Sudden Death: Arrhythmias and Sport

We know very little about the risk of sudden death associated with exercise in young competitors, so the benefits versus the hazards of sports activity pose a clinical dilemma. However, we know from a study in the Veneto region of Italy that adolescents and young adults involved in competitive sport had a two and a half times higher risk of sudden death. The young competitors who died suddenly were affected by silent cardiovascular diseases, predominantly cardiomyopathies. Sport did not directly cause the deaths, but rather it triggered cardiac arrest in athletes with underlying diseases predisposing them to life-threatening ventricular arrhythmias.

Italy has a mandatory eligibility test involving nearly six million young people every year and the test leans heavily on the use of 12-lead ECG. In one 17-year study by the Centre for Sports Medicine of Padua involving nearly 34,000 athletes under 35 years old, over 1,000 were disqualified from competing on health grounds, 621 (1.8%) because the tests revealed relevant cardiovascular abnormalities.

In the US young athletes had physical examinations and personal and family history investigations, but 12-lead ECG was done only at the doctor’s discretion. The American Heart Association previously assumed that ECG would not be cost-effective for screening. The results of Italy’s 25-year experience of systematic pre-participation evaluation show that the Italian screening method is more sensitive than the limited US protocol. ECG is abnormal in up to 95% of patients with hypertropic cardiomyopathy (HCM), which is the leading cause of sudden death in an athlete. Comparisons between findings in Italy where ECG is used and research in the US showed a similar prevalence of HCM in non-sport sudden cardiac death, but a significant difference – 2% versus 24% – in sports-related cardiovascular events. This suggests we have selectively reduced sports-related sudden death from HCM because the Italian system, using ECG, identifies vulnerable young people.

ECG abnormalities have also been documented in the majority of athletes who died from other arrhythmogenic heart muscle diseases. A number of conditions now being picked up by ECG had only recently been discovered, so diagnosis was increasing. Researchers would shortly be examining the impact on mortality of the increased detection of potentially lethal problems.

From all the evidence that we have from 25 years experience in Italy, we can state unequivocally that screening is warranted. It is ethically and clinically justifiable to make every effort to recognise in good time the diseases that put these athletes at risk, and to reduce fatalities.

A 2005 European Society of Cardiology consensus document recommends that every young athlete involved in organised sport has a rigorous physical examination, a detailed investigation of their personal and family medical history and, most importantly, a 12-lead ECG. The consensus panel recommends that screening should start around the age of 12 years old to 14 years old and be repeated at least every two years. It should be performed by a physician with specific training who could reliably identify clinical symptoms and signs associated with cardiovascular diseases responsible for exercise-related sudden death. Those who tested positive according to set criteria should be referred for more extensive tests, and if that confirmed suspicions, barred from competition and training.

Screening of large athletic populations will have significant socio-economic impact and its implementation across Europe will depend on the different socio-economic and cultural backgrounds as well as on the specific medical systems in place in different countries. However, experience in Italy indicates that the proposed screening design is made feasible because of the limited cost of 12-lead ECG in a mass screening setting.