PhD Scientific Days 2018

Budapest, April 19–20, 2018

Electrophysiologic investigation of exercise-induced cardiac hypertrophy in a rodent model of athlete’s heart

Oláh, Attila

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

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Text of the abstract

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.

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ÚNKP-17-4-I-SE-78 to Attila Oláh, MD, PhD
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