some controversy still exists about the reality and mechanics of exercise-induced cardiac fatigue. Little is known about the kinetics of the impact of ultra-long duration exercise (ULDE) on the left ventricular (LV) function. We studied evolution of LV contractility indexes by serial examinations during a multistage ULDE race.

successive echocardiographic assessment was performed on 20 well-trained amateur male runners (42.8±3.5 year-old) participating in a 236km 5-stage foot race in the Sahara desert. An echocardiograhic study was performed the day before the race (T1), following the completion of the second (41km, T2) and the fifth (42.2km, T3) stages, then within the second day of recovery (T4). Contractility indexes included biplan ejection fraction (EF), LV global longitudinal (GL) peak-strain (PS) and strain-rate (SR), subendocardial layer (ENDO) and sub-epicardial layer (EPI) longitudinal strain. LV preload was evaluated by LV End Diastolic Biplan Volume (LVEDV) and afterload by LV Meridional Wall Stress.

no change of EF was observed during the study period.

LV GLPS significantly decreased at T2 (from – 20.8±2 to –19±2.9%, p<0.05) while GLSR did not change (from –1.19±0.17 to –1.19±0.17).

GLPS returned to initial values at T3 and T4; evolution of ENDO and EPI longitudinal PS strictly followed modifications of GLPS. Afterload did not change.

There was a tendancy to a transient drop in preload at T2 (111±20 to 104±16mL); preload then increased in T3 (115±25mL, p<0.05 versus T2) and T4 (121±20mL, p<0.05 versus T1 and T2).

transient drop in LV GLPS occured at early stage of the race but returned to pre-race value when exercise was repeated and remained stable 2 days after this race. Impact seemed to be of same magnitude in different layers of LV myocardium. Whether preload conditions influenced contractility indexes cannot be ruled out.