Sudden Cardiac Death Causes

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Sudden cardiac death usually occurs due to changes in the heart that alter the electrical signaling to cause arrhythmias. The irregular heartbeat increases the risk of dangerous circumstances and sudden cardiac death.

Ventricular Fibrillation

The most common cause of sudden cardiac arrest is ventricular fibrillation, which is a type of arrhythmia. This involves abnormal function of the ventricles of the heart, causing to them beating faster than usual and with great irregularity. As a result, blood is pumped from the heart and around the body less effectively, which can lead to fatal outcomes such as sudden cardiac death.

Coronary Heart Disease

Coronary heart disease (CHD) is a health condition that involves the build-up of plaque in the coronary arteries, which can narrow the arteries and reduce the supply of oxygen to the cardiac muscles.

In some cases, the plaque can rupture and a blood clot can form, obstructing the flow of blood and blocking the supply of oxygen to the heart muscle. As a result, a heart attack may occur and the cardiac muscle cells may be damaged or die, which are replaced with scar tissue that can disrupt the electrical signals within the heart. These changes can increase the risk of arrhythmias and sudden cardiac death.

Physical Stress

In some circumstances, significant physical stress can cause changes in the electrical signaling within the heart muscle and lead to increased risk of sudden cardiac death. For example, the adrenaline hormone is released during intense physical activity, which can trigger changes in the heart muscle and cause cardiovascular events.

Additionally, certain extreme physical circumstances may lead to sudden cardiac death. This includes extremely low levels of potassium or magnesium salts in the body, as they play an essential part in the electrical signaling within the heart. Severe blood loss or lack of oxygen may also contribute to the cause.

Inherited Disorders

As it has been observed that arrhythmias tend to run in families, it has been suggested that there may be particular gene defects that may be inherited from parents that places and individual at higher risk of experiencing sudden cardiac death.

For example, long QT syndrome is an inherited disorder that involves changes in the electrical activity of the heart and increases the risk of arrhythmias for an individual. As a result, patients that have inherited this condition are more likely to suffer from sudden cardiac death.

Heart Remodeling

Changes to the electrical signaling within the heart may also come about as a result of altered physical size or structure of the heart.

For example, hypertension or cardiovascular disease can cause remodeling and enlargement of the heart to cope with the increased demands on the cardiovascular system. This enlargement can interfere with the electrical signaling and increase the risk of sudden cardiac death.

Heart Infections

In some cases, infections that affect the heart tissue can cause structure changes to the area, including scar tissue, which can interfere with the normal electrical signals. Once again, this can lead to an irregular heartbeat and has the potential to cause sudden cardiac death.


Further Reading

Last Updated: Aug 23, 2023

Susan Chow

Written by

Susan Chow

Susan holds a Ph.D in cell and molecular biology from Dartmouth College in the United States and is also a certified editor in the life sciences (ELS). She worked in a diabetes research lab for many years before becoming a medical and scientific writer. Susan loves to write about all aspects of science and medicine but is particularly passionate about sharing advances in cancer therapies. Outside of work, Susan enjoys reading, spending time at the lake, and watching her sons play sports.


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