ORIGINAL INVESTIGATION Biventricular Response of the Heart to Endurance Exercise Training in Previously Untrained Subjects Aleksandra Rojek, M.D., Dariusz Bialy, M.D., Ph.D., Monika Przewlocka-Kosmala, M.D., Ph.D., Marta Negrusz-Kawecka, M.D., Ph.D., Andrzej Mysiak, M.D., Ph.D., and Wojciech Kosmala, M.D., Ph.D. Cardiology Department, Medical University, Wroclaw, Poland Background: Functional adaptation of the heart to regular strenuous exercise has not been fully eluci- dated yet, with different patterns of alterations being reported. We evaluated the effect of endurance exercise training (EET) on left (LV) and right ventricular (RV) mechanics in amateur individuals preparing for triathlon competitions. Methods: Twenty-one subjects aged 33  6 years underwent conventional and speckle tracking echocardiography at rest before and after a high-intensity (12.3  1.0 h/week) 12-month EET. Results: At follow-up, in addition to the improvement in LV diastolic parameters, a sig- nificant decrease in longitudinal (26.0  3.3% vs. 24.3  3.2%, P < 0.04), circumferential (24.3  4.3% vs. 20.1  3.8%, P < 0.002), and radial strains (46.8  18.3% vs. 37.8  12.9%, P < 0.03), and rotation (9.7  4.8% vs. 7.1  4.0 deg, P < 0.04) was demonstrated at the apex, whereas the LV base was found to show an increase in rotation (3.9  2.8% vs. 5.9  1.8 deg, P < 0.01). Overall hemo- dynamic effectiveness of the LV was preserved, as evidenced by the unchanged ejection fraction, car- diac output, twist, and torsion. RV systolic function as assessed by strain was significantly reduced with EET (28.1  6.7% vs. 23.7  8.6%, P < 0.03). Conclusions: EET modifies both LV and RV performance at rest in previously untrained subjects. The true nature of these changes (adaptive or maladaptive) is unclear, but the hypothesis of different responses of the LV apex and base, with the reduction in con- tractility of the former and increase in rotation of the latter, representing a protective mechanism that reduces myocardial stress might be considered. (Echocardiography 2014;00:1–8) Key words: endurance exercise training, echocardiography, left ventricular function, right ventricular function Endurance exercise training (EET) leads to numerous alterations in cardiac morphology and function, representing an adaptive response to a recurring increase in hemodynamic loading. 1,2 These changes are thought to be not only simple consequences of altered hemodynamic condi- tions but may also serve as mechanisms that assist in optimizing cardiac performance. While the typical pattern of structural remodeling, including a slight left ventricular (LV) and right ventricular (RV) dilatation and myocardial wall thickening, has been well characterized, 3,4 car- diac functional adaptations to intense training have not been entirely clarified. Conventional echocardiographic evaluation of LV systolic function, including commonly assessed measures—e.g., ejection fraction and fractional shortening—did not show significant differences between athletes and nonathletes. 5,6 Implementation of novel echocardiographic modal- ities, such as tissue Doppler and speckle tracking imaging, has extended diagnostic opportunities to unravel functional alterations in the athlete’s heart. Specifically, the speckle tracking imaging technique allows for the complex assessment of different aspects of cardiac mechanics, including myocardial strains and LV rotation, and has suffi- cient sensitivity to detect even minor changes in functional parameters. 7 Previous investigations evaluating the effects of regular exercise on the function of the heart were carried out mainly in groups of competitive athletes, frequently on the basis of comparisons with sedentary individuals, and reported incoher- ent results. 8–10 In the available literature, there is a scarcity of analogous data concerning initially untrained subjects. 11,12 In this study, we sought to investigate the effect of EET on LV and RV function in ama- teur individuals preparing for triathlon compe- titions. Address for correspondence and reprint requests: Wojciech Kosmala, M.D., Ph.D., Cardiology Department, Wroclaw Medical University, ul. Borowska 213/1.13, 50-556 Wroclaw, Poland. Fax: 0048717364209; E-mail: wojciech.kosmala@umed.wroc.pl 1 © 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12737 Echocardiography