What is cardiac arrest

Sudden cardiac arrest is the sudden, unexpected loss of heart function, breathing and consciousness. Sudden cardiac arrest usually results from an electrical disturbance in your heart that disrupts its pumping action (ventricular arrhythmia), stopping blood flow to the rest of your body.

Sometimes other signs and symptoms precede sudden cardiac arrest. These may include fatigue, fainting, blackouts, dizziness, chest pain, shortness of breath, weakness, palpitations or vomiting. But sudden cardiac arrest often occurs with no warning.

• The time and mode of death are unexpected. Sudden cardiac arrest occurs instantly or shortly after symptoms appear.

Sudden cardiac arrest is different from a heart attack, which occurs when blood flow to a portion of the heart is blocked. However, a heart attack can sometimes trigger an electrical disturbance that leads to sudden cardiac arrest.

• Each year, more than 350,000 emergency medical services-assessed out-of-hospital cardiac arrests occur in the United States.
• The incidence of out-of-hospital sudden cardiac arrest in industrial countries is reported to be between 35.7 and 128.3 cases per 100,000, with a mean of 62 cases per year ¹. This translates into approximately 300,000 people in the United States and about the same number in Europe each year.

If you suspect the symptoms of a heart attack, dial your local emergency number immediately and ask for an ambulance.

Don’t worry if you have doubts. Paramedics would rather be called out to find an honest mistake has been made than be too late to save a person’s life.

Symptoms of a heart attack can include:

• chest pain – a sensation of pressure, tightness or squeezing in the center of your chest
• pain in other parts of the body – it can feel as if the pain is traveling from your chest to your arms (usually the left arm is affected, but it can affect both arms), jaw, neck, back and abdomen
• feeling lightheaded or dizzy
• sweating
• shortness of breath
• feeling sick (nausea) or being sick (vomiting)
• an overwhelming sense of anxiety (similar to having a panic attack)
• coughing or wheezing

Although the chest pain is often severe, some people may only experience minor pain, similar to indigestion. In some cases, there may not be any chest pain at all, especially in women, the elderly and people with diabetes.

It’s the overall pattern of symptoms that helps to determine whether you are having a heart attack.

If someone has had a heart attack, it’s important to rest while they wait for an ambulance, to avoid unnecessary strain on the heart.

If aspirin is easily available and the person who has had a heart attack isn’t allergic to it, slowly chew and then swallow an adult-sized tablet (300mg) while waiting for the ambulance.

The aspirin helps to thin the blood and restore the heart’s blood supply.

How to perform a Cardiopulmonary Resuscitation (CPR)

If the person’s breathing or heart stops, cardiopulmonary resuscitation (CPR) should be performed immediately.

Hands-only CPR

• Ensure the area is safe
• Check for hazards, such as electrical equipment or traffic.

To carry out a chest compression:

1. Place the heel of your hand on the breastbone at the center of the person’s chest. Place your other hand on top of your first hand and interlock your fingers.
2. Position yourself with your shoulders above your hands.
3. Using your body weight (not just your arms), press straight down by 5-6cm (2-2.5 inches) on their chest.
4. Keeping your hands on their chest, release the compression and allow the chest to return to its original position.
5. Repeat these compressions at a rate of 100 to 120 times per minute until an ambulance arrives or you become exhausted.

When you call for an ambulance, telephone systems now exist that can give basic life-saving instructions, including advice about CPR. These are now common and are easily accessible with mobile phones.

Cardiopulmonary Resuscitation (CPR) with rescue breaths

If you’ve been trained in CPR, including rescue breaths, and feel confident using your skills, you should give chest compressions with rescue breaths. If you’re not completely confident, attempt hands-only CPR instead (see above).

Adults

1. Place the heel of your hand on the centre of the person’s chest, then place the other hand on top and press down by 5-6cm (2-2.5 inches) at a steady rate of 100 to 120 compressions per minute.
2. After every 30 chest compressions, give two rescue breaths.
3. Tilt the casualty’s head gently and lift the chin up with two fingers. Pinch the person’s nose. Seal your mouth over their mouth and blow steadily and firmly into their mouth for about one second. Check that their chest rises. Give two rescue breaths.
4. Continue with cycles of 30 chest compressions and two rescue breaths until they begin to recover or emergency help arrives.

Children over one year old

1. Open the child’s airway by placing one hand on the child’s forehead and gently tilting their head back and lifting the chin. Remove any visible obstructions from the mouth and nose.
2. Pinch their nose. Seal your mouth over their mouth and blow steadily and firmly into their mouth, checking that their chest rises. Give five initial rescue breaths.
3. Place the heel of one hand on the center of their chest and push down by 5cm (about two inches), which is approximately one-third of the chest diameter.
4. The quality (depth) of chest compressions is very important. Use two hands if you can’t achieve a depth of 5cm using one hand.
5. After every 30 chest compressions at a rate of 100 to 120 per minute, give two breaths.
6. Continue with cycles of 30 chest compressions and two rescue breaths until they begin to recover or emergency help arrives.

Infants under one year old

1. Open the infant’s airway by placing one hand on their forehead and gently tilting the head back and lifting the chin. Remove any visible obstructions from the mouth and nose.
2. Place your mouth over the mouth and nose of the infant and blow steadily and firmly into their mouth, checking that their chest rises. Give five initial rescue breaths.
3. Place two fingers in the middle of the chest and push down by 4cm (about 1.5 inches), which is approximately one-third of the chest diameter. The quality (depth) of chest compressions is very important. Use the heel of one hand if you can’t achieve a depth of 4cm using the tips of two fingers.
4. After 30 chest compressions at a rate of 100 to 120 per minute, give two rescue breaths.
5. Continue with cycles of 30 chest compressions and two rescue breaths until they begin to recover or emergency help arrives.

Cardiac arrest vs Heart attack

People often use the term “heart attack” mistakenly used to describe cardiac arrest. Heart attack and Sudden Cardiac Arrest are not the same.

While a heart attack may cause cardiac arrest and sudden death, the terms don’t mean the same thing. Heart attacks are caused by blood supply to the heart being suddenly interrupted due to a blockage in the coronary arteries that stops blood flow to the heart. A heart attack (or myocardial infarction) refers to death of heart muscle tissue due to the loss of blood supply, not necessarily resulting in the death of the heart attack patient.

Cardiac arrest is caused when the heart’s electrical system malfunctions. In cardiac arrest death results when the heart suddenly stops working properly. This may be caused by abnormal, or irregular, heart rhythms (called arrhythmias).

Difference between heart attack and cardiac arrest

• A heart attack is when blood flow to the heart is blocked, and sudden cardiac arrest is when the heart malfunctions and suddenly stops beating unexpectedly.
• A heart attack is a “circulation” problem and sudden cardiac arrest is an “electrical” problem.

A common arrhythmia in cardiac arrest is ventricular fibrillation. This is when the heart’s lower chambers suddenly start beating chaotically and don’t pump blood. Death occurs within minutes after the heart stops. Cardiac arrest may be reversed if CPR (cardiopulmonary resuscitation) is performed and a defibrillator is used to shock the heart and restore a normal heart rhythm within a few minutes.

These two distinct heart conditions are linked. Sudden cardiac arrest can occur after a heart attack, or during recovery. Heart attacks increase the risk for sudden cardiac arrest. Most heart attacks do not lead to sudden cardiac arrest. But when sudden cardiac arrest occurs, heart attack is a common cause. Other heart conditions may also disrupt the heart’s rhythm and lead to sudden cardiac arrest. These include a thickened heart muscle (cardiomyopathy), heart failure, arrhythmias, particularly ventricular fibrillation, and long Q-T syndrome.

What is a heart attack?

A heart attack occurs when a blocked artery prevents oxygen-rich blood from reaching a section of the heart. If the blocked artery is not reopened quickly, the part of the heart normally nourished by that artery begins to die. Without treatment, the heart muscles will experience irreversible damage. The longer a person goes without treatment, the greater the damage. Symptoms of a heart attack may be immediate and intense. More often, though, symptoms start slowly and persist for hours, days or weeks before a heart attack. Unlike with sudden cardiac arrest, the heart usually does not stop beating during a heart attack. The heart attack symptoms in women can be different than men.

If a large portion of the heart is damaged in this way, the heart stops beating (known as a cardiac arrest), resulting in death.

Coronary heart disease (coronary artery disease) is the leading cause of heart attacks. Coronary heart disease (coronary artery disease) is a condition in which the coronary arteries (the major blood vessels that supply the heart with blood) get clogged up with deposits of cholesterol (atheroma). These deposits are called plaques.

Before a heart attack, one of the plaques ruptures (bursts), causing a blood clot to develop at the site of the rupture. The clot may block the supply of blood to the heart, triggering a heart attack.

Your risk of developing coronary artery disease is increased by:

• smoking
• a high-fat diet
• diabetes
• high cholesterol
• high blood pressure
• being overweight or obese.

What to do for Heart Attack

Even if you’re not sure it’s a heart attack, call your emergency response number. Every minute matters! It’s best to call emergency medical services (EMS) to get to the emergency room right away. Emergency medical services staff can begin treatment when they arrive — up to an hour sooner than if someone gets to the hospital by car. Emergency medical services staff are also trained to revive someone whose heart has stopped. Patients with chest pain who arrive by ambulance usually receive faster treatment at the hospital, too.

What is cardiac arrest?

Sudden cardiac arrest occurs suddenly and often without warning. It is triggered by an electrical malfunction in the heart that causes an irregular heartbeat (arrhythmia). With its pumping action disrupted, the heart cannot pump blood to the brain, lungs and other organs. Seconds later, a person loses consciousness and has no pulse. Death occurs within minutes if the victim does not receive treatment.

What to do in Sudden Cardiac Arrest

Cardiac arrest is reversible in most victims if it’s treated within a few minutes. Begin CPR immediately and continue until professional emergency medical services arrive. If two people are available to help, one should begin CPR immediately while the other calls the local emergency number and finds a defibrillator.

Cardiac arrest causes

Cardiac arrest may be caused by almost any known heart condition. Most cardiac arrests occur when the diseased heart’s electrical system malfunctions, producing an abnormal rhythm such as ventricular tachycardia or ventricular fibrillation. Some cardiac arrests are caused by extreme slowing of the heart’s rhythm.

All of these events are called life-threatening arrhythmias.

Below is a list of other causes of cardiac arrest:

• Scarring from a prior heart attack or other causes: A heart that’s scarred or enlarged from any cause is prone to develop life-threatening ventricular arrhythmias. The first six months after a heart attack is a particularly high-risk period for sudden cardiac arrest in patients with atherosclerotic heart disease.
• A thickened heart muscle (cardiomyopathy) from any cause (typically high blood pressure or valvular heart disease) — especially if you also have heart failure — can make you more prone to sudden cardiac arrest.
• Heart medications: Under certain conditions, various heart medications can set the stage for arrhythmias that cause sudden cardiac arrest. Paradoxically, antiarrhythmic drugs used to treat arrhythmias can sometimes produce lethal ventricular arrhythmias even at normally prescribed doses. This is called a “proarrhythmic” effect. Regardless of whether there’s organic heart disease, significant changes in blood levels of potassium and magnesium (from using diuretics, for example) also can cause life-threatening arrhythmias and cardiac arrest.
• Electrical abnormalities: Certain electrical abnormalities such as Wolff-Parkinson-White syndrome and Long QT syndrome may cause sudden cardiac arrest in children and young people.
• Blood vessel abnormalities: Less often, inborn blood vessel abnormalities, particularly in the coronary arteries and aorta, may be present in young sudden death victims. Adrenaline released during intense physical or athletic activity often acts as a trigger for sudden cardiac arrest when these abnormalities are present.
• Recreational drug use: In people without organic heart disease, recreational drug use is a cause of sudden cardiac arrest.

Cardiac arrest signs and symptoms

• Cardiac arrest strikes immediately and without warning!

Here are the signs:

• Sudden loss of responsiveness (no response to tapping on shoulders).
• No response to tapping on shoulders.
• Does nothing when you ask if he’s OK.
• No normal breathing
• Victim is not breathing or is only gasping.

If you suspect someone is suffering from cardiac arrest:

• Tap and shout
  • Check if the person responds. Tap him and shout, “Are you OK?” If he doesn’t move, speak, blink, or otherwise react, then he is not responding.
• Yell for help
  • Tell someone to call your emergency response number and get an Automated External Defibrillator (if one is available).
  • If you are alone with an adult who has these signs of cardiac arrest, call your local emergency number and get an Automated External Defibrillator (if one is available).
• Check breathing:
  • If the person isn’t breathing or is only gasping, give CPR.
• Giving CPR: Push hard and fast
  • Push down at least 2 inches at a rate of 100 to 120 pushes a minute in the center of the chest, allowing the chest to come back up to its normal position after each push.
• Use an Automated External Defibrillator as soon as it arrives by turning it on and following the prompt.
• Keep pushing until the person starts to breathe or move or someone with more advanced training takes over.

Prognosis for Cardiac Arrest Survivors

The majority of cardiac arrest survivors have some degree of brain injury and impaired consciousness. Some remain in a persistent vegetative state. Determining the survivor’s prognosis and making the decision to treat or to withdraw care is complicated and based on many variables (many of which have not been thoroughly studied).

Factors before cardiac arrest:

• Age
• Ethnicity
• Poor health including diabetes, cancer, infection, kidney disease and stroke

Factors during cardiac arrest:

• Time between collapse and start of CPR/defibrillation
• Quality of CPR/defibrillation
• Whether survivor had any neurological function during or immediately after CPR

Factors after cardiac arrest and resuscitation:

• Neurological function: Generally, poor function equals poor prognosis but could be complicated by medical instability and treatments. Some patients suffer a stroke after a cardiac arrest.
• Neurophysiologic function: tests include somatosensory evoked potentials (SSEP) and electroencephalogram (EEG).
• Neuroimaging and monitoring: to determine structural brain injury — such as cranial CT, MRI, magnetic resonance spectroscopy, positron emission tomography (PET) — mostly to exclude hemorrhage or stroke.
• Biochemistry: from blood or cerebrospinal fluid
• Whether therapeutic hypothermia (intentionally lowering the patient’s body temperature) was used.

1. Becker LB, Smith DW, Rhodes KV. Incidence of cardiac arrest: a neglected factor in evaluating survival rates. Ann Emerg Med. 1993 Jan. 22 (1):86-91.[↩]