Acute coronary syndrome versus acute myocarditis in young adults-value of speckle tracking echocardiography

Abstract

Purpose: Comparing myocarditis with an acute coronary syndrome (ACS)-like presentation and acute myocardial infarction (AMI) poses an important clinical challenge. The purpose of the study was to investigate the diagnostic value of the clinical, laboratory and especially echocardiographic characteristics including speckle tracking echocardiography (STE) of patients with ACS-like myocarditis and AMI.

Methods: We conducted a retrospective analysis comparing 69 symptomatic patients (≤ 45 years old), hospitalized at the Department of Interventional Cardiology (Medical University of Lodz, Poland) between April 2014 and June 2021 with an initial diagnosis of ST-segment elevation myocardial infarction.

Results: 37 patients with the cardiac magnetic resonance-confirmed acute myocarditis and 32 patients diagnosed with AMI based on the clinical presentation, electrocardiogram and the presence of a culprit lesion on the coronary angiography were analysed including echocardiography parameters. On STE analysis an average global longitudinal (GLS), radial and circumferential strain including three-layers observation were significantly lower (absolute value) in patients with AMI versus acute myocarditis (p<0.05). There was no significant difference in Endo/Epi ratio (p = 0.144) between the groups. An average GLS < (-17.5) represented the optimal cut-off value for the myocarditis diagnosis.

Conclusion: In patients with AMI a significant reduction of global and three-layers strains compared to patients with myocarditis was detected. Furthermore, our analysis also confirmed the discriminative pattern of myocardial injury between the groups.

Fig 1. Layer–specific circumferential strain (Endo/Epi ratio) in the myocarditis and MI groups.

Data are shown as Tukey boxplot and raw data, taking into account normal references values for age, p = 0.144.

Fig 2

(a) ROC curve of the GLS average [%] for the diagnosis of clinically suspected myocarditis. The AUC was 0.737 (standard error = 0.061, 95% confidence interval 0.795–0.954). It shows that the sensitivity and specificity of the GLS is adequate in statistics (b) Global longitudinal strain [%] in the myocarditis and MI groups including normal reference of strain. Data are shown as Tukey boxplot, (p = 0.000).

Fig 3

Scatter plot of a strong correlation between GLS average [%] and left ventricular ejection fraction [%] in whole population (a), myocarditis group (b) and myocardial infarction group (c).

Fig 4

Example of the longitudinal strain bull’s eye plot derived from two-dimensional speckle tracking imaging in patients admitted with an initial diagnosis of anterolateral STEMI and with the final diagnosis of myocardial infarction resulted from occlusion of the left anterior descending artery (a) and acute myocarditis (b).

Fig 5. Global circumferential strain (average) [%] concerning normal reference values.

Tukey boxplot (mean ± SD).

Fig 6. Global circumferential endocardial and epicardial strain in the myocarditis and MI groups.

Data are shown as Tukey boxplots, taking into account normal reference values for age, p<0.05 (a) Endocardial GCS [%]. (b) Epicardial GCS [%].