Heart Disease Prevention - How To Prevent Sudden Cardiac Death?

It is not uncommon to hear about the sudden passing of people who are practically healthy. Among those victims, some were young athletes. How did all these happen? According to cardiologists, this is almost always due to sudden cardiac arrest (SCA), a condition in which the heart stops pumping effectively… More details can be found at: 

Heart Disease Prevention - How To Prevent Sudden Cardiac Death?

Is Comprehensive Screening Good Enough to Detect Sudden Cardiac Death?

Is comprehensive heart screening sufficient for young people who are engaging in aggressive exercises such as Marathon running, military training, etc? Should they also undergo additional testing with treadmill exercise and echocardiography (cardiac ultrasound)?

What is sudden cardiac death? As defined by American Heart Association, sudden cardiac death (SCD) or cardiac arrest is the sudden, abrupt loss of heart function in a person who may or may not have diagnosed heart disease. It just occurs immediately or shortly after the symptoms appear.

Every year, sudden cardiac death causes about 166,200 deaths among adults in the United States before reaching a hospital or emergency room.

For people below the age of 35, SCD has many causes. Not all of these causes are due to cardiac problems and only some of these can be detected by screening. Patients who die suddenly are commonly caused by cardiovascular disease, in particular, coronary heart disease (CAD), but it rarely happens to younger age group.

No doubt treadmill ECG stress testing can be used to detect CAD. Nevertheless, it does have its own limitations. For example, it has a false positive result of 10 to 20 percent. In other words, if CAD occurs in 1 per 1,000 people screened, out of 25,000 persons tested, 25 might have CAD. This means that 2,500 to 5,000 might have false positive stress results, and these people have to undergo further testing, such as nuclear imaging and coronary angiography, which may have other risks such as radiation exposure.

It is unjustified to place such a big percentage of people to these risks, as this would certainly outweigh the benefit of detecting a few with CAD. Obviously, stress testing should only be used for those at higher risk such as older men or those with significant risk factors for heart disease.

For youngsters, a more common cause of SCD is hypertrophic cardiomyopathy (HCM). It is an inherited condition with abnormal thickening of the heart muscle. People with HCM will show ECG abnormalities.

In fact, adding ECG to a history and physical examination in athletes, and referring only those with ECG abnormalities for more tests was proved to be an effective mean to minimize the risk of SCD due to HCM. Such approach has also been shown by studies in Italy and endorsed by the International Olympic Committee and European Society of Cardiology.

Meanwhile, prevention and control of risk factors like diabetes, high cholesterol, hypertension (high blood pressure), obesity, and smoking through healthy lifestyles should be encouraged to reduce SCD.

What Is The Chance of Surviving Sudden Cardiac Arrest Outside Hospital?

There is no doubt that time is very critical if a person is to survive sudden cardiac arrest (heart attack). According to the American Heart Association, the chance of survival from sudden cardiac arrest decreases by 7 to 10 percent with every passing minute.

The average survival rate in Singapore for people who suffer from heart attack outside hospital is rather poor: between 1.5 percent and 3 percent. This is because of the small number of people here who are trained in CPR (Cardiopulmonary Resuscitation) and the limited effectiveness of performing CPR.

CPR is a technique that involves mouth-to-mouth rescue breathing and chest compressions. It helps artificially circulate oxygen-rich blood for the victims, keeping their brain and vital organs alive. In most cases of sudden cardiac arrest, the heart can also have an irregular rhythm, which can be corrected using an automated external defibrillator (AED).

AED is a portable computerized machine delivers an electric shock to re-establish normal heartbeats. Being easy to use, AED can allow non-medically trained people help save lives. The people who use it just need to follow the step-by-step instructions from the machine via voice prompt. In Singapore, AEDs have been installed at sports centers, stadiums and swimming pools, as well as major public places such as hotels and shopping centers.

The American Journal of Sports Medicine revealed that around 1 to 5 sudden cardiac deaths occur each year for every 1 million athletes below the age of 35. People with the age below 35 years old having sudden cardiac arrest are usually the result of coronary artery disease. Sudden cardiac arrest victims who are below 35 years old are due to a genetic disorder known as hypertrophic cardiomyopathy (HCM), an abnormal thickening of the heart muscle.

People with this type of disorder are predisposed to abnormal heart rhythms, which can be triggered during vigorous exercise. Though most of the reports of athletes dying from sudden cardiac arrest were men, this does not rule out women.

In fact, HCM could happen equally in both sexes. One possible reason for more reported cases of cardiac arrest in men is that men are more likely to engage in vigorous and competitive sports. In comparison, women's level of participation in intensive sports is much lower than that of men. That is why women are less exposed to exercise-induced cardiac arrest.

Recognizing the warning signs of a possible heart condition is very important. Those who get palpitations, breathlessness or dizziness, and those who have a family history of heart problems should consult their doctor.

Unfortunately, identifying athletes who are vulnerable to the condition is not so easy. Some heart problems cannot be detected in tests, and screening for rare congenital conditions can be expensive, too.

Nevertheless, people who want to engage in vigorous physical activity, such as marathons or hiking expeditions, are still urged to go for a thorough screening.