Sudden Cardiac Arrest Causes
Medical Author: Benjamin C. Wedro, MD, FAAEM, FACEP
Medical Editors: Melissa Conrad Stöppler, MD
What is Sudden Cardiac Arrest?
On June 25, 2009, paramedics were called to the home of
Michael Jackson responding to calls that he wasn't breathing. They found him in
cardiac arrest and started CPR. He was transported to UCLA medical center were
numerous attempts to restart his heart failed and he was pronounced dead.
Every day, calls come into the 911 emergency dispatch centers across the
country with frantic voices crying for help. A person can't be wakened,
breathing has stopped, and a pulse can't be felt. Cardiac arrest, the failure of
the heart's electrical conducting system to generate a heart beat, marks the end
of life. No matter what the cause, death happens when the heart stops beating.
The heart is an electrical pump. The mechanical pumping action that
circulates blood requires an organized electrical system to get the heart muscle to
squeeze. There are many reasons for the electrical activity to fail, and it's
almost always due to irritable heart muscle cells that, in effect, cause a short
Sudden Cardiac Arrest Causes
Examples of some of the causes of sudden cardiac arrest include:
- The electrical irritability may be due to a
heart attack (myocardial infarction), in which a blood
vessel in the heart is blocked and prevents
oxygen-rich blood from getting to heart cells. This can cause a fatal heart
rhythm called ventricular fibrillation characterized by electrical activity that
is so chaotic, that the heart just jiggles and does not beat effectively to pump
- The same irritability may be caused by
abnormally high potassium
levels in the blood stream.
- Abnormal heart rhythms may be a complication of
accidental poisoning or
drug overdoses, in which the drug is directly toxic to
the heart or else potentially blocks oxygen from getting into the blood stream.
- Carbon monoxide and
attach tightly to red blood cells, preventing them from accessing oxygen. Not
only does the smoke of a house fire contain carbon monoxide, but the chemicals
in drapes, rugs, and furniture release cyanide.
- Drugs such as cocaine
and methamphetamine act like adrenaline
in the body and can put the heart's electrical system into a deadly
- Downer drugs (depressant drugs that diminish the function of the central
nervous system) such as narcotics [for example pain medication such as
meperidine (Demerol)] and alcohol can depress brain
function and it "forgets" to tell the body breathe,
which is detrimental to the heart.
- Sudden cardiac arrest occurs in young athletes with previously undetected heart valve
- It occurs in SIDS, sudden infant death syndrome.
- Sudden cardiac arrest can occur in
people at the end of a long healthy life when they die quietly in their
Preventing Death in Cases of Sudden Cardiac Arrest