Transient Right but Not Left Ventricular Dysfunction After Strenuous Exercise at High Altitude

OBJECTIVES: We sought to evaluate whether prolonged exercise in ultramarathon runners results in left ventricular (LV) damage. BACKGROUND: Strenuous exercise has been reported to cause LV damage. METHODS: Fourteen runners who completed an ultramarathon at high altitude underwent echocardiography, finger-tip oximetry and blood measurements of cardiac troponin I (cTnI) and creatine kinase, MB fraction (CK-MB) levels before, immediately after and 1 day after the race. RESULTS: At baseline, the echocardiograms showed normal LV and right ventricular (RV) size and function in all subjects, as well as mild tricuspid regurgitation in nine subjects, with normal estimated pulmonary artery systolic pressure (mean 28 mm Hg). At baseline, all oxymetric readings and CK-MB measurements were normal, and cTnI was undetectable. Immediately after the race, the echocardiograms showed the expected augmentation of global and segmental LV function in all subjects. Although the RV was normal in nine subjects, five developed marked RV dilation and hypokinesia, paradoxic septal motion, pulmonary hypertension and wheezing. CK-MB values were elevated in all subjects. In all but one subject cTnI was undetectable. In that subject there was a small elevation in cTnI accompanied by severe RV dysfunction and pulmonary hypertension. At the 1-day follow-up study, the echocardiographic measurements had normalized in all subjects. CONCLUSIONS: In trained athletes, strenuous exercise at high altitude did not result in LV damage. However, wheezing, reversible pulmonary hypertension and RV dysfunction occurred in a third of those completing the race. The incidence and pathogenesis of these findings remain to be determined.