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 and biochemical differences between men and women, including smaller stature, lower body mass, smaller LV diameter, less testosterone and a different physical work capacity. 259 In hemodynamic terms, higher resting HR have been observed, although maximum levels during exercise are reached in a manner similar to men. Systolic BP and systolic volume increase less on effort, and maximal O 2 consumption (VO 2 max) is lower. Nevertheless, female cardiac output is 5% to 10% higher than that of males at any level of submaximal oxygen consumption. 260 In absolute values, female work capacity is lower, but when assessed at the same intensity percentage, the cardiovascular performance of men and women are similar. Since physical training can result in a series of cardiovascular system modifications and adaptations, knowing how to differentiate physiological responses due to regular exercise from pathological ones can be a challenge when performing detailed clinical evaluations of athletes. 7.2. Complementary Exams 7.2.1. Twelve-Lead Electrocardiogram 7.2.1.1. Electrocardiogram: Physiological Changes vs. Changes Suggestive of Heart Disease Both physiological and pathological adaptations may differ between female and male athletes in ECG. However, data on specific ECG differences between genders are limited. Using the criteria of Pelliccia et al. (2000), 261 women had a higher prevalence of normal ECG than men (78% vs. 55%) in a cohort of European Olympic athletes. On the other hand, according to the latest Seattle criteria, 262 no significant differences were observed between genders (96% of males and 97% of females had normal ECG). This contrast could be justified by the fact that the Seattle Criteria are much more rigorous, which increases specificity without sensitivity loss. Female athletes appear to have a lower prevalence of physiological changes in ECG, especially regarding isolated increases in QRS complex amplitude (in about 10% of women), incomplete RBBB and early repolarization (four times less than men). 263,264 However, female athletes had a higher frequency of QT interval increase, as well as inverted T-wave in the V1-V2 leads (1% vs. 0.2% in male athletes), 265 such findings are considered non-pathological adaptations. Inverted T-waves in the inferior and/or lateral walls are more prevalent in male athletes, being more commonly associated with underlying structural heart disease. 266 On the other hand, anterior precordial T wave inversion is more common in women and, when limited to V1-V3 leads, does not appear to be related to structural heart disease. 267,268 However, ventricular repolarization changes in lateral leads are less common and should always serve as a warning for a possible pathology. 269 One important point to consider is that the international guidelines for interpreting ECG in athletes do not differ according to gender, but are unanimous in stipulating a higher QTc interval cut-off point for women than men, since women, regardless of cardiac remodeling, have longer QTc intervals than men (≥ 480 ms vs. ≥ 470 ms, respectively). 101,270 7.3. Echocardiogram The echocardiogram is one tool available for PPS and determining sports eligibility. In a study of 600 female athletes who participated in different sports, it was found that the LV cavity is rarely greater than 54 mm (a threshold value for normality in women) and never above 66 mm. The thickness of the LV wall rarely measures over 11 mm, reaching a maximum of 13 mm, usually in blacks. 225,271 Finocchiaro et al. 264 confirmed these findings: none of the women in their sample had an LV wall thickness > 12 mm, and only 7% had a LV end-diastolic diameter > 54 mm. In fact, these results are clinically relevant, since a LV cavity < 54 mm can distinguish, for example, an “athlete’s heart” from HCM with excellent sensitivity and specificity. 272 It has long been known that one adaptation to regular physical training is increased LV mass, observed mainly in endurance athletes. However, when LV wall thickness is accompanied by a reduction in cavity size, a pathological process such as HCM should be suspected. LV wall thickness > 12 mm in men or > 10 mm in women is considered abnormal in white athletes, and further investigation is necessary. 273 In black athletes, an LV wall thickness of 11 mm can be observed, which can reach up to 12 or even 13 mm in exceptional situations. 271 Since none of the athletes Finocchiaro et al.’s sample had a LV wall ≥ 13 mm, it would be reasonable to infer that an LV wall thickness of 13 mm probably represents the upper physiological limit of LV hypertrophy in black and asymptomatic athletes where there is no family history of HCM. Recent experiments have demonstrated that women with “athlete’s heart” have eccentric LV hypertrophy. Initially, there is an increase in the cavity which, although smaller (5%) than that of a man, is larger when indexed to body surface. LV wall thickness and LV mass do not increase proportionally, being smaller than those of male athletes (23% and 31%, respectively). It is suggested that a relative LV wall thickness > 0.48 is a marker of pathology. 269 D’Ascenzi et al. 274 investigated the morphology and function of the left and right atria in competitive volleyball athletes, observing a biatrial increase with normal filling pressures and low complacency. In women, these characteristics are typical of athlete’s heart and should be thus interpreted as a physiological adaptation to intense physical training. 7.4. Exercise Testing Prior to this decade, the exercise stress testing was considered less accurate when diagnosing CAD in women. However, more recent studies have vindicated its effectiveness, especially for variables besides ST-segment. Women are more likely to have baseline ST-segment and T-wave changes, as well as ST-segment depression, during exercise. This is believed to be a consequence of a “digoxin-like” estrogen effect, since the changes seem 354