Cardiac arrest, is the cessation of normal circulation

Circulatory system

The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

 of the blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 due to failure of the heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 to contract effectively. Medical personnel can refer to an unexpected cardiac arrest as a sudden cardiac arrest or SCA.

A cardiac arrest is different from (but may be caused by) a heart attack

Myocardial infarction

Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

, where blood flow to the muscle of the heart is impaired.

Arrested blood circulation

Circulatory system

The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

 prevents delivery of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 to the body.