People often think that a heart attack is the same thing as a cardiac arrest. This, however, is not true. In order to understand the difference between a heart attack and a cardiac arrest, it is first necessary to understand what happens in both of these processes.
The heart is a muscle, and like all muscles it requires an oxygen-rich blood supply. This is provided to the heart by coronary arteries. A heart attack occurs when there is a blockage of the coronary arteries. This is often caused by a blood clot. Such a blockage, if not quickly resolved, can cause parts of heart muscle to begin to die. (1-3)
A cardiac arrest is different to a heart attack. In a cardiac arrest the heart actually stops beating; whereas in a heart attack the heart normally continues to beat even though the blood supply to the heart is disrupted. (4, 5)
In addition to the physiological mechanism being different, the symptoms of a heart attack and a cardiac arrest also vary.
Symptoms of a heart attack include:
Symptoms of a cardiac arrest include:
The lack of pulse is caused by the heart actually stopping during a cardiac arrest. As a consequence of this, the organs of the body are deprived of blood – this can lead to death. (13)
The following warning signs may also occur in the period before a cardiac arrest:
Cardiac arrests have several potential causes. These include:
A cardiac arrest can also be caused by a heart attack. (5) In fact, according to the British Heart Foundation, the majority of cardiac arrests in the UK are caused by heart attacks. (18)
A heart attack itself involves a cut off in the blood supply to part of the heart muscle. If a large enough portion of the heart is affected, then the heart may stop beating, i.e. a cardiac arrest may occur. (14)
But what about heart attacks themselves? What causes them? Well, in contrast to cardiac arrests, heart attacks are generally caused by one main factor – coronary heart disease (CHD). (14) CHD is a condition that is generally caused by fatty deposits building up in the coronary arteries, which provide oxygenated blood to the heart. This is also known as atherosclerosis. (15 -17) Those most at risk of CHD include:
People with CHD may experience a heart attack if a plaque, (a raised patch on the artery wall) splits and causes a blood clot which in turn blocks the coronary artery. (17)
In summary, there is a difference between a heart attack and a cardiac arrest. A heart attack occurs when the blood supply to part of the heart stops and thus causes a section of the heart muscle to begin to die; whereas a cardiac arrest occurs when the heart stops beating as a whole. There are various symptoms of a heart attack. In contrast, the main symptoms of a cardiac arrest are unconsciousness, lack of breathing and no pulse. Finally, there are many different causes of a cardiac arrest; whereas the main cause of a heart attack is coronary heart disease.