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Sudden Cardiac Arrest


You can hear it every time you put your head to someone’s chest: the lub-dub, lub-dub, lub-dub of a heart pumping 60 to 80 beats per minute, delivering oxygenated blood to organs and tissues throughout the body. The pumping action of your heart is controlled by an electrical system, which sets and regulates the rhythm and keeps your heartbeat steady. 

Sometimes, however, that electrical system can go haywire, causing the heart to beat erratically, slower or more quickly, or in irregular patterns, and sometimes it even stops beating altogether. When the heart stops pumping blood, it’s called cardiac arrest. If immediate action isn’t taken to resuscitate the heart, the person will die.

Around 300,000 to 400,000 people experience cardiac arrest every year. It’s possible to survive cardiac arrest without lasting damage only if treatment is quickly delivered. A delay may lead to brain damage or even death. At present, cardiac arrest is one of the leading causes of death in the United States.  

Are there known risk factors that increase your risk for sudden cardiac arrest?

The most common conditions that increase your risk for sudden cardiac arrest are as follows:

  • Coronary artery diseaseA build-up of plaque in your arteries may cause them to narrow, obstructing blood flow to the heart. This can lead to a heart attack, which can lead to scar tissue that damages the heart’s electrical system, raising your risk of cardiac arrest.
  • Congenital heart disease: Each year, an estimated 1% of babies in the U.S. are born with heart conditions, some of which are identified early on while others remain undetected. Examples include long-QT syndrome, ARVC, and hypertrophic cardiomyopathy. These heart conditions can cause changes in the heart’s electrical system or changes in the heart musculature that can affect the heart’s electrical system. Detecting heart disease is a key reason why doctors listen to your heartbeat when conducting a physical exam.
  • Family history of cardiac arrest. If someone in your family has experienced cardiac arrest, your risk rises significantly.    

What causes cardiac arrest?

Most cardiac arrests are caused by irregularities in heart rhythm, called arrhythmia. There are a variety of types of arrhythmia, some more worrisome than others. For instance, some arrhythmias (which may require monitoring and treatment by your doctor) include atrial fibrillation, Wolff-Parkinson White syndrome and paroxysmal supraventricular tachycardia (PSVT). More severe arrhythmias, which also require treatment, include ventricular fibrillation, ventricular tachycardia or progressive bradycardia.

Less common causes of cardiac arrest include significant electrolyte abnormalities or other severe medical illnesses.   

What’s the difference between cardiac arrest and heart attack?

A heart attack (what doctors call a “myocardial infarction”) occurs when an artery is blocked (from a blood clot or constriction), preventing oxygen-rich blood from reaching the heart. If that blocked artery is not quickly unclogged, heart tissue begins to die. This damage can take anywhere from a few minutes to hours to set in, depending on how much blood is able to get to the heart. Heart attacks can be fatal, and sometimes can cause life-threatening arrhythmias leading to cardiac arrest. 

Cardiac arrest, or sudden cardiac death, is when the heart stops, due to a disruption in the electrical system. People who are having a heart attack, or who have had one in the past, are usually more likely to have cardiac arrest.   

How is cardiac arrest treated?

A cardiac arrest needs to be treated quickly, within minutes, or the patient is at risk for severe brain damage and death. The immediate goal is to get the heart to resume beating.

The best way to do this is with an automated external defibrillator (AED), which effectively jump-starts the heart by delivering electrical energy to it. This device that can be used by anyone to send an electric pulse or shock to the heart. AEDs can be found in many public spaces.

Cardiopulmonary resuscitation (CPR) can be used to pump blood to vital organs until the heartbeat is restored. People who are trained in CPR can greatly improve changes of surviving cardiac arrest with mouth-to-mouth breathing and chest compressions. Anyone who isn’t trained can perform hands-only CPR, which is a two-step process, according the American Heart Association:

  1. Call 9-1-1 or ask someone else to make the call
  2. Push hard and fast in the center of the chest

Cardiac arrest is a medical emergency. After initial resuscitation, patients need to be admitted to the hospital for monitoring by medical professionals. Diagnostic tests, including electrocardiography (ECG), blood pressure monitors and more, will be done to identify what caused the cardiac arrest. The patient will be closely monitored and cared for until the cause is known and a treatment plan is started and shown to be effective. 

How can you prevent a cardiac arrest?

Yale Medicine Electrophysiology & Cardiac ArrhythmiaYale Medicine Electrophysiology & Cardiac ArrhythmiaPatients at risk for cardiac arrest, especially those who have already experienced one, may need an implantable cardioverter defibrillator (ICD). Requiring a minor surgical procedure to put in place, this device detects the electrical activity in your heart and delivers electrical shocks or other therapies to bring the heart back to its normal rhythm when an irregularity occurs.

It’s also important for patients who have any of the heart diseases listed above to manage those diseases with medications and avoid overexerting their heart during physical exercise.  

What’s special about the way Yale Medicine treats cardiac arrest?

The Yale Medicine Electrophysiology & Cardiac Arrhythmia team uses a patient-centered approach to treat patients with cardiac arrest. “In addition to finding out why the patient had a cardiac arrest, we look for immediately reversible causes and first treat those conditions,” says Ralph DeBiasi, MD, a Yale Medicine electrophysiologist. The treatment may involve opening blocked arteries or other therapies to try to prevent another cardiac arrest, he says. “In most cases, we suggest an ICD be placed. We perform this procedure commonly and implant several hundred per year.” 

Yale Medicine specialists follow up with both patients and their cardiologists with the goal of preventing another cardiac arrest. They provide continuing routine office follow-up visits, and any indicated testing and treatments, as well as remote monitoring of the patients ICD, and work with the patient's regular cardiologist to prevent another cardiac arrest.