ABC | Volume 112, Nº3, March 2019

Updated The Brazilian Society of Cardiology and Brazilian Society of Exercise and Sports Medicine Updated Guidelines for Sports and Exercise Cardiology - 2019 Arq Bras Cardiol. 2019; 112(3):326-368 Table 2 – Electrocardiogram: changes due to exercise vs. changes suggestive of heart disease Physiological ECG findings in athletes Abnormal ECG findings in athletes Sinus Bradycardia (HR > 30bpm) T-wave inversion > 1 mm in 2 or more leads (except DIII, aVR and V1) Sinus arrhythmia ST-segment depression> 0.5 mm in 2 or more leads Ectopic atrial rhythm Pathological Q waves > 3 mm or > 40 ms in 2 or more leads (except DIII and aVR) Junctional escape rhythm Complete left bundle branch block 1 st degree BAV (PR interval > 200 ms) Nonspecific conduction delay with QRS > 140 ms 2 nd degree AVB Mobitz I (Wenckebach) Deviation of the electrical axis from – 30° to 90° Incomplete right bundle branch block Left atrial overload Isolated QRS voltage criterion for LVH Right ventricular hypertrophy pattern with RV1 + SV5 > 10.5 mm and axis deviation > 120° Ventricular pre-excitation Early repolarization QT interval > 470 ms in men and > 480 ms in women ST-segment elevation accompanied by T-wave inversion in leads V1 to V4 in Black athletes QT interval < 320 ms Brugada pattern Sinus bradycardia < 30 bpm or sinus pauses > 3 s Atrial tachyarrhythmia Ventricular extrasystoles with 2 or more 10-second ECG episodes Paired ventricular extrasystoles and NSVT AVB: atrioventricular block; BPM: beats per minute; ECG: electrocardiogram; HR: heart rate; LVH: left ventricular hypertrophy; NSVT: nonsustained ventricular tachycardia. Table 3 – Different types of electrocardiographic abnormalities in relation to age found in an unselected European population of 32,652 subjects who underwent sports pre-participation screening < 20 years (n = 2.430) % 20-29 years (n = 2.430) % > 30 years (n = 2.430) % Incomplete RBBB, increased PR interval, early repolarization pattern 73.1 37.9 30.1 Inverted T-waves 9.5 38.6 37.9 R/S wave voltage increase 3.1 4.6 7.2 RBBB 10.9 12.1 10.9 LAHB, LBBB 2.1 5.7 13.3 Pre-excitation pattern 1.3 1.1 0.6 LAHB: left anterior hemiblock; RBBD: right bundle branch block; LBBB: left bundle branch block. Adapted from Pelliccia et al. 73 repolarization (50% to 80%). Such findings are usually due to physiological adaptations related to athlete’s heart syndrome. 33 Athletes may also present voltage criteria for LVH, which reflects remodeling of this cavity, although without pathological Q-waves, electrical axis deviation, atrial overload or repolarization changes. 31,32 These physiological changes in ECG should be clearly separated from patterns suggestive of heart disease, which can be recognized by repolarization changes, pathological Q waves, marked intraventricular conduction defects, pre-excitation, short or long QT intervals, and Brugada syndrome. These findings are rare (less than 5%) but may express some cardiomyopathy or channelopathy that could predispose the athlete to SD. 33 Another important point concerns atrial dilation (resulting from regular training) to meet increased cardiac demand during exercise, although this is not fully understood. Nevertheless, despite this dilation, atrial function seems to be preserved in athletes, but not in patients with structural heart disease. 34 Other less common findings that can be identified in athletes are sinus pauses < 3 s (mainly during sleep) and second-degree bicuspid aortic valve (BAV) type I (Wenckebach). Such findings generally disappear during effort and with the administration of substances. Changes that can be considered cardiac adaptations to physical exertion should not cause alarm, and participation in competitive sports should not be prohibited without further evaluation. On the other hand, findings suggestive of heart disease, even if asymptomatic, should be investigated, especially in the absence of a positive 333