As the name suggests, sudden cardiac death (SCD) is death from a cardiac cause within a short span of time i.e. within an hour of onset of symptoms. As the term is generally applied to the sudden, unexpected and natural event of death, it is commonly used in the domains of public health.

Such a death is often a consequence of an unattended heart abnormality which if attended on time could have prevented death in some, if not all, cases. These sudden deaths usually occur during exertion (like a sporting event) although cases in which death occurs during sleep are not unknown.


Coronary artery disease

It is the most common cause of SCD in young individuals aged between 30 to 40 years. In such cases, a segment or whole of a major coronary artery (vessels supplying blood to the heart muscles) is blocked and thereby hampers the blood supply to the heart muscles. This decreases the contractility of the heart and disturbs the normal cardiac cycle. It is important to note that even a small irregularity in one part of the cardiac cycle can disturb the contractility of the whole heart. This is so because blood pumped out by one chamber of heart is transferred to the next chamber which further pumps it forward and hence each chamber of heart is dependent on other for its normal functioning.

In view of above, a small clot in the coronary artery can sometimes be sufficient enough to cause sudden death.

Left ventricular hypertrophy

In this condition, muscles of left ventricles thicken and are unable to pump the blood effectively.

The left ventricle is one of the four chambers of the heart and is responsible for ejecting the oxygenated blood into the circulatory system. In other words, it is the gateway between the blood in heart chambers and that in the vessels. So any increased pressure of blood in the blood vessels (called as high blood pressure or hypertension) is directly transferred to the Left ventricle. To compensate this, left ventricle tries to get rid of this extra pressure by pushing the blood back into the blood vessels. Hence there is an extra load on the heart muscles which thickens as a compensatory response. This continuous effort by heart muscles led to their fatigue and hence reduces their efficiency to pump the blood.

Ventricular fibrillation

This is the most common mechanism of sudden cardiac death. Both the above-mentioned conditions led to Ventricular fibrillation.

In this condition ventricular muscles contract in an irregular fashion rather than in the synchronized manner so that blood is not pumped in the blood vessels and all the organs of the body are devoid of their supply of oxygenated blood. This lack of blood in the vessels leads to a sudden drastic drop in the blood pressure and consequently death.

Red flags to watch for in patients at risk

Sudden Cardiac Death

Sudden loss of consciousness: Sudden fainting during physical exertion points to the fact that heart is not functioning to an optimum level to maintain the blood supply of the body organs. In such cases, the patient should be screened with the help of appropriate tests and needful should be done.

The family history of sudden cardiac death: Any sudden cardiac death in the family suggests the predisposition to such an event and warrants proper screening.

Patients with high risk of SCD should take appropriate steps with the help of their doctor. They can also consider purchasing an automated external defibrillator (AED) for emergency use if advised by the doctor. Family members or people living with a high-risk person should train themselves in cardio pulmonary resuscitation (it is a set of manual techniques aimed at reviving a person whose breathing or heart has stopped)

Prevention of sudden cardiac death

There is no sure way to predict or foresee sudden cardiac death. There are many complex predisposing factors that interplay that cause death in such cases so taking appropriate steps to reduce the risk is imperative. The steps that one can take to reduce the risk are:

  • Regular heart check-ups
  • Cessation of smoking
  • Consumption of alcohol in moderate amounts
  • Healthy diet
  • Regular exercise
  • Appropriate management of Diabetes and hypertension.

To conclude, we would like to emphasize that although sudden cardiac death can’t be foreseen by a doctor or the patient in every case but a substantial number of fatalities can be prevented by a healthy lifestyle and keen observation.

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