Medical Moment: What is cardiac arrest?

By Dr. Nene Linda Ugoeke, Houston Methodist Hospital

February is American Heart Month, a time when everyone can focus on their cardiovascular health. Your heart is one of the most important organs in your body. So, it is important to recognize when you may have a problem with your heart.

The heart pumps blood to every other organ, providing the constant supply of oxygen and nutrients these systems need to function. This process is also involved in removing harmful metabolic waste, like carbon dioxide.

If the heart stops working properly, as is the case with cardiac arrest, your entire body also shuts down.

“Cardiac arrest is when the heart suddenly stops functioning.  In most cases, this results from certain malignant abnormal heart rhythms or arrhythmias,” explains Dr. Nene Linda Ugoeke, a cardiologist at Houston Methodist.

Arrhythmias result from problems with the heart’s electrical system. Not all arrhythmias are immediately harmful. But some, including ventricular fibrillation (v-fib) and ventricular tachycardia, can develop suddenly and lead to cardiac arrest.

“These types of irregular rhythms disrupt the heart’s ability to pump blood effectively,” explains Dr. Ugoeke. “When the brain, lungs and other vital organs aren’t getting adequate blood flow, it leads to loss of consciousness and breathing, as well as organ damage and eventually death.”

Depending on the underlying arrhythmia, some cardiac arrests can be treated by shocking the heart back into a normal rhythm using a defibrillator device. Regardless of the underlying heart rhythm during cardiac arrest, immediate cardiopulmonary resuscitation (CPR) is of utmost importance in increasing the chances of surviving a cardiac arrest or at least having the best possible outcome.

What causes cardiac arrest?

“One of the most common causes of cardiac arrest is a heart attack,” explains Dr. Ugoeke. “As blood flow to the heart is reduced, the injury experienced can set off cardiac arrest by triggering one of the dangerous rhythms.”

But a person with no known heart issues can also experience sudden cardiac arrest.

“There are genetic disorders that can make a person more prone to arrhythmias and, therefore, cardiac arrest,” explains Dr. Ugoeke. “For instance, cardiac channelopathy disorders affect how electricity transverses through the heart, setting a person up for arrhythmias.”

Cardiac arrest vs. heart attack: What’s the difference?

The terms heart attack and cardiac arrest are frequently used as synonyms, but in fact, they are unique conditions that should be understood distinctly.

While “cardiac arrest” is a term that generally describes the abrupt cessation of heart function, “heart attack”, formally known as myocardial infarction, specifically results from compromised blood flow to portions of the heart muscle, which occurs when the arteries supplying blood to the heart muscles become blocked. Failure to deliver enough oxygenated and nutrient-rich blood to the heart leads to the damage of heart muscle. This, in turn, can affect the heart’s rhythm and cause cardiac arrest.

A common cause of heart attack is coronary artery disease, a heart condition in which the coronary arteries narrow over time because of plaque buildup, a process called atherosclerosis. Sudden rupture of these plaques can cause complete blockage of the affected artery, resulting in a heart attack.

How to prevent cardiac arrest

Various heart conditions and medical conditions, in general, can predispose to cardiac arrest. Heart attacks resulting from coronary artery disease are a common cause. Therefore, taking steps to reduce your risk of developing coronary artery disease, or working with your doctor to establish an effective plan for managing the condition if you already have it, will reduce your risk of having a cardiac arrest from coronary artery disease.

Living a healthy lifestyle — eating a well-balanced, heart-healthy diet, exercising regularly and maintaining a healthy weight — can help protect your heart and arteries.

These behaviors can also reduce your risk of developing health issues that can lead to coronary artery disease, including:

  • High cholesterol
  • High blood pressure
  • Obesity
  • Diabetes
  • Smoking

Since cardiac arrest can occur in people who don’t have coronary artery disease, you may be wondering whether there are ways to screen for people who might be at increased risk of having cardiac arrest due to other heart conditions.

“We have ways to screen for conditions that may increase the risk of cardiac arrest, but screening isn’t appropriate for everyone,” adds Dr. Ugoeke. “Since we know these conditions can run in families, there are questions we ask first to help determine a person’s risk.”

Having a family member who died suddenly at a young age usually prompts screening.  Further tests are then done based on the results of the initial screening. In most cases, an electrocardiogram (ECG or EKG), which is a test that records the electrical signals of the heart, is a good starting point. However, some other imaging tests and even genetic testing on occasion are done when indicated.

Despite what we know about preventing cardiac arrests, they can occur unexpectedly. Therefore, Dr. Ugoeke emphasizes the importance of learning how to perform CPR, to ensure readiness when help is needed.

To schedule an appointment with a cardiologist at the Houston Methodist DeBakey Heart & Vascular Center in Baytown visit or call 281.837.7587.

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