Left ventricular myocardial strain and strain rates in sub-endocardial and sub-epicardial layers before and after a marathon

Abstract

We assessed myocardial deformation in sub-endocardial and sub-epicardial layers of the left ventricle (LV) wall before and after running a marathon. Echocardiography scans were performed on 14 male, non-elite runners (mean ± SD; age 32 ± 10 years) who completed the 42.2-km London marathon. Para-sternal short axis and apical four-chamber views were recorded for off-line analysis. Peak longitudinal, radial and circumferential strains, peak systolic and early diastolic strain rates were recorded. Circumferential rotation in basal and apical LV scans was used to calculate torsion. Pre-race strain and strain rates were generally greater in the sub-endocardial layer of the LV wall. After race completion, a mixed pattern of change was observed with a reduction in sub-epicardial radial strain (32.6 ± 12.5 to 20.3 ± 9.6%; P < 0.01) and sub-endocardial circumferential strain (−26.9 ± 3.6 to −23.7 ± 4.1%; P < 0.01) at the apex. Rotation was not altered at either the apical or basal levels and thus torsion was not changed in either the sub-endocardium (6.72 ± 3.46° to 5.67 ± 4.98°) or the sub-epicardium (3.48 ± 2.68° to 3.01 ± 3.23°). Strain rates and rotation rates were only sporadically altered post-race. There are differences in deformation characteristics between the sub-endocardium and sub-epicardium at baseline, and the limited changes observed post-race were not specific to any region or depth of the LV wall.