Jan - Feb 2006, Livewell Magazine
When the heart stops suddenly
Why do young people fall prey to sudden cardiac arrest?
They are young. They are rather fit. They exercise regularly. They all die abruptly, leaving behind their loved ones flabbergasted and in shock. Their relatives and friends often say they lead a rather healthy lifestyle and looked perfectly healthy and never complained of any heart or chest pain. They have one thing in common. Their lives were claimed by sudden cardia arrest (SCD).
According to Dr Michael Lim, Consultant Cardiologist & Physician, Singapore Heart, Stroke and Cancer: "SCD is an unexpected death from a cardiac cause, heralded by abrupt loss of consciousness within a short time period, generally less than 1 hour from the onset of symptoms. Pre-existing heart disease may or may not have been known to be present, but the time and mode of death are unexpected."
SCD is different from heart attack. "SCD is usually caused by electrical instability of the heart that results in a potentially fatal outcome. The electrical instability causing SCD is most commonly caused by coronary heart disease (CHD)," says Dr Lim.
Dr Lim, who is also the President of the Asia Pacific Society of Cardiology explains: "SCD Prodromal symptoms are often non-specific, and those taken to indicate angina (chest pain), tachyarrhythmia (palpitation or thumping of the heart), or congestive heart failure symptoms (shortness of breath) should only be seen as suggestive of the diagnosis,"
Most of the episodes of SCD occur out of hospital, and only a few of these patients survive. Many of the SCD victims are asymptomatic before the event and may not even have identifiable risk factors. Most SCD patients do not have any warning symptoms. Sudden cardiac death is often the first manifestation of CHD.
According to Dr Tan Jit Seng, the medical officer in Tengah Air Base who was credited with the successful resuscitation of a serviceman recently, undetected heart disease or some congenital abnormalities in the heart can cause SCD. During intense physical or athletic activity, the rush of adrenaline often acts as a trigger for sudden cardiac death, when these conditions are present. However in most cases, you do not need to be exercising strenuously in order to be at risk of SCD, and a seemingly healthy person can be at risk when he is at rest. "SCD deaths are also not unheard of here, there are 87 such cases a year in Singapore among men of ages 18 to 45," says Dr Tan.
Dr Low Lip Ping, chairman of the Singapore Heart Foundation points out that ventricular fibrillation (VF) is far more dangerous than SCD. VF can be described as millions of short circuits occurring in the heart, causing the heart pump to fail and stop delivery of blood oxygen and nutrients to vital organs, especially the brain. Death can occur within minutes.
SCD can be prevented if high risk patients are identified and referred to a cardiologist. The cardiologist may decide to implant an electrical medical device called an implantable cardioverter defibrillators (ICD) - a matchbox size machine implanted on your chest well that deliver electric shock automatically to the heart. "This device has shown to be effective in preventing sudden cardiac death in 99% of cases," says Dr Lim
According to Dr Lim, the majority of individuals who suffer SCD have coronary heart disease. He adds that the epidermiology of sudden cardiac death parallels that of coronary heart disease to a large extent. The risk factors for sudden cardiac death are similar to coronary artery diseases, which include hypertension, elevated cholesterol levels, diabetes, strong family history, obesity, old age, leading a sedentary lifestyle and smoking.
Screening for CHD risk factors, such as high blood pressure and high cholesterol and effective control of these factors aids in reducing the risk of SCD. In those with known CHD, various types of tests can be conducted to identify those at higher risk of heart attack and SCD.
The best approach to manage these events, according to Dr Lim, is to initiate cardiopulmonary resuscitation within the first 4 minutes of the cardiac arrest and to deliver advanced cardiac life support, including defibrillation, within the first 8 minutes. Ventricular fibrillation is the type of arrhythmia most responsive to defibrillation (shocking the heart with electricity from specialised machine). However, it rapidly deteriorate and defibrillation becomes ineffective. The success rate of resuscitation is reduced by 8% to 10% after each minute of arrest.
In any case, time if of essence in a resuscitation of SCD. It should be initiated at once, as any delay beyond this period may result in permanent brain as well as cardiac damage. The chances of effective resuscitation also rapidly decrease teh longer the delay before it is initiated, vice-versa.
Remember these healthy heart principles
3 Highs (high in fibre, freshness, plant-based protein). 5 Lows (low in fat, cholesterol, salt, sugar and alcohol). Being 70% full is just right! Have small frequent meals instead of 3 big meals. Say no to cigarettes. Manage stress. Walk 3 km per day for at least 5 times a week. |
