What Are the Warning Signs of Cardiac Arrest?

The most common cause of a cardiac arrest is an irregular heartbeat (arrhythmia) called ventricular fibrillation. Causes of ventricular fibrillation include:

• Heart problems
  • Heart attack
  • Coronary artery disease (atherosclerosis)
  • Heart failure
  • High blood pressure (hypertension)
  • Certain heart rhythm conditions, such as Long QT syndrome
• Physical stress
  • Intense physical activity
  • Very low blood levels of potassium or magnesium
  • Major blood loss
  • Severe lack of oxygen
    • Suffocation 
    • Choking
    • Drowning
• Allergic reaction
• Drug overdose
• Electrocution

Risk factors for developing cardiac arrest include:

• Older age
• Being male
• African American ethnicity, especially those who have underlying conditions such as diabetes, high blood pressure, heart failure, and chronic kidney disease
• A personal or family history of cardiac arrest or inherited disorders that make you prone to arrhythmias
• Drug or alcohol abuse

Cardiac arrest usually occurs suddenly and without warning and requires emergency treatment. It is rarely diagnosed with tests as it's happening, but is diagnosed after it occurs. 

People at high risk for cardiac arrest may be referred to a cardiologist, a doctor who specializes in diagnosing and treating heart diseases and conditions. 

Tests to help detect risk factors for cardiac arrest may include: 

• Electrocardiogram (EKG)
• Echocardiography (“echo”)
• Cardiac magnetic resonance imaging (MRI)
• Cardiac catheterization (“cardiac cath”)
• Electrophysiology study
• Blood tests to check levels of potassium, magnesium, and other chemicals in the blood that play a role in the heart's electrical signaling

Cardiac arrest is a medical emergency which is usually fatal if not treated immediately with a combination of cardio pulmonary resuscitation (CPR) and defibrillation. 

If you see someone you suspect may be in cardiac arrest, you can increase the person’s chances of survival by calling 911 immediately.

• CPR stands for CardioPulmonary Resuscitation, an emergency procedure that is a combination of chest compressions and artificial ventilation (breathing) used to save a person’s life when a person’s heart stops beating or breathing ceases. When performed right away, CPR can increase a person’s chances of survival after cardiac arrest.
• A machine called a defibrillator delivers an electric shock through the chest wall to correct the arrhythmia.
  • Immediate treatment with an automated external defibrillator (AED) can be life-saving. An AED is a portable device, often available in public locations for use by bystanders, that sends an electric shock to the heart, stopping an irregular heart rhythm (such as ventricular fibrillation), and allowing a normal rhythm to resume. Even without formal training, most people can effectively follow instructions on an AED while waiting for EMS to arrive. 

If a cardiac arrest occurs in a hospital, a clinical team (sometimes called a “crash team”) will be called to carry out CPR and defibrillation.

A person may be given medication to help reduce the risk of another cardiac arrest.

Once the cause of the cardiac arrest is determined, there may be additional treatment. 

• Coronary heart disease may require percutaneous coronary intervention, also known as coronary angioplasty, or coronary artery bypass grafting (CABG) to help restore blood flow through narrowed or blocked coronary arteries
• Implantation of an implantable cardioverter defibrillator (ICD), which uses electric pulses or shocks to help control dangerous arrhythmias