Introduction

Sudden cardiac arrest (SCA) is a condition where the heart abruptly ceases all activity due to an abnormal heart rhythm. This leads to a cessation of breathing and a loss of consciousness. If not treated immediately, SCA can result in death.

Urgent treatment for SCA involves cardiopulmonary resuscitation (CPR) and the application of electrical shocks to the heart using a device known as an automated external defibrillator (AED). With prompt and appropriate medical intervention, survival is possible.

It’s important to note that SCA differs from a heart attack. While a heart attack occurs when blood flow to a portion of the heart is obstructed, SCA is not caused by a blockage. However, a heart attack can trigger changes in the heart’s electrical system that may lead to SCA.

Indications
The signs of SCA are immediate and severe, including:

– Abrupt collapse
– Absence of pulse
– Cessation of breathing
– Loss of consciousness

In some instances, other symptoms may precede SCA, such as:

– Discomfort in the chest
– Difficulty breathing
– Weakness
– Rapid, fluttering, or forceful heartbeats, known as palpitations

However, SCA frequently occurs without any prior warning signs.

When to seek medical attention
When the heart stops functioning, the lack of oxygen-rich blood can swiftly lead to death or permanent brain damage.

Contact emergency services immediately if you experience:

– Pain or discomfort in the chest
– Sensation of a forceful heartbeat
– Accelerated or irregular heartbeats
– Unexplained wheezing
– Shortness of breath
– Fainting or near-fainting episodes
– Lightheadedness or dizziness

If you encounter someone who is unconscious and not breathing, call emergency services right away. Then, begin performing CPR. The American Heart Association advises performing CPR with forceful and rapid chest compressions. If available, use an AED.

CPR instructions
If the person isn’t breathing, perform CPR. Push hard and fast on the person’s chest, aiming for 100 to 120 compressions per minute. If you’re trained in CPR, check the airway and provide rescue breaths after every 30 compressions.

If you lack CPR training, focus solely on chest compressions. Ensure the chest fully rises between compressions. Continue this process until an AED becomes available or emergency responders arrive.

AEDs are accessible in many public spaces, including airports and shopping centers. They can also be purchased for home use. These devices come with voice instructions for operation and are programmed to deliver shocks only when appropriate.

Underlying causes
SCA is caused by a change in the heart’s electrical activity, which causes the heart to stop pumping blood. Consequently, no blood flows to the body.

Heart function
To comprehend SCA, it’s helpful to understand the heart’s signaling system.

Electrical signals in the heart regulate the rate and rhythm of heartbeats. Faulty or excess electrical signals can cause the heart to beat too quickly, too slowly, or in an uncoordinated manner. These changes in heartbeat are called arrhythmias. While some arrhythmias are brief and harmless, others can lead to SCA.

Heart conditions associated with SCA
The most common cause of SCA is an irregular heart rhythm called ventricular fibrillation. In this condition, rapid, erratic heart signals cause the lower heart chambers to quiver ineffectively instead of pumping blood. Certain heart conditions can increase the likelihood of experiencing this type of heart rhythm problem.

However, SCA can also occur in individuals with no known heart disease.

Heart conditions that may lead to SCA include:

– Coronary artery disease
– Heart attack
– Enlarged heart (cardiomyopathy)
– Heart valve disease
– Congenital heart defects
– Long QT syndrome (LQTS) and other heart signaling disorders

Risk factors
Factors that increase the risk of heart disease can also elevate the risk of SCA. These include:

– Family history of coronary artery disease
– Smoking
– High blood pressure
– High blood cholesterol
– Obesity
– Diabetes
– Sedentary lifestyle

Additional factors that may increase SCA risk include:

– Previous SCA episode or family history of SCA
– Previous heart attack
– Personal or family history of other heart conditions
– Advanced age
– Male gender
– Illegal drug use (e.g., cocaine or amphetamines)
– Low potassium or magnesium levels
– Obstructive sleep apnea
– Chronic kidney disease

Complications
During SCA, reduced blood flow to the brain can lead to complications such as brain damage and death if the heart rhythm isn’t promptly restored.

Prevention
Maintaining heart health may help prevent SCA. This can be achieved by:

– Eating a healthy diet
– Attending regular check-ups
– Avoiding tobacco use
– Undergoing heart disease screening
– Managing blood pressure and cholesterol

Genetic testing for long QT syndrome, a common cause of sudden cardiac death, is available. Consult your insurance provider regarding coverage. If you carry the long QT gene, your healthcare provider may recommend testing for other family members.

For individuals with a known risk of cardiac arrest, healthcare providers may suggest an implantable cardioverter-defibrillator (ICD), a heart device placed under the collarbone.

Consider purchasing an AED for home use, but discuss this with your healthcare provider first. While AEDs can help reset the heart’s rhythm during SCA, they can be expensive and may not always be covered by health insurance.