Longitudinal, Radial and Circumferential 2-D Cardiac Strain Imaging in Healthy Subjects Following a Marathon

Abstract

Previous work has demonstrated changes in left ventricular (LV) diastolic function following marathon running. PURPOSE: Longitudinal, radial and circumferential 2-D strain rate imaging of the LV provides an additional tool to examine alterations in ventricular function observed following marathon running. METHODS: Fourteen subjects (Mean ± SD, age 34.4 ± 7.1 years, Height 176.8 ± 6.8 cm, Body mass 78.0 ± 8.2 kg) were echocardiographically assessed pre, and immediately post completion of the London Marathon 2005. All echocardiographic images were acquired using an ultrasound system (Vivid 7, GE Vingmed, Horten, Norway) and analysed offline using dedicated 2d Strain software (echopac, GE Vingmed, Horten, Norway). An apical window was used to assess longitudinal function and a parasternal short axis view just below mitral valve level to assess cirumferential and radial function. Strain rate values were measured from septal, lateral, inferior, anterior and posterior segments of the LV in systole and early diastole. Mean data were averaged over these sites. Pre to post race changes were analyzed by repeated measure ANOVA. RESULTS: Peak systolic strain rate in the circumferential and radial planes was significantly greater post race (1.07 ± 0.17 vs. 1.21 ± 0.18, and 1.22 ± 0.15 vs. 1.48 ± 0.34 l/s respectively, P<0.05). A downward trend in the diastolic strain rate in both the circumferential and radial planes was observed, although this was not statistically significant (1.27 ± 0.30 vs. 1.17 ± 0.43, and 1.27 ± 0.28 vs. 1.22 ± 0.63 l/s respectively). Technical issues hindered the assessment of strain rate in the longitudinal plane (resulting in an n of 6), mean peak systolic strain rate was elevated post exercise (0.73 ± 0.15 vs. 0.96 ± 0.18) although not significantly, whilst there was no change in diastolic strain rate (1.03 ± 0.32 vs. 1.03 ± 0.14). CONCLUSION: 2-D strain imaging data in the radial and circumferential planes suggests that systolic function is enhanced following a marathon. The current data do not fully support the depression in diastolic function reported in previous marathon studies employing conventional echocardiographic techniques, despite a downward trend. Further work is required to examine the influence of prolonged exercise on longitudinal systolic and diastolic strain imaging.