Heart Attacks and Strokes
The heart muscle needs a constant supply of oxygen rich blood. Oxygen is delivered to the heart muscle by a network of blood vessels on it's outer surface called coronary arteries. Any blockage of blood flow to any part of the heart muscle creates a life-threatening medical emergency called a heart attack.
Brain tissue also needs a constant supply of oxygen rich blood. If there is any blockage in one of the blood vessels that supplies the brain it causes a life threatening emergency called a stroke.
As a person ages, fatty deposits accumulate in their blood vessels making it more difficult for blood to circulate through them. These deposits collect throughout the body, but are most dangerous in the heart muscle and the brain. Some of the factors that affect how quickly these deposits form are things like smoking, diet and exercise, and age and family history. Living a healthy lifestyle is the best way to reduce your risk of developing serious heart disease.
Your blood-pressure and blood cholesterol can be early indicators of developing heart disease. As your arteries become more restricted, your heart has to pump harder to force blood past the obstructions causing your blood-pressure to be high. Cholesterol is a type of fat in your blood and is most responsible for forming deposits in your blood vessels. You should have your blood-pressure and blood cholesterol checked regularly throughout your life, especially if your family has a history of heart disease.
Heart disease is the chief cause of heart attacks and strokes.
A heart attack occurs when the blood supply to a part of the heart is significantly reduced or stopped. This is typically caused by the rupture of a hardened fatty deposit in one of the coronary arteries which causes the formation of a blood clot that fully or partially blocks the blood supply to part of the heart. When this happens a part of the heart muscle goes into distress and starts to die. The longer a patient's heart is in distress, the more of the heart's muscle tissue dies.
Many people mistakenly think that a 'heart attack' is the same as 'cardiac arrest'. The heart doesn't necessarily stop when a person has a heart attack.
Conscious Heart AttackSometimes a person having a heart attack may be awake and only have symptoms of being sick. Even though the heart is in distress, it may be able to keep pumping. This condition can go on for hours or even days, but the longer it goes un-treated, the more damage there is to the person's heart.
Signs of a person having a conscious heart attack:
- Chest pain or discomfort. People describe it as "a huge weight on my chest" or "my chest feels like it is being squeezed in a vise".
NOTE: many people, especially women, feel only mild discomfort or no pain at all. Just because a person doesn't have chest pain doesn't necessarily mean they aren't having a heart attack.
- Pale sweaty skin that feels cool to the touch
- Shortness of breath. Many people say "I feel like I can't breathe" or "I can't seem to catch my breath".
- Indigestion or heart burn.
- Nausea, vomiting. Sometimes causes people to mistake a heart attack for the flu.
- Anxiety, fear of dying, and sometimes denial that they have a serious condition.
Sometimes a person's heart will stop pumping immediately. This is called "sudden cardiac arrest". When a person's heart stops, they will go unconscious and stop breathing within seconds. A person whose heart has stopped needs CPR within minutes to have a chance for recovery.
CPR, or 'cardio-pulmonary resuscitation' is the combination of compressing a person's chest to circulate blood, and breathing into their lungs to provide oxygen.
Why CPR is Important
All of the body's tissues need a continuous supply of blood carrying oxygen from the lungs. When a person's heart stops, their body tissues stop getting supplied with oxygen and they go into distress. The brain is especially affected by a lack of oxygen and it will actually start to die after just a few minutes with no oxygen. If a person's heart stops, someone has to start CPR within just a couple of minutes or even if they recover they will likely have permanent brain damage.
The rest of the body's tissues are also affected by a lack of oxygen. After several minutes without oxygen body tissues start to shut down. The longer a person goes without CPR, the less likely it is that they will be able to be revived.
If you live in a city or somewhere with nearby emergency medical services, the Fire department or an ambulance will be able to respond in about 3 to 5 minutes from the time they are called. But even in the 'best-case' scenario where someone calls 911 right-away when a person collapses, 3 to 5 minutes is not fast enough to prevent some brain damage. In reality, it is usually at least 3 to 5 minutes before anybody even calls 911.
Recent research shows that the most important factor for survival of an out of hospital heart attack is whether someone gives CPR right away. If no-one at the scene starts CPR for a person within minutes of their collapse, their chances of survival will be very low regardless of anything that firefighters, paramedics, or doctors do.
How CPR Works
CPR is the combination of chest-compressions and rescue breaths. The most important thing in the first few minutes after a person's heart stops is to give chest-compressions.
The heart works the same way as a foot pump for an air mattress. Each chamber has two one-way valves. One valve only lets blood into the chamber, and the other valve only lets blood out of the chamber. When the heart beats, it squeezes all the blood out of the chamber through the out-valve. In between beats the heart relaxes, allowing it to fill up with blood again through the in-valve.
When you compress the chest you are compressing the heart between the breast-bone and the spine, squeezing the blood out through the out-valve. Then when you relax the chest, the heart is allowed to fill up with blood again through the in-valve. When you do chest-compressions you are using the heart to pump blood the same way it does when it is beating on it's own.
To circulate the blood most effectively you should:
Push hard, Push fast, and Don't stopPush Hard
For adults (anybody 8 years or older) you should compress the chest at least 5 cm (2 inches) in a smooth continuous motion. Then you need to release the chest fully to allow the heart to fill up with blood again.
Do chest compressions at a rate of at least 100 compressions per minute. To go the right speed, get the beat of "Stayin' Alive" by the Bee Gees in your head. The beat of this song is exactly 100 beats per minute.
When you start chest compressions it takes a few seconds for pressure to build up before blood starts actually 'flowing'. Every time you stop compressions the pressure falls back to zero, so that when you start again it will take a few seconds of compressions before blood starts flowing. You should stop chest compressions only to give rescue breaths.
When a person's heart stops most of the body's systems shut down and go into a sort of "survival mode", and most of the blood circulation is shunted to the body core and the brain. When this happens the body tissues only use about 25% of the oxygen they normally use which means that there is a supply of oxygen in the blood sitting in the cardiovascular system that isn't being used. By circulating that blood up into the brain you can supply enough oxygen to maintain it. This "reserve" supply of oxygen only lasts a couple of minutes so you need to give rescue breaths to supply more oxygen into the lungs.
Rescue breathing is blowing your breath into a person's lungs to give them oxygen. When blood is circulated through the lungs it picks up the oxygen and then carries it to the brain and heart muscle. Even though your own body uses some of the oxygen in the air, there is still enough oxygen in the breath you blow out to maintain a person's body tissues.
It has become apparent that in our culture most people are uncomfortable or unwilling to give mouth-to-mouth rescue breathing. Although the actual risk of disease transmission is quite low, it is perceived as "yucky". Note that breathing through a cloth, or poking a hole in a plastic bag gives NO protection from disease transmission and will probably just get in the way. If you are unwilling to give mouth-to-mouth breathing, just give continuous chest-compressions.
It is important to know that CPR does NOT work in reality the same way that it works on TV or in the movies!
On TV two or three really good chest compressions are enough for a person's heart to start again, and sometimes they even start coughing. In reality, it never happens like that.
- CPR (typically) DOES NOT re-start a person's heart.
- CPR DOES maintain a person's body tissues until their heart can be re-started by advanced medical treatment.
It is normal for people who have a heart attack where their heart stops to not wake up for several days. In fact, the standard practice now in hospitals is to keep the person unconscious and cool their body to help their recovery.
The other important thing to know is that giving CPR is NOT a guarantee that a person will survive. The reality is that most people whose hearts stop don't survive, even if someone gives CPR right away.
But really, the most important thing to know is that giving CPR can dramatically improve a person's chances of survival. In fact bystander CPR has been shown to DOUBLE a person's chance of survival. Any improvement to survival rates translates directly to lives saved. There is no other part of our medical system that could come close to that level of improvement.
Firefighters, paramedics, and doctors are already giving the best treatment possible to cardiac arrest patients. The biggest potential for improving survival rates is for people like you to give CPR as quickly as possible when a person has a cardiac arrest.
Free online risk assessment
Visit The Heart & Stroke Foundation of B.C. and Yukon for more information on heart disease. You can also take free online risk assessments for heart disease and get a personalized action plan for healthy living.