Cardiac arrest also commonly referred to as sudden cardiac arrest (SCA), is a condition in which the heart abruptly and unexpectedly stops beating. This happens most times without warning. When it happens, blood stops flowing to the brain and other vital organs.
Cardiac arrest usually results from an electrical disturbance in your heart that disrupts its pumping action, stopping blood flow to the rest of your body. It is an emergency.
Signs and Symptoms
The signs and symptoms are immediate and drastic. They include:
Loss of consciousness
Abnormal or absent breathing
Shortness of breath
When the arrest occurs, the most obvious sign of its occurrence will be the lack of a palpable pulse in the person experiencing it (since the heart has ceased to contract, the usual indications of its contraction such as a pulse will no longer be detectable). Certain types of prompt intervention can often reverse a cardiac arrest, but without such intervention the event will almost always lead to death.
When sudden cardiac arrest occurs, your brain is the first part of your body to suffer because, unlike other organs, it doesn't have a reserve of oxygen-rich blood. It's completely dependent on an uninterrupted supply of blood. Reduced blood flow to your brain causes unconsciousness.
If your heart rhythm doesn't rapidly return to its normal rhythm, brain damage occurs and death results. If sudden cardiac arrest lasts more than 8 minutes, survival is rare.
What causes Cardiac Arrest?
The most common cause of cardiac arrest is coronary artery disease.
Less common causes include:
major blood loss
lack of oxygen
very low potassium
heart failure and
intense physical exercise.
A number of inherited disorders may also increase the risk including long QT syndrome.
If you experience an episode of sudden cardiac arrest without warning and survive, your doctor will want to investigate what caused the cardiac arrest. Identifying the underlying problem may help prevent future episodes of cardiac arrest.
Tests your doctor may recommend include:
Imaging tests such as Chest X-ray, Echocardiogram and Nuclear scan
Other tests that are often done include:
Electrical system (electrophysiological) testing and mapping
Coronary catheterization (angiogram)
Ejection fraction testing
Victims of cardiac arrest require immediate action for survival. This includes:
Immediate cardiopulmonary resuscitation (CPR) is critical to treating sudden cardiac arrest. By maintaining a flow of oxygen-rich blood to the body's vital organs, CPR can provide a vital link until more-advanced emergency care is available.
Once you arrive in the emergency room, the medical staff will work to stabilize your condition and treat a possible heart attack, heart failure or electrolyte imbalances. You may be given medications to stabilize your heart rhythm.
After you recover, your doctor will discuss with you or your family what additional tests you may need to determine the cause of the cardiac arrest. Your doctor will also discuss preventive treatment options with you to reduce your risk of another cardiac arrest.
Treatments may include:
Implantable cardioverter-defibrillator (ICD)
Coronary bypass surgery
Radiofrequency catheter ablation
Corrective heart surgery
You may require cardiac rehabilitation
Cardiac rehabilitation (rehab) teaches you how to be more active and make lifestyle changes that can lead to a stronger heart and better health. Cardiac rehab can help you feel better and reduce your risk of future heart problems.
In cardiac rehab, you work with a team of health professionals. Often the team includes a doctor, a nurse specialist, a dietician, an exercise therapist, and a physical therapist. The team designs a program just for you, based on your health and goals. Then they give you support to help you succeed.
If you have a heart problem or had surgery, you may be afraid to exercise. Or if you have never exercised, you may not know how to get started. Your cardiac rehab team will help you start slowly and work up to a level that is good for your heart.
Many hospitals and rehab centres offer cardiac rehab programs. You may be part of a cardiac rehab group, but each person will follow his or her own plan.
What happens in cardiac rehab?
In cardiac rehab, you will learn how to:
Manage your heart disease and problems such as high blood pressure and high cholesterol.
Eat a heart-healthy diet.
Reduce stress and depression.
Get back to work sooner and safely.
These lifestyle changes will also help prevent cardiac arrest or a reoccurrence.
Exercise is a big part of cardiac rehab. So before you get started, you will have a full checkup, which may include tests such as an electrocardiogram (EKG or ECG) and a "stress test" (exercise electrocardiogram). These tests show how well your heart is working. They will help your team design an exercise program that is safe for you.
At first your rehab team will keep a close watch on how exercise affects your heart. As you get stronger, you will learn how to check your own heart rate when you exercise. By the end of rehab, you will be ready to continue an exercise program on your own.
What are the benefits of cardiac rehab?
Starting cardiac rehab after a heart attack can lower your chance of dying from heart disease and can help you stay out of the hospital. It may reduce your need for medicine.
Cardiac rehab may also help you to:
Have better overall health.
Lose weight or keep weight off.
Feel less depressed and more hopeful.
Have more energy and feel better about yourself.
Changing old habits is hard. But in cardiac rehab, you get the support of experts who can help you make new healthy habits. And meeting other people who are in cardiac rehab can help you know that you're not alone.
Many who survive have significant disability. Survivors of cardiac arrest may show signs of brain damage.
The overall chance of survival among those who have cardiac arrest outside hospital is about 8%. For in hospital cardiac arrest survival to discharge is around 22% with many having a good neurological outcome.
Prognosis is typically assessed 72 hours or more after cardiac arrest. Rates of survival are better in those who someone saw collapse, got bystander CPR, or had either ventricular tachycardia or ventricular fibrillation when assessed. Survival among those with Vfib or Vtach is 15 to 23%. Women are more likely to survive cardiac arrest and leave hospital than men.
Because sudden cardiac arrest is so often linked with coronary artery disease, the same factors that put you at risk of coronary artery disease may also put you at risk of sudden cardiac arrest. These include:
A family history of coronary artery disease
High blood pressure
High blood cholesterol
A sedentary lifestyle
Drinking too much alcohol (more than two drinks a day)
Other factors that may increase your risk of sudden cardiac arrest include:
A previous episode of cardiac arrest or a family history of cardiac arrest
A previous heart attack
A personal or family history of other forms of heart disease, such as heart rhythm disorders, congenital heart defects, heart failure and cardiomyopathy
Age — the incidence of cardiac arrest increases with age
Being male — men are two to three times more likely to experience cardiac arrest than women
Using illegal drugs, such as cocaine or amphetamines
Nutritional imbalance, such as low potassium or magnesium levels
If someone has suddenly collapsed, is not breathing normally and is unresponsive, they are in cardiac arrest.
There is no time to lose. Even if you are untrained your actions can help.