echocardiography within 30 days of each other (group 1). Findings were compared with those among 19 control subjects (group 2). Clinical data and conventional echocardiographic and cardiac magnetic resonance imaging data were collected. Echocardiography-derived strain was measured at the core laboratory. Group 1 was divided into subgroups as myocarditis positive (group 1a) or negative (group 1b) on cardiac magnetic resonance imaging on the basis of established criteria. Results: Group 1 included 108 subjects (88 in group 1a, 20 in group 1b). Although all groups had normal mean fractional shortening and mean left ventricular ejection fraction, group 1 had significantly lower ejection fraction (56.8 ± 7.0%) compared with group 2 (62.3 ± 4.9%; P <.005) and fractional shortening (31.2 ± 4.9%) compared with group 2 (34.1 ± 3.5%; P <.05). Additionally, peak global longitudinal strain (GLS) was markedly abnormal in group 1 (−13.9 ± 3.4%) compared with group 2 (−19.8 ± 2.1%; P <.001). In subgroup analysis, GLS was markedly abnormal in group 1a (−13.2 ± 3.0%) compared with group 1b (−17.3 ± 2.6%; P <.001). Fifty-four subjects underwent follow-up echocardiography (46 in group 1a, eight in group 1b), with mean a follow-up time of 10 ± 11 months. At follow-up, whereas ejection fraction and fractional shortening returned to normal in all patients, abnormalities in strain persisted in group 1, with 22% still having abnormal GLS. Moreover, mean GLS was more abnormal in group 1a (−16.1 ± 2.6%) compared with group 1b (−17.4 ± 1.2%; P <.05). Conclusions: The present study demonstrates that echocardiographic GLS is significantly worse in subjects with myopericarditis presenting with chest pain and elevated troponins compared with control subjects even when conventional measures of systolic function are largely normal and that these abnormalities persisted over time.