Sudden death syndrome screening
Sudden death in sport (SD) is defined as natural death that occurs within one hour of onset of symptoms in a fit individual participating in, usually, an elite level sport. Sudden cardiac death contributes to 93% of all sudden deaths in sport. This apparently occurs in a person without previously recognized predisposing cardiovascular conditions. In some instances, pre-existing symptoms may already have been present, but the time and mode of death are unexpected. This excludes cerebrovascular, respiratory, and traumatic and drug related causes which are the origin of the other 7% of sudden deaths". A significant cause of death in contact sports is commotion cordis, which is referred to in one of my other articles. I strongly suggest you to visit sudden death syndrome screening to learn more about this.
The incidence of SD is estimated to be about one death in 1 in 200000 per year with an average of 300 deaths per year, but the incidence could be higher according to some European studies. An Italian study suggested an incidence of 1.6 - 2.3 per 100000 athletes per year (2.1 per 100000 per year due to cardiovascular causes) and 0.8. This clearly reflects an increased incidence in athletes.
- Most of the cases are asymptomatic
- In the rest, symptoms occurring prior to SD are
i. angina (chest pain)
ii. Dyspnoea (breathlessness)
iii. Palpitations (awareness of one's heart beating)
iv. Pre syncope or syncope (light headedness or fainting)
- Hypertrophic Cardiomyopathy (HCM)non obstructive, obstructive, ischemic, etc - Valvular disease: Aortic stenosis, Mitral Valve Prolapse
- Coronary artery disease
- Congenital anomalies of coronary arteries
- Idiopathic concentric left ventricular hypertrophy
- Aortic rupture
- Right ventricular dysplasia (ARVC)
- Myocarditis: viral, sarcoidosis, amyloidosis
- Arrhythmias and conduction defects Congenital heart disease: Marfan's, WPW syndrome
- Pulmonary embolisation
- QT interval increasing: cisapride, domperidone, chlorpromazine, haloperidol, pimozide, erythromycin and clarithomycin
- Epinephrine, ephedrine, cocaine, etc
- Performance enhancing: erythropoietin (hyperviscocity & thrombogenesis) anabolics
Commotio cords (CC)
Is sudden impact on the precordium, during a vulnerable period of the cardiac cycle cause ventricular fibrillation and sudden death without any visible injury to the sternum or ribs, e.g. contact sport? In 80% of cases of sudden cardiovascular death in athletes, the cause has been identified to be either hypertrophic cardiomyopathy or arrthymogenic right ventricular cardiomyopathy.
In general, in athletes > 35 years of age, atherosclerotic coronary arterial disease is the leading cause while in those < 35, it is often caused by HCM, a silent cardiac condition which gets unmasked during performance.
Geographical Considerations in Etiology
In the US, hypertrophic cardiomyopathy is the major cause of SD. In contrast, in Europe, cardiac arrhythmias and abnormal cardiac arterial anatomy is supposed to be the leading cause. An interesting statistic is that of all the sudden deaths in the US, 50% were found to be amongst athletes of Afro-American origin. In Asia, on the contrary, (the Philippines, Thailand, Japan), Brugada syndrome seems to be the most common cause of natural death in men younger than 50 years of age. This relates to cardiac arrest occurring during sleep or at rest and not during a sport performance. An importance observation is these cases had been the reports episodes of nightmares occurring prior to the event. This might suggest a role of the sympathetic nervous system.
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