Why people pass out—and when to seek medical attention
Losing consciousness briefly can be scary, but it's not always cause for alarm. Learn when to get help.
Passing out and briefly losing consciousness—for a few seconds to a few minutes—can be scary, but it's not necessarily a cause for alarm.
Syncope, the medical term for passing out, is usually related to a drop in blood flow to the brain. Many conditions can cause this, and most aren't serious.
Vasovagal syncope is the most common type of syncope and is usually not life-threatening. It occurs when your body reacts to certain triggers such as emotional distress, the sight of blood, or standing for a long time.
Cardiac syncope is caused by serious heart conditions that affect blood flow to your brain. These include:
- Abnormal heart rhythms
- Aortic stenosis
- Heart artery blockage
- Blood clots
- Heart failure
Other conditions that can cause near-syncope include orthostatic hypotension, where your blood pressure drops from a quick change in position, and postural orthostatic tachycardia syndrome (POTS), a rare condition in which your heart rate increases by at least 30 beats per minute after standing up.
What should you do if you pass out?
Passing out briefly, especially with warning signs such as being on your feet for a long time or experiencing a stressful situation, isn't usually an emergency, but make sure to discuss it with your primary care provider.
If you passed out without any warning signs (or injured yourself when passing out), you should seek medical attention right away, especially if you are over age 60.
Cardiac syncope often occurs suddenly and without warning signs. If you think you may have cardiac syncope, talk to your doctor.
Improve your heart health
If a heart condition causes you to lose consciousness, talk to our experts about possible treatments.
How is syncope diagnosed and treated?
“The first thing we need to do is understand why a patient is passing out and rule out any serious conditions that can cause it,” says cardiac electrophysiologist Paari Dominic, MBBS, MPH.
Your doctor will take your medical history and do a physical exam to better understand what happened when you fainted. Was it sudden or gradual? Did you have a warm or flushing sensation before you passed out, or did you pass out without any warning at all? The answers to these types of questions will help determine next steps.
To diagnose cardiac syncope, tests may include an electrocardiogram (EKG) and the use of diagnostic heart monitors, which can be worn anywhere from 24 hours to a month to provide more information on the heart’s activity.
More complex tests, such as an echocardiogram, a heart CT scan, or an angiogram, might also be considered.
“Once we determine the cause of the syncope, we can treat it,” Dominic says. “For example, if a fast heart rhythm is the cause, we treat it either with medications or an ablation procedure. But if the heart rhythm is too slow, we can treat it with a pacemaker.”
Cardioneuroablation is a new treatment option for vasovagal syncope caused by slow heart rate or pauses in the heartbeat. This minimally invasive procedure is only available in Iowa at the University of Iowa Heart and Vascular Center.
"For highly selective patients who haven’t responded to other treatments, cardioneuroablation can offer a much-needed and long-term solution that improves a person’s quality of life," says Dominic. "It’s another example of the innovative and state-of-the-art cardiac treatment we offer."