Sudden cardiac death (SCD) is the unexpected death due to cardiac causes occurring in a short period of time in a person with known or unknown cardiac disease. It is the catastrophic culmination of sudden loss of heart function such that blood flow to the rest of the body, including the vital organs. This sudden loss of heart function is known as sudden cardiac arrest (SCA) and, if left untreated, or if treatment is unsuccessful, leads to sudden cardiac death.

The immediate cause of SCA, and therefore SCD, is a severe disturbance of the electrical activity of the heart (an arrhythmia). Most people who experience SCA have underlying heart disease. The commonest type of heart disease which leads on to SCA is coronary artery disease, where the blood flow to the heart muscle is reduced because of blockages or narrowing of the blood vessels of the heart. This is the type of heart disease that leads on to heart attacks. SCA and heart attack are not the same thing. A heart attack can cause SCA but SCA can also occur without the person having suffered a heart attack.

There are other less common types of cardiac diseases which can lead on to SCA, including diseases of the heart muscle, heart valve disease (often as a result of rheumatic fever in childhood), congenital heart disease (abnormal heart structure that you are born with and a cause of SCA in children), and abnormalities of the electrical system of the heart.

The risk factors for SCA are essentially the risk factors for coronary artery disease which is by far the commonest cause of SCA. They include family history of heart attacks or blood vessel disease of the heart in your parents or brothers and sisters, high cholesterol, high blood pressure, diabetes, obesity, cigarette smoking, sedentary lifestyle. Other contributory factors are family or personal history of the other types of heart diseases which can lead to SCA, male gender, (as men are 2-3 times more likely to suffer SCA), excess alcohol intake, previous heart attack, age, use of illicit drugs such as cocaine and amphetamines, and some nutritional imbalances.

Most people who suffer an out-of-hospital SCA will die. Therefore prevention of SCD is more likely to be possible if we prevent SCA. Reducing the risk for coronary artery disease and for heart attacks will reduce the risk for SCA and death.

These risks are modifiable by changing lifestyle and treating underlying conditions like high blood pressure and diabetes. All persons should know their personal and family history of disease and should screen for risk factors by undergoing regular physical examinations including measurements of blood pressure, weight, waist circumference and cholesterol starting from age 20 and blood sugar from age 45. How often these should be repeated will depend on the results and the other risk factors which exist.

A healthy diet should be adhered to. This is one which is rich in root vegetables, fruit, peas and beans, whole grains and oily fish and restricted in red meat, added sugar, salt and saturated and trans fats. Regular physical activity should be engaged in unless there is some physical impediment to this.

Don’t smoke cigarettes and seek help to stop if you are currently smoking. Lose weight if you are overweight, reduce your intake of alcohol to no more than 2 drinks per day for a man and 1 drink per day for a woman.

Following these simple principles and maintaining them long term will ultimately improve your overall health, reduce your risk of heart disease and reduce your risk of sudden cardiac arrest and death.