Stein Ricardo, Medeiros Claudio M, Rosito Guido A, Zimerman Leandro I, Ribeiro Jorge P
Cardiology Division, Hospital de Clínicas de Porto Alegre, and Department of Medicine, Faculty of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
J Am Coll Cardiol. 2002 Mar 20;39(6):1033-8. doi: 10.1016/s0735-1097(02)01722-9.
In the present study, we evaluated sinus and atrioventricular (AV) node electrophysiology of endurance athletes and untrained individuals before and after autonomic pharmacologic blockade.
Endurance athletes present a higher prevalence of sinus bradycardia and AV conduction abnormalities, as compared with untrained individuals. Previous data from our laboratory suggest that nonautonomic factors may be responsible for the longer AV node refractory period found in well-trained athletes.
Six aerobically trained male athletes and six healthy male individuals with similar ages and normal rest electrocardiograms were studied. Maximal oxygen uptake (O(2)max) was measured by cardiopulmonary testing. The sinus cycle length (SCL), AV conduction intervals, sinus node recovery time (SNRT), Wenckebach cycle (WC) and anterograde effective refractory period (ERP) of the AV node were evaluated by invasive electrophysiologic studies at baseline, after intravenous atropine (0.04 mg/kg) and after addition of intravenous propranolol (0.2 mg/kg).
Athletes had a significantly higher O(2)max as compared with untrained individuals. The SCL was longer in athletes at baseline, after atropine and after the addition of propranolol for double-autonomic blockade. The mean maximal SNRT/SCL was longer in athletes after atropine and after propranolol. The WC and anterograde ERP of the AV node were longer in athletes at baseline, after atropine and after propranolol.
Under double-pharmacologic blockade, we demonstrated that sinus automaticity and AV node conduction changes of endurance athletes are related to intrinsic physiology and not to autonomic influences.
在本研究中，我们评估了耐力运动员和未经训练者在自主神经药理学阻断前后的窦房结和房室（AV）结电生理情况。
与未经训练者相比，耐力运动员窦性心动过缓和房室传导异常的患病率更高。我们实验室之前的数据表明，非自主神经因素可能是训练有素的运动员房室结不应期较长的原因。
对6名有氧训练的男性运动员和6名年龄相仿且静息心电图正常的健康男性个体进行了研究。通过心肺测试测量最大摄氧量（O₂max）。在基线、静脉注射阿托品（0.04 mg/kg）后以及加用静脉注射普萘洛尔（0.2 mg/kg）后，通过侵入性电生理研究评估窦房结周期长度（SCL）、房室传导间期、窦房结恢复时间（SNRT）、文氏周期（WC）和房室结前向有效不应期（ERP）。
与未经训练者相比，运动员的O₂max显著更高。在基线、阿托品注射后以及加用普萘洛尔进行双重自主神经阻断后，运动员的SCL更长。在阿托品注射后和普萘洛尔注射后，运动员的平均最大SNRT/SCL更长。在基线、阿托品注射后以及普萘洛尔注射后，运动员的房室结WC和前向ERP更长。
在双重药理学阻断下，我们证明耐力运动员的窦房结自律性和房室结传导变化与内在生理因素有关，而非自主神经影响。
