Syncope is a temporary loss of consciousness, commonly called fainting.
What causes syncope?
Syncope is caused by reduced blood flow to the brain, which results in loss of consciousness. When adequate blood flow resumes, you regain consciousness. Common causes of syncope are low blood pressure (hypotension) or slow heart rates. The brain simply does not receive adequate oxygen and glucose from the blood stream, causing you to pass out.
While syncope alone is generally not life threatening, it may be a symptom of a more serious condition, and you should receive a prompt evaluation. Learn more about our treatments for arrhythmias.
Symptoms of syncope
- Dizziness, sometimes after exercising
- Feeling lightheaded
- Irregular heartbeat (described as a fluttering in the chest)
Your doctor will want to investigate why you are experiencing syncope. Some diagnostic tests used to determine the cause include:
- Blood tests: Your doctor will examine your sugar levels and make sure you are not dehydrated.
- Electrocardiogram: An ECG or EKG records the electrical activity of the heart and shows abnormal rhythms (arrhythmias or dysrhythmias). Learn more about ECGs.
- Tilt table test: During this test, you lie on a table that moves from side to side. We record your blood pressure and pulse as the table is tilted. This test will sometimes show an arrhythmia that contributes to the syncope.
- Echocardiogram: This is an ultrasound of the heart as it beats. It may help to determine if there is an unusual cardiac rhythm. Learn more about echocardiograms.
- Electrophysiology study: This is a catheter-based test of the heart’s electrical system.
Syncope is usually treatable. The cause of the syncope will determine the treatment. If you have cardiac arrhythmias, your cardiologist may recommend:
- A pacemaker to treat slow heart beats
- An implantable cardioverter defibrillator (ICD) to monitor and correct life-threatening rapid rhythms. Learn more about our arrhythmia treatments, including ICDs.
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