Tamás Radovits, Attila Oláh, Attila Kovács, Árpád Lux, Szilveszter Braun, Bálint Károly Lakatos, Mihály Ruppert, Alex Ali Sayour, Bálint András Barta, Béla Merkely
Heart and Vascular Center, Semmelweis University, Budapest, Hungary
Introduction Although exercise-induced cardiac hypertrophy has been investigated intensively recently, consecutive evaluation of its development and regression dynamics is not fully described.
Aims In the current study we aimed to characterize the effects of regular exercise training and detraining on myocardial mechanics by speckle-tracking echocardiography (STE) in a rat model.
Methods Rats were divided into exercised (n=12) and control (n=12) groups. Trained rats swam 200min/day for 12 weeks. After completion of the training protocol, rats remained sedentary for 8 weeks (detraining period). Echocardiographic follow-up was performed regularly using a 13MHz linear transducer to obtain LV long- and short-axis recordings for STE analysis. Global longitudinal and circumferential strain and systolic strain rate (CSr, LSr) were measured. LV pressure-volume analysis was performed using also additional groups to obtain hemodynamic data.
Results Echocardiographic examinations showed the development of LV hypertrophy in the exercised group (exercised vs. control; LV mass index: 2.4±0.1 vs 2.0±0.1g/kg, p<0.05), which was followed by improvement of systolic function. These differences disappeared during detraining (2.3±0.1 vs 2.4±0.1g/kg, n.s.). Strain and strain rate values were all increased after the training period (exercised vs. control; CSr:−5.6±0.3 vs −4.0±0.31/s; LSr: −4.6±0.2 vs −3.9±0.21/s, p<0.05), whereas supernormal values rapidly reversed to the control level after training cessation. Load-independent hemodynamic indices, e.g. preload recruitable stroke work, confirmed the exercise-induced systolic improvement and complete regression after detraining.
Conclusion Our results would serve as the first comprehensive data to describe the development and regression dynamics of morphological and functional aspects of physiological myocardial hypertrophy in detail. Speckle-tracking echocardiography has been proved to be feasible to follow-up changes induced by exercise training and detraining and might provide an early possibility to distinct between physiological and pathological conditions.
Supported by the ÚNKP-17-4 New National Excellence Program of the Ministry of Human Capacities to T.R.
Submitted to the ÚNKP-conference. Tamás Radovits is an ÚNKP-17-4 scholarship holder (postdoctoral category).