Bleeding is the escape of blood from arteries, veins, or capillaries. Any uncontrolled bleeding, whether internal or external, is a life-threatening emergency since it can reduce the blood volume such that not enough oxygen reaches vital organs.

Asystole, sometimes called flatline, is the total absence of a heart rhythm or electrical activity in the heart. It can happen quite quickly if someone has a heart attack, and it sometimes follows bradycardia or tachycardia.

Because the brain and other vital organs live only for a few minutes after the heart stops it is important to be able to perform cardiopulmonary resuscitation (CPR) so that blood flow can be maintained. And of course, CPR is only performed on an unconscious person who has no circulation i.e. pulse.

This is also known as myocardial infarction and it is a situation where a coronary artery is totally blocked and the cardiac muscle is not getting enough blood. It is a very serious situation, one which can result in death very quickly. In fact, it is the number one cause of death in adults in North America.

A temporary decrease of blood flow to the brain can result in a fainting. Such a condition can be caused by standing up too fast, being tired, not eating properly, low blood pressure, and certain medications.

Bradycardia is defined as a very low heart rate caused by some kind of illness or malfunction of the heart's electrical rhythm. The average resting heart rate for an adult is about 60-70 beats per minute.

Blood pressure is simply defined as the amount of force blood exerts on the inside walls of blood vessels as it flows through them.

A stroke is a situation where there is poor blood circulation to parts of the brain. This can occur because an artery feeding the brain with blood and oxygen is either blocked or has ruptured (aneurysm) resulting in blood not getting through to the needed area.

Heart disease is any situation where the cardiac muscle (the heart) is not working properly. There are many reasons why this may occur, but for our purposes we will focus on what is commonly referred to as coronary artery disease. This is sometimes also called cardiovascular disease, arteriosclerosis, or atherosclerosis.

Cardiac arrest occurs when the heart stops beating or beats too irregularly or too weakly to circulate blood effectively. Breathing soon stops. Cardiac arrest is a life-threatening emergency because vital organs live only a few minutes without oxygen-rich blood.

Sudden cardiac arrest continues to be the number one cause of death in North America. In more than 80% of the cases, rapid defibrillation would have been beneficial. Furthermore, research shows that the maximum benefit occurs when the defibrillation is provided within 5 minutes of the point of collapse.

Tachycardia is defined as an increased heart rate usually over 100 beats per minute (bpm). The average resting heart rate is about 60-70 bpm. However, when we become more active our heart rate increases to meet the increased demand of muscles needing oxygen.

This is a condition where the coronary arteries are partially blocked and under physical or emotional stress the heart can't get enough blood and oxygen. As a result, the person experiences chest pain.