Dr. Med., Professor E.A. Gavrilova¹
Dr. Hab., Professor O.A. Churganov¹
PhD M.D. Belodedova²
PhD Y.V. Yakovlev^{3, 4}
PhD M.A. Rogozhnikov^{4, 5
1}North-Western State Medical University named after I.I. Mechnikov, Ministry of Health of Russia, St. Petersburg
²Herzen Russian State Pedagogical University, St. Petersburg
³S.M. Budyonny Military Academy of Telecommunications, St. Petersburg
⁴Saint Petersburg Academy of the Investigative Committee of the Russian Federation, Saint Petersburg
⁵Russian Customs Academy, St. Petersburg

Corresponding author: gavrilovaea@mail.ru

Abstract

Objective of the study was to analyze the global situation with sudden cardiac deaths in sports.

Methods and structure of the study. We analyzed on a systemic basis study reports on the subject by the relevant keywords including sports, sudden cardiac death, athletes etc. in Elibrary.ru and Pubmed databases.

Results and discussion. Prospective studies have found that in Italy, US and France the sudden cardiac deaths in sports are 2.5, 3.65 and 4.5 times higher than in the unsporting populations, respectively. As reported by Bohm P. et al., the sudden cardiac death risk exposure for men is 20 times higher than for women. The British Sports Sudden Cardiac Death Register reports 357 sudden cardiac death cases in the national sports, with the victims aged 29±11 years (27 years on average) and 92% male.

Studies have proven that the male sex hormones provoke cardiac hypertrophy with QT interval growth, potential electrical instability of the myocardium and ventricular arrhythmias. K.G. Harmon reported the research data on the sudden cardiac death incidence growth in sports with the sporting and competitive records. Researchers tend to believe that sudden cardiac death may be due to multifactor health conditions, disorders and cardiovascular diseases, plus some hereditary issues including structural genetic heart diseases and cardiac arrhythmias.

The sudden cardiac death exposure is reported most high for male athletes, particularly for the black football and basketball players, and for the endurance-intensive sports in general. Every third sudden cardiac death case in sports for the last few years was reported for athletes with structurally normal hearts, with the actual causes need to be analyzed on a sound research basis; although at this juncture some researchers tend to blame heart overstrains in excessive trainings as the main cause of autopsy-negative deaths.

Keywords: sports, sudden cardiac death, athletes.

Background. Sudden cardiac death cases that account for more than 90% of sports-related deaths are of special concern for the sports communities today. The sudden cardiac death studies are highly relevant today due to the sudden cardiac death growth statistics and alarming sudden cardiac death structure on the whole.

Objective of the study was to analyze the global situation with sudden cardiac deaths in sports.

Methods and structure of the study. We analyzed on a systemic basis study reports on the subject by the relevant keywords including sports, sudden cardiac death, athletes etc. in Elibrary.ru and Pubmed databases.

Results and discussion. The sudden cardiac death incidence is presently reported at 1 case per 3000 athletes per year, i.e. close to the lightning strike risk [10] and classified by age, race, gender, sport, sports records, skill levels and some other factors. Many analysts report and analyze only sudden cardiac death cases in competitions or professional sports communities net of the mass sports, with some researchers excluding cases of successful resuscitation from the sudden cardiac death statistics.

Thus K.G. Harmon [7] analyzed 13 sports-related sudden cardiac death study reports on the 9-40 year-olds’ deaths, with the sudden cardiac death incidence reported at 1 case per 917,000 to 1 case per 3000 athletes per year. The most sophisticated and inclusive studies report the sudden cardiac death incidence rate at 1:40,000 to 1:80,000. The author found the sudden cardiac death incidence in sports being probably much higher than commonly believed, and called for more effective sudden cardiac death -prevention programs.

Prospective studies have found that in Italy, US and France the sudden cardiac deaths in sports are 2.5, 3.65 and 4.5 times higher than in the unsporting populations, respectively. The US statistics report the physical stress related sudden cardiac death incidence in the young group being only twice as little than the mortality in road traffic accidents, twice as high as suicides, and 8 times higher than the drug overdose mortality [10]. This means that the sudden cardiac death should be ranked currently among the most challenging social problems.

The US statistics singles out the sporting groups highly exposed to the sudden cardiac death risks including male athletes (1 case per 37,790 athletes per year) versus 1:121,593 for female athletes; black athletes (1:21,491 versus 1:68,354 for white athletes); plus basketball and football players (1:8,978 and 1:23,689, respectively) [10]. As reported by Bohm P. et al., the sudden cardiac death risk exposure for men is 20 times higher than for women [2]

The British Sudden Cardiac Death Register reports 357 sudden cardiac death cases in the national sports, with the dead aged 29±11 years (27 years on average) and 92% male. The high sudden cardiac death incidence for male athletes is explained by the higher sympathetic tone and higher levels of catecholamines that are known to cause malignant arrhythmias. Studies have proven that the male sex hormones provoke cardiac hypertrophy with the QT interval growth, potential electrical instability of the myocardium and ventricular arrhythmias.

Mechanisms behind the high sudden cardiac death incidence for basketball players are still unclear. Although Marfan syndrome and associated aortic dissections in the sudden cardiac death totals are higher for male basketball players, they account for only a small share of the sudden cardiac death causes in this group. It should be noted in this context that basketball players are almost 15 times more exposed to cardiomyopathies related death risks. The Italian, Spanish, French and German sports health statistics rank football, track and field sports, cycling and swimming among the highest-sudden-cardiac-death-risk sports [2].

As reported G. Finocchiaro et al. [4], 245 out of 357 (69%) sudden cardiac death cases in the British sports involve the following actively training and competing athletic groups: football and track and field sports: 25% each; cycling and gymnastics: 8% each: swimming and weightlifting: 6% each: rugby: 5%; tennis and golf: 2% each; and boxing: 1%.

K.G. Harmon reported new research data on the sudden cardiac death risk growth in sports with the sporting and competitive records; whilst German analysts reported 142 out of 144 (99%) sudden cardiac death cases in amateur athletes [2]. Researchers tend to believe that sudden cardiac death may be due to multifactor health conditions and disorders and cardiovascular diseases, plus some hereditary issues including structural genetic heart diseases and cardiac arrhythmias [5, 10] that can be diagnosed both in structurally normal and structurally compromised hearts.

It is sensational that the modern Europe and some other nations report the autopsies of athletes diagnosing unexplained sudden cardiac death cases [1, 10] often referred to as the sudden arrhythmic death syndrome. The unexplained sudden cardiac death (autopsy-negative deaths as they are traditionally called in Russia) cases show no visible diseases, health issues or pathological changes and thus are often reported as acute cardiovascular system failures normally associated with life-threatening arrhythmias or cardiac arrests.

The British Sports Sudden Cardiac Death Register [4], qualifies 149 out of 357 sudden cardiac death cases (42%) with autopsy-negative death (sudden arrhythmic death syndrome) as the most common; followed by idiopathic left ventricular hypertrophy and/ or myocardial fibrosis – that account for 59 deaths (16%); then goes arrhythmogenic right ventricular cardiomyopathy: 48 deaths (13%); hypertrophic cardiomyopathy: 23 cases (6%); and dilated cardiomyopathy (2%). Coronary artery pathology is reported in 7% of the cases, with the anomalies diagnosed in most of the cases.

As reported G. Finocchiaro et al. [4], 288 out of 357 sudden cardiac death cases (81%) had no prior symptoms. Of 69 (29%) symptoms-reporting athletes, 27 (8%) reported palpitations (including five having histories of paroxysmal atrial fibrillation), 20 (6%) complained chest pains; 18 (5%) fainting; 4 (1%) was tested with falls in the physical stress tolerance; and 28 (8%) reported sudden cardiac death cases among their close relatives under 50 years of age [4].

Until recently, hypertrophic cardiomyopathy was long considered the leading cause for sudden cardiac death in sports, although the recent studies found that it may not be so. Thus K. Harmon [6] revised the well-known 1866 autopsy reports of athletes in the United States [9] to find 36% of the sudden cardiac death cases caused by hypertrophic cardiomyopathy; plus most of the autopsy reports were left beyond the statistics due to no structural abnormalities detected in the hearts. She argued that these deaths need to be covered by the statistics and qualified with the autopsy-negative cases to actually account for 34% of the cardiovascular-disease-related deaths to make it the key cause of the sudden cardiac death cases in the world-largest sudden cardiac death register. This figure agrees with a report by the US National College of Athletic Associations (NCAA) [3] which estimates the autopsy-negative cardiac death cases at 31% of the sudden cardiac death total. Note that proven hypertrophic cardiomyopathy and possible hypertrophic cardiomyopathy were diagnosed only in 3% and 11% of the total sudden cardiac death cases, respectively.

E. Marijon et al. [8] reported the sudden cardiac death statistics for athletes and physically active 35-minus year-olds in France, with the autopsy-negative deaths accounting for 36% and hypertrophic cardiomyopathy for only 10% of the total sudden cardiac death cases. G. Finocchiaro et al. [4] found the highest sudden cardiac death incidence rate (56% of the total) for the youngest (18-minus years old) athletes.

Regretfully, Russian sports-related sudden cardiac death statistics are non-reported and, hence, no incidence/ cause studies are available.

Conclusion. On the whole, the sudden cardiac death exposure is reported most high for male athletes, particularly for the black football and basketball players, and for the endurance-intensive sports in general. Every third sudden cardiac death case in sports for the last few years was reported for athletes with structurally normal hearts, with the actual reasons need to be analyzed on a sound research basis.

References

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