Risk of Sports-Related Sudden Cardiac Death in Women
abstract
This abstract is available on the publisher's site.
Access this abstract nowSudden cardiac death (SCD) is a tragic incident accountable for up to 50% of deaths from cardiovascular disease. Sports-related SCD (SrSCD) is a phenomenon which has previously been associated with both competitive and recreational sport activities. SrSCD has been found to occur 5-33-fold less frequently in women than in men, and the sex difference persists despite a rapid increase in female participation in sports. Establishing the reasons behind this difference could pinpoint targets for improved prevention of SrSCD. Therefore, this review summarizes existing knowledge on epidemiology, characteristics, and causes of SrSCD in females, and elaborates on proposed mechanisms behind the sex differences. Although literature concerning the aetiology of SrSCD in females is limited, proposed mechanisms include sex-specific variations in hormones, blood pressure, autonomic tone, and the presentation of acute coronary syndromes. Consequently, these biological differences impact the degree of cardiac hypertrophy, dilation, right ventricular remodelling, myocardial fibrosis, and coronary atherosclerosis, and thereby the occurrence of ventricular arrhythmias in male and female athletes associated with short- and long-term exercise. Finally, cardiac examinations such as electrocardiograms and echocardiography are useful tools allowing easy differentiation between physiological and pathological cardiac adaptations following exercise in women. However, as a significant proportion of SrSCD causes in women are non-structural or unexplained after autopsy, channelopathies may play an important role, encouraging attention to prodromal symptoms and family history. These findings will aid in the identification of females at high risk of SrSCD and development of targeted prevention for female sport participants.
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Risk of sports-related sudden cardiac death in women
Eur Heart J 2021 Dec 11;[EPub Ahead of Print], D Rajan, R Garcia, J Svane, J Tfelt-HansenFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
This review article offers a comprehensive overview of the incidence, characteristics, and clinical correlates of sport-related sudden cardiac death (SrSCD) in women vs men. The huge difference in incidence between sexes is the most prominent and consistent information, with male: female ratio in SrSCDs ranging from 7:1 to 32:1. To quote, for example, data from France, the incidence is 0.59–2.17 per million female sports participant-years vs. 11.24–33.84 per million male sports participant-years.1 Similarly, in the US, the SrSCD incidence in females is 0.66 per million female athlete-years vs 5.01 in males per million male athlete-years.2
One may argue that the lower incidence of SrSCD in females is simply consequence of their lower participation in sport activities. However, this hypothesis is easily denied from the actual number of women engaged in sport at all levels: ie, women represented 45% the athlete’s population participating at the recent Olympic Games, and even higher proportion of women are regularly involved in leisure-time athletic activities.
Type of sport (ie, participation in endurance disciplines) and higher intensity of exercise programs have also been postulated as determinants of SrSCD, but this theory clashes with the evidence of the contemporary large participation and high level of achievement of women in the most demanding endurance disciplines, such as marathon running, road cycling, triathlon, or cross-country skiing, where adverse events are reported virtually only in male competitors.
Incidence of SrSCD is largely dependent from the size of population engaged in a certain discipline, with the most popular sports naturally presenting a higher absolute SrSCD rate; in the US, basketball is more commonly associated with SrSCD, whereas in Europe soccer (in males) and then jogging/running, cycling, and swimming are more commonly associated with SrSCD in both sexes.
These data simply confirm that sport is not, per se, the cause of SrSCD, but only the trigger of the event in presence of an underlying, cardiac disease. Accordingly, the previous literature has extensively reported the most common pathologic conditions associated with sudden death, such as cardiomyopathies, (eg, hypertrophic or arrhythmogenic cardiomyopathy), coronary artery disease or channelopathies (eg, long QT syndrome, early repolarization, catecholaminergic ventricular tachycardia).
Well, even in the presence of a known pathologic substrate, women seem to have less proclivity than men for developing ominous ventricular arrhythmias. For instance, in patients with HCM, exercise-induced ventricular arrhythmias are reported more commonly in men than in women. Similarly, more men experience malignant arrhythmias in dilated cardiomyopathy and arrhythmogenic cardiomyopathy.3
The different hormonal environment may explain part of these differences; when an arrhythmogenic substrate is present, elevated testosterone levels, as well as lower oestradiol levels, are associated with higher risk of malignant ventricular arrhythmias.
Indeed, proportion of HCM in the French registry accounted for only 14% of female SrSCDs vs 51% of male SrSCDs.1 Overall, in the same registry 42% of SrSCDs in women were nonstructural, vs 4% in men, suggesting that the largest proportion of SrSCD in women have a normal cardiac pathologic examen.
The role of doping agents and drugs of common use (antidepressant, stimulants) remains to be fully elucidated. Anabolic androgenic steroids are associated with cardiac hypertrophy, arrhythmias, and SCD. Multiple studies showed that women were less likely than men to use anabolic steroids placing them at lower risk.4 Finally, social or behavioral differences between the genders, eg, a proclivity for men to use performance-enhancing drugs or overexert, could also contribute to the dissimilarity in SrSCD incidence.
Take-home message: The review article confirms the huge difference of Sr SCD among sexes and delineates the potential mechanisms protecting women’s hearts. The available information is still incomplete and further studies are needed to uncover the mechanisms by how SrSCD can be prevented.
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