(14, 26).
Additionally, the sub-endocardial layers of the myocardium with a predominance of longitudinal myocardial fibers are typically impacted in myocarditis. Hence the longitudinal left ventricular contractile function is expected to be most impaired in acute myocarditis (27, 28). These are consistent with results from the study which demonstrated the endo-GLS to be more impaired compared to mid- and epicardial-GLS(29). The distribution of LV-GLS impairment in studies examining regional systolic dysfunction which match areas of inflammatory response further strengthens the value of measuring LV-GLS in the clinical setting.
Whilst the majority of the included studies included patients with acute inflammatory myocarditis, one study included patients with immune checkpoint inhibitor (ICI) myocarditis(14), an entity that is more complex and multi-faceted than inflammatory myocarditis, despite similar diagnostic criteria (30).Patients with ICI myocarditis may possibly have a greater impairment in LV-GLS and LV systolic function compared to other subtypes, particularly with the presence of confounding factors such as para-neoplastic cytokines, and other mechanisms of treatment mediated toxicity