a woman using a defibrillator

What Conditions Require Defibrillators?

Your heart, the organ responsible for circulating blood and oxygen to all of your vital organs, is like a machine that is powered by electricity. Unfortunately, sometimes machines break down.

When your car battery dies, you need jumper cables and someone to help you jumpstart it. Similarly but more seriously, when a heart stops beating, it must be jump-started with electrical shocks in order to pump again. Defibrillators are the tools that deliver those shocks. Defibrillators can save lives. Below are the most common conditions that necessitate the use of a defibrillator:

Sudden Cardiac Arrest (SCA)

According to the American Heart Association, sudden cardiac arrest differs from a heart attack, in which a part of the heart stops beating. During a heart attack, a person can still breathe and perhaps even talk; some amount of blood is still being pumped throughout the body. When SCA occurs, the entire heart stops or is rendered ineffective in pumping a sufficient amount of blood to supply the organs. A person will stop breathing and may turn pale or a blueish hue, losing consciousness and probably fall to the ground. Some victims will experience seizures. Death can occur within minutes without defibrillation, cardiopulmonary resuscitation (CPR), and medical assistance.

According to the Sudden Cardiac Arrest Coalition (SCAC), 424,000 people in the U.S. experience sudden cardiac arrest each year, and nine out of ten victims die. The Coalition suggests that someone dies of SCA every two minutes, the small amount of time it may take you to read this article. Approximately two-thirds of SCA deaths occur without any prior knowledge of a heart condition.

Ventricular Arrythmias

Ventricular arrhythmias are the most common cause for SCA. Your heart is divided into four chambers that pump your blood continually: two upper chambers—the atria, and two lower chambers—the ventricles. Like most machines that have constant moving parts, there is a risk of mistiming and getting "out of sync." Sometimes a mistake in the process is barely noticeable, or if it is, the problem can be resolved on its own or by recalibrating the machine. It is the same with your heart.

Arrhythmias are irregular heartbeats, and not all arrythmias are fatal. Many do not affect everyday life, and others are treatable with medication, implantable medical devices such as pacemakers or implantable cardioverter defibrillators, or surgical procedures, all which function as calibration tools.

Some arrhythmias originate in the atria and others in the ventricles. The following conditions originate in the ventricles and can be life-threatening:

  • Ventricular tachycardia—the ventricles are beating too quickly to effectively pump blood
  • Ventricular fibrillation—in which the ventricles are fibrillating, quivering, or contracting in a rapid chaotic manner and are therefore unable to pump blood

Cadriovascular Disease

Any patient who has heart disease or has suffered from a previous heart attack has an increased risk of further heart complications that may require the use of defibrillators. Plaque or blockages in the arteries can restrict the amount of blood flow to the heart and impair its ability to function properly.


If your heart is enlarged, weak, or damaged from cardiac disease, it may have difficulty pumping blood effectively. Previous heart attacks can damage the muscle tissue (cardiomyopathy) causing it to become thickened or weak and affect the volume of blood the heart is able to eject with each contraction. Cardiomyopathy is often an underlying condition in seemingly healthy athletes who experience cardiac arrest.

Congenital Heart Defects

Some heart problems are present at birth and they may affect the heart’s rhythm. Some defects cause arrhythmic propensities and thus increase the risk of causing ventricular arrhythmias.

Recreational Drug Use

The American Heart Association reports that 15,000 people in the U.S. die each year from cocaine use and related incidents. Cocaine affects the central nervous system and causes damage to the heart, putting users at increased risk of SCA. Smoking crack cocaine increases the risk even more.

Recreational drug use can result in sudden cardiac death even in first-time users, and makes otherwise healthy young people vulnerable to life-threatening heart rhythms. When cardiac arrest occurs, a drug-use scenario is least likely to include access to defibrillators or sober bystanders who can provide cardiopulmonary resuscitation (CPR).