Lowering risks of sudden cardiac death in athletes

Sudden cardiac death (SCD) - an unexpected death from a loss of heart function - is a fatality that affects approximately one in 50,000 to one in 80,000 individuals in the athletic population worldwide.

“The prevalence of SCD is greater amongst athletes because certain underlying cardiovascular conditions are triggered during intense physical exercises,” said Dr Leslie Tay, a cardiologist at Mount Elizabeth Hospital in Singapore.

One reason that explains why some athletes drop dead is lack of awareness. Athletes tend to dismiss common warning signs of underlying heart conditions that may cause SCD, such as dizziness, palpitations or shortness of breath, because they are used to overexerting themselves.

“Not everyone is fortunate to have a warning sign,” explained Dr Tay. “For some athletes, the first presentation of any underlying heart condition is a cardiac arrest, a chaotic and dangerous heart rhythm which ultimately leads to SCD.”

However, he added that SCD is often preventable if a number of cardiovascular problems are diagnosed early.

Causes of SCD among athletes

There are more than 20 possible cardiovascular conditions that can be linked to SCD among athletes of various ages.

For patients above 35 years old, most of these cases are attributed to an acquired cardiovascular condition, such as coronary artery disease, according to Dr Tay.

“This is because conditions like coronary artery diseases take decades to develop, so they are more dangerous as you grow older,” he explained.

By contrast, for younger athletes, SCD usually stems from an inherited cardiac abnormality, which affects either the structure of the heart or its electrical system.

One example is hypertrophic cardiomyopathy (HCM), where there is an abnormal enlargement of the heart muscles, which obstructs blood flow. This condition is one of the most common congenital heart defects and is considered to be responsible for about 40 percent of SCD among young athletes.

Other genetic cardiovascular disorders that may contribute to SCD include Brugada syndrome and long QT syndrome.

Early diagnosis and treatment

Doing a simple evaluation is essential to single out athletes who are at risk of SCD.

“The goal is to identify cardiovascular conditions that are likely to trigger a cardiac arrest in people under strenuous exercise,” he emphasised.

In order to do so, Dr Tay recommends athletes or individuals who do an intense exercise programme to undergo a pre-participation evaluation (PPE) beforehand.

“A simple PPE can screen participants for potential acquired or inherited heart conditions to minimise the risks of SCD,” he added.

Typically, a PPE is done by examining the participant’s heart through several diagnostic tests.

One common test used to detect the heart’s structural defects, such as HCM, is an echocardiogram or heart ultrasound, while an electrocardiogram (ECG) is typically used to measure the heart’s electrical efficiency to spot conditions such as Brugada syndrome or long QT syndrome.

PPE also involves a standard treadmill test to screen for artery blockages by putting the patient’s heart under supervised stress through exercise.

“Based on the results of a PPE, treatments to control the progression of certain cardiovascular diseases can be implemented early, thereby preventing SCD,” explained Dr Tay.

Most of the treatments involve various types of medications or lifestyle changes, but some patients who are at high risk of SCD may need more invasive measures.

For example, patients who have suspicious symptoms of a sudden cardiac arrest or have survived one may need to implant a cardiac defibrillator, also known as implantable cardioverter defibrillator (ICD), to prevent future episodes.

This small device is implanted under the skin with wires attached to the heart chambers, which is used to monitor and treat the heart’s rhythm automatically. The device sends electrical shockwaves when a dangerous heart rhythm is detected to restore the heart to a normal rhythm and resuscitate the patient.

“However, for some untreatable heart conditions, patients may be entirely prohibited from continuing any form of strenuous physical activities or competitive sports,” added Dr Tay.

Such conditions may include Long QT syndrome, where simple triggers like strenuous exercise may cause an irregular heartbeat that leads to SCD.

Dr Leslie Tay is an interventional cardiologist practising at Mount Elizabeth Hospital in Singapore. He specialises in treating patients with complex  coronary artery disease and has special interests in sports cardiology and sports medicine. He is a certified clinical exercise specialist accredited by the American College of Sports Medicine since 2009. He is a strong advocate of preventive cardiology.

Mount Elizabeth Hospital
3 Mount Elizabeth, Singapore 228510
Tel: (+65) 6735 5000
www.mountelizabeth.com.sg

Orchard Heart Specialist Clinic
3 Mount Elizabeth #06-06
Mount Elizabeth Medical Centre
Singapore 228510