The nation and the world had the opportunity to witness Damar Hamlin in full cardiac arrest during the January 2 Bengals/Buffalo Bills game, and the expert team of health care professionals who started treatment for him within one minute after he collapsed.

Certainly this was shocking, because he is a young professional football player. It was the intensive treatment on the field (CPR, defibrillation and intubation) and his transfer to a top medical facility that will mean a favorable recovery for him. However, this positive outcome is very rare.

It is estimated that there are over 350,000-plus out-of-hospital cardiac arrests (OHCA) in our country annually; there is a very high fatality rate of 90 percent. Even if the person makes it to the hospital, having been treated by EMS, there is only a 10 percent chance of long-term survival. Out-of-hospital survival is slightly better for children (13.2 percent) and a 43 percent survival rate for competitive sports-related OHCA, possibly due to the fact that there are usually health care professionals present who can initiate CPR (cardiac-pulmonary resuscitation and defibrillation) until EMS is present.

This article will outline risk factors that can lead to cardiac arrest, and provide the reader with warning symptoms. Most important is to discuss what you can do in case you witness a person undergoing acute cardiac arrest, in order to improve the chances of survival for that individual.

Causes of cardiac arrest

The primary reason for a cardiac arrest is that the heart’s malfunction leads to the development of abnormal rhythms like ventricular tachycardia (high heart rate) or fibrillation (uncoordinated contractions of the heart muscle), or extreme slowing of the heart contraction. The end result is insufficient movement of blood to the head/brain and body, with the person suddenly losing consciousness, stopping breathing and being pulseless.

Warning signs can include chest discomfort, shortness of breath, weakness, and fast-beating, fluttering or pounding heart palpations—but, again, there might be no warning.

Other factors that increase the risk of a cardiac arrest are family history of coronary artery disease, congenital heart abnormalities, smoking, being a male, uncontrolled high blood pressure, high cholesterol, obesity, diabetes inactive lifestyle, obstructive sleep apnea, chronic kidney disease and use of street drugs.

There is speculation that Damar Hamlin sustained a blow to his anterior chest wall that bruised his heart muscle. This led to ventricular fibrillation, along with bleeding into the sac (pericardium) surrounding his heart and into his lung cavity. This is known as commotio cordis. His treating doctors were investigating this, but are also looking for other possible reasons for his cardiac arrest.

When someone loses consciousness

What can you do if you witness a person who suddenly loses consciousness?

Your chance of witnessing a cardiac arrest is fortunately rare, unless you are living with a friend or family member who is at high risk for this to occur.

The most common scenario is that a person has collapsed, with no witness to the event.

Because no treatment is immediately rendered, this often leads to death. Survival is possible with appropriate cardiopulmonary resuscitation (CPR) or by just giving chest compression until emergency personnel arrives. If the event occurs in a public space, there is usually a defibrillator present that can be used.

This equipment, when activated, gives verbal directions on the placement of the chest paddles and what buttons to press. People are now purchasing these units for the home if someone lives there who is at high risk.

The American Heart Association has produced a self-learning training kit for hands-only CPR. Visit cpr.heart.org/en/cpr-courses-and-kits; the site provides a video link along with easy-to-understand steps.

If you are living with someone who is at high risk for a sudden cardiac event, you might want to reach out to the American Heart Association for more complete—and local—training on CPR and the use of a defibrillator.