CARDIAC FUNCTION BY STRAIN IMAGING: KEY TO THE INCREASED PERFORMANCE CAPACITIES OF ENDURANCE‐TRAINED ATHLETES

Abstract

Background: To increase the performance capacity of a triathlete (Tri), a variety of adaptations are necessary. The heart is the central and the most important limiting factor. The structural heart adaptations in Tri have important repercussion on cardiac function. The left ventricular diastole shows specific characteristics that determine performance capacity. Methods: 40 male Tri were compared with 31 active male controls and with 112 patients with ischemic heart disease. All subjects underwent tissue Doppler and strain imaging. Results: The late diastolic filling period in Tri has specific characteristics. Tissue imaging demonstrated in Tri specific characteristics of both the late passive diastolic filling period and the early active diastolic relaxation period. The significant differences between the three groups concerning the strain values at the basal and the mid septum in the longitudinal axis by aortic valve closure and by mitral valve opening were extremely striking. The values of the end‐diastolic strain by the end of the a‐wave: negative in Tri, near‐zero in normal controls, and marked positive in coronary patients were fascinating (fig. 1). Conclusions: The marked negative end‐diastolic strain in Tri can be explained by an increased muscular tone after a rapid and almost complete early diastolic filling of the left ventricle. This increased muscular tone is caused by an increase in the sarcomere length and by an increase in the number of actin‐myosin cross‐bridge interactions. These specific systolic and especially supernormal diastolic properties of the left ventricle with an increased diastolic reserve, enhance the aerobic capacities, resulting in an increased performance capacity.