Sudden cardiac arrest (SCA) refers to the abrupt cessation of all heart activity caused by an irregular heart rhythm. This leads to the cessation of breathing and loss of consciousness. Without prompt intervention, sudden cardiac arrest can quickly lead to death.

Emergency treatment for sudden cardiac arrest involves performing cardiopulmonary resuscitation (CPR) and administering electrical shocks to the heart using a device known as an automated external defibrillator (AED). Again, survival is possible with swift and appropriate medical care. 

An SCA is Not A Heart Attack

Don't confuse an SCA with a heart attack. A heart attack occurs when blood flow to a specific part of the heart is blocked which causes chest pain and shortness of breath. A blockage of this type does not trigger an SCA. 

So, a heart attack can lead to an SCA but an SCA will not cause a heart attack.

Instead, the heart's electrical system goes haywire because of a change in the heart's electrical activity. This is called an arrhythmia. An arrhythmia may happen because of plaque buildup or high cholesterol, both of which also may cause a heart attack.

A reduction of blood to the heart, which frequently occurs from coronary artery disease can also lead to ventricular fibrillation (an irregular heartbeat), which causes an SCA.

SCA Symptoms

Again, the symptoms of sudden cardiac arrest are immediate and severe, and may include:

  • Sudden collapse
  • An absence of a pulse
  • Cessation of breathing, and 
  • A loss of consciousness. 

In some cases, there may be preceding symptoms such as chest discomfort, difficulties with breathing, weakness, or palpitations (a fast, fluttering, or pounding heart). However, sudden cardiac arrest can also occur--and often does--without any warning signs. 

When to Call 911

If you experience any of the following symptoms, you need to seek immediate medical attention right away by calling 911:

  • Chest pain or discomfort
  • A pounding heartbeat
  • Rapid or irregular heartbeats
  • Unexplained wheezing
  • Shortness of breath
  • Lightheadedness or dizziness
  • Near-fainting spells

Should you encounter an individual who is unconscious and not breathing, it is essential to immediately call 911 or local emergency services and initiate CPR. The American Heart Association recommends performing CPR with firm and rapid chest compressions.

If available, utilize an automated external defibrillator (AED) to shock the heart and regain a heartbeat until emergency help arrives.

Basic CPR Steps

To perform basic CPR, follow these steps:

1. Begin CPR if the person is not breathing. 

2. Apply firm and rapid chest compressions at a rate of approximately 100 to 120 compressions per minute. 

3. Check the person's airway and deliver rescue breaths after every 30 compressions. 

4. Allow the chest to fully rise between compressions. Maintain this procedure until an AED becomes accessible or emergency medical professionals arrive. 

In-Pulse CPR Features Portable AEDs Online

Portable AEDs can be found in various public locations, such as airports and shopping malls. They are also available for purchase for home use. 

You can buy the devices online through In-Pulse CPR. AEDs are equipped with clear voice instructions to guide users through the process. These devices are programmed to administer a shock only when required.

The Underlying Cause for Heart Attacks and SCAs: Coronary Artery Disease

Coronary artery disease (CAD) is the main reason someone may experience a heart attack or an SCA. In fact, CAD is the most common reason for sudden cardiac death (SCD). It accounts for 80% of the cases. 

Typically, young people, 35 and younger, succumb to an SCD due to a fatal arrhythmia. In patients aged from birth to 13 years old, the primary cause of an SCA or SCD is a congenital abnormality. 

SDA in patients 14 to 24 years old is frequently attributed to hypertrophic cardiomyopathy (HCM) or arrhythmogenic right ventricular cardiomyopathy (ARVC).

Epidemiology

The median age of most patients who experience an SCAs is between 66 and 68 years of age, with more males than females experiencing these events.

When Most SCDs Occur

Most SCDs happen from 6:00 am to 12:00 noon, with a smaller peak occurrence happening in the late afternoon. Incidences of these fatalities are more likely to happen on Monday.

After a myocardial infarction (heart attack), the risk of a sudden cardiac death (SCD) is highest during the first few months. During this time, an SCD may result from a fatal tachyarrhythmia (fast heartbeat), a myocardial rupture, or another heart attack. 

While irregular heart rhythm problems such as ventricular fibrillation (VF) or ventricular tachycardia (VT) were first thought to lead to out-of-hospital cardiac arrest (OHCA), recent studies indicate that pulseless, electrical activity (PEA) or asystole are more frequent causes.

Asystole, known as flatlining, is defined as a stoppage of the heart's electrical and mechanical activity. It results from the deterioration of initial ventricular rhythms - ventricular fibrillation (V-fib) or pulseless ventricular tachycardia (V-tach).

The Survival Rate

The current out-of-hospital survival rate for people who have SCAs is only around 7%. Therefore, it's imperative that everyone takes the time to learn CPR. Doing so can make a big impact on SCA survival rates.

Learning Basic Life Support (BLS) CPR and AED

The best way to learn CPR is on-site. While CPR training programs exist on the Internet, it's best to schedule training in a classroom setting at work or at a community facility. That way, you can experience, hands-on, how to properly give CPR as well as operate an AED.

Although an AED comes with instructions, it's best to familiarize yourself with CPR and the operation of an AED to be fully prepared in case of an emergency.

Author: Donna Ryan 

Donna Ryan is a health and fitness writer who lives in Tucson, AZ. She writes on a vast range of health topics, including health conditions, fitness and self-improvement.