Attila Oláh, Bálint András Barta, Alex Ali Sayour, Edina Urbán, Klára Alíz Stark,
Mihály Ruppert, Béla Merkely, Tamás Radovits
Heart and Vascular Center, Semmelweis University, Budapest
Introduction: Although regular exercise training is associated with cardiovascular benefits, cardiac remodeling induced by long-term, intense exercise training is also related to increased risk of arrhytmia.
Aims: We aimed at providing electrophysiologic investigation of exercise-induced myocardial hypertrophy in a rat model of athlete’s heart and determining sex-specific differences.
Method: Age-matched young adult rats were divided into female exercised (FEx), female control (FCo), male exercised (MEx) and male control (MCo) groups. After exercised animals completed a 12-week-long swim training protocol, echocardiography was used to confirm exercise-induced hypertrophy. In vivo electrophysiologic characterization was performed by programmed stimulation with an octapolar catheter inserted into the right atrium.
Results: Myocardial hypertrophy was verified by left ventricular mass (echocardiography) and post-mortem heart weight data in both exercised groups. We found signs of atrial remodeling in female exercised rats, increased P-wave duration and amplitude, as well as prolonged right atrial effective refractory period (RAERP 43.5±2.2ms FEx vs. 36.7±2.0ms FCo, p<0.05). We also observed increased T-wave amplitude and QT interval in female swim-trained rats. Hearts of male exercised rats were primarily associated with increased RR duration and Wenkebach cycle length (WCL 109.8±4.7ms MEx vs. 97.3±2.1ms MCo, p<0.05) compared to control ones. Exercise training was related to increased R wave amplitude and QRS duration in both genders and we could induce non-sustianed atrial fluttern in two exercised animals by double extrastimulation.
Conclusion: Our data suggests that exercise-induced cardiac hypertrophy might hold an increased risk of arrhytmia. In male individuals elevated parasympathetic tone, while in female ones marks of atrial remodeling could be the characteristic alterations.
ÚNKP-17-4-I-SE-78 to Attila Oláh, MD, PhD
E-mail address: firstname.lastname@example.org
Poster presentation preferred