A big challenge for GPs is to identify those who may be at risk of sudden death while exercising, writes Dr Fionnuala Quigley.
General practitioners are often the first person to be called when a young person dies suddenly while exercising. The vast majority of these are considered sudden cardiac deaths. GPs have a key role in dealing with the family when this tragedy occurs. In addition, they have a responsibility in ensuring that family members are carefully screened so that further tragedy may be averted.
Unfortunately, the vast majority of athletes who die suddenly do not have any symptoms. However, young people can rarely present to their family doctor with symptoms related to underlying cardiovascular abnormality. This small group may be at risk of sudden cardiac death if these symptoms are not recognised and appropriately investigated. Identification and treatment of high-risk people may substantially reduce their likelihood of dying suddenly. Therefore, it is essential that GPs should have awareness and relevant knowledge in this area. The following points highlight some important issues.
Incidence of sudden cardiac death in sport
There is a shortage of robust data currently available. A survey of the causes of sudden death in sport in the Republic of Ireland (age range from 15 to 75 years and included all levels of sports activity) from January 1, 1996 to December 31, 1997 suggests that the incidence is low, one in 600,000 of the population (this was calculated on the basis that there were 51 cases over 10 years with a population of approximately three million).
This incidence level is significantly lower than that found in studies in the United States, where the incidence of sudden death in young competitive athletes is believed to be two per 100,100 per year. The incidence in Italian competitive athletes (age 14-35 years) appears to lie between that of the Irish and American studies, reported at 3.6/100,000. The difference in incidence levels between countries is difficult to explain, but may merely reflect the small number of studies to date.
Despite the variability in the reported incidence of sudden death in sport, it does seem that the risk is 2.5 times higher in athletes than in age matched non-athletes.
It has been suggested that the risk of sudden cardiac death increases with increasing intensity of exercise and increasing level of competition. The relative risk of death during sport participation appears to be greatest in the case of cardiomyopathies and congenital coronary artery anomalies. Possible causes of sudden cardiac death in sport.
Most studies agree on the association between sudden cardiac death in sport and the following abnormalities:
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The commonest cause in those over 35 years appears to be atherosclerotic coronary artery disease
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The commonest causes in those less than 35 years are:
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Hypertrophic cardiomyopathy is the most commonly reported cause (prevalence is one in 500 in the general population)
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Congenital coronary artery anomalies
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Arrythmogenic right ventricular cardiomyopathy
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Dilated cardiomyopathy
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Myocarditis
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Aortic dissection (usually in the context of Marfans syndrome);
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Electrical disorders: Channelopathies such as congenital long or short QT syndromes, Brugada syndrome, cathecholaminergic polymorphic ventricular tachycardia, Wolff Parkinson White syndrome;
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Commotio cordis, which can be caused by projectiles such as hockey pucks, or bodily contact such as karate blows;
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Ventricular fibrillation can be induced without structural injury to the ribs, sternum or heart
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Unknown. A normal heart at post mortem has been found in one to sevenper cent of cases. Channelopathies may well account for a number of these previously considered unexplained deaths as in these cases the heart would be morphologically normal
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Relevant symptoms
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Syncope or near syncope, particularly if exercise related
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Exertional chest pain
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Shortness of breath or fatigue out of proportion to the degree or physical activity;
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Palpitations or irregular heart beat
Family history
When presented with a young person with symptoms that could be attributable to a cardiac abnormality, it is critical to take a full and detailed family history.
The following questions should be included:
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Has anyone in your family under the age of 50 years: Died suddenly and unexpectedly?
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Been treated for recurrent fainting?
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Had unexplained seizure problems?
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Had an unexplained drowning while swimming?
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Had an unexplained car accident?
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Had heart transplantation?
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Had a pacemaker or defibrillator implanted?
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Been treated for irregular heartbeat Had heart surgery?
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Experienced sudden infant death (cot death)?
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Does anyone in the family have Marfans syndrome?
If the answer is yes to any of the above, an underlying cardiovascular condition needs to be considered
Clinical examination
A thorough clinical examination should be performed in all cases, paying particular attention to the following:
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Blood pressure
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Murmurs (in hypertrophic cardiomyopathy 20 per cent will have a systolic murmur which is exaggerated on performing the Valsalva manoeuvre or from changing from the supine to the standing position)
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Radial and femoral pulses
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Stigmata of Marfans syndrome
Referral to a specialist
The following should be considered for referral to a specialist (ideally a cardiologist with a particular interest in the area):
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Family members of a young individual who has died unexpectedly
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Those with suggestive symptoms, particularly exercise related syncope, near syncope, chest pain, palpitations, and shortness of breath or fatigue out of proportion to the degree of physical exertion
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Positive finding on examination
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Abnormal ECG
The role of GPs in pre-participation cardiovascular screening of young athletes
Ideally GPs should be involved, but such a role would potentially have major financial and manpower implications. The ‘Lausanne Recommendations’ (International Olympic Committee Medical Commission) have advised the following for all participants at the beginning of competitive activities until aged 35 years
Personal history
Family history
Physical examination
12’leadECG
The rationale for including an ECG is that it is abnormal in 95 per cent of cases of hypertrophic cardiomyopathy and in 80 per cent of individuals with arrhythmogenic right ventricular cardiomyopathy. The Italian Pre-Participation Screening Model, which includes an ECG, has shown 90 per cent reduction in mortality.
However, the current pre-participation cardiovascular screening of athletes in the United States does not include an ECG. The false positives associated with the ECG as well as the financial implications and logistics of ECG interpretation remain a concern in the US.
Cardiac arrest during sport
Although a relatively rare event, GPs, particularly those actively involved as team sport physicians, need to be aware that cardiac arrest can occur in young people while participating in sport.
The following points need to be considered:
Prompt recognition and diagnosis (brief seizure-like activity or involuntary myoclonic jerks have been reported in approximately 50 per cent of young athletes with sudden cardiac arrest);
Presence of a trained rescuer (that is, trained in basic life support)
Early defibrillation improves survival for young athletes with sudden cardiac arrest. The single greatest factor affecting survival from sudden cardiac arrest is the time interval from cardiac arrest to defibrillation.
Conclusion
One of the greatest challenges for GPs is to identify’ those who may be at risk of sudden death while exercising Careful history taking, clinical evaluation and appropriate referral for specialist opinion, may go some way towards averting these tragic deaths In the future it is anticipated that all young athletes in Ireland will require pre-participation evaluation and this will involve major commitment by general practitioners.
References available on request.
Dr Fionnuala Quigley is a GP in West Cork, a senior lecturer on the Masters Degree Programme in Medical Science, Sport and Exercise Medicine at University College Cork, and a trustee of the charity CRY (Cardiac Risk in the Young)