Purpose: Data derived by cardiac magnetic resonance (CMR) feature tracking suggest that not only left ventricular but also left atrial function is impaired in patients with acute myocarditis. Therefore, we investigated the diagnostic value of speckle tracking echocardiography of the left ventricle and left atrium in patients with acute myocarditis and normal left ventricular ejection fraction (LVEF). Methods and results: 30 patients with acute myocarditis confirmed by CMR according to the Lake Louise criteria and 20 healthy controls were analyzed including global longitudinal strain (GLS) and left atrial (LA) strain parameters. Although preserved LVEF was present in both groups, GLS was significantly lower in patients with acute myocarditis (GLS - 19.1 +/- 1.8% vs. GLS - 22.1 +/- 1.7%, p < 0.001). Further diastolic dysfunction measured by E/e' mean was significantly deteriorated in the myocarditis group compared to the control group (E/e' mean 6.4 +/- 1.6 vs. 5.5 +/- 1.0, p = 0.038). LA reservoir function (47.6 +/- 10.4% vs. 55.5 +/- 10.8%, p = 0.013) and LA conduit function (-33.0 +/- 9.6% vs. -39.4 +/- 9.5%, p = 0.024) were significantly reduced in patients with acute myocarditis compared to healthy controls. Also left atrial stiffness index (0.15 +/- 0.05 vs. 0.10 +/- 0.03, p = 0.003) as well as left atrial filling index (1.67 +/- 0.47 vs. 1.29 +/- 0.34, p = 0.004) were deteriorated in patients with myocarditis compared to the control group. Conclusion: In patients with acute myocarditis and preserved LVEF not only GLS but also LA reservoir function, LA conduit function and left atrial stiffness index as well as left atrial filling index were impaired compared to healthy controls indicating ventricular diastolic dysfunction and elevated LV filling pressures.