Cardiac fainting and near-fainting symptoms, causes and treatment guidance.
Overview
What is cardiac syncope and presyncope?
- Cardiac syncope is a temporary loss of consciousness (fainting) caused by a heart condition that reduces blood flow to the brain
- Cardiac presyncope is the feeling that you may faint due to a heart-related problem, without actually losing consciousness
- These episodes may happen suddenly and can sometimes be a warning sign of a serious heart condition
What causes cardiac syncope and presyncope?
Cardiac syncope and presyncope happen when the heart cannot pump enough blood to the brain for a short time. This may happen suddenly and can sometimes be a sign of a serious heart condition.
Common heart-related causes include:
- Irregular heartbeats (arrhythmias), where the heart beats too fast, too slowly or unevenly
- Problems with the heart valves, such as a narrowed valve (aortic stenosis)
- Heart attack or reduced blood flow to the heart
- Heart muscle conditions that affect how well the heart pumps blood
- Inherited heart conditions that affect the heart's rhythm or structure
- Heart failure or other structural heart problems
Some medicines used for blood pressure or heart conditions may also increase the risk of fainting in certain people.
What are the greatest risks of having a syncope or presyncope?
Cardiac syncope and presyncope may lead to:
- Injuries such as falls or head injuries during a fainting episode
- Fainting while driving, exercising or operating machinery
- Reduced confidence and difficulty with daily activities due to repeated episodes
- Serious heart-related complications if the cause is linked to an abnormal heart rhythm or structural heart disease
- An increased risk of sudden cardiac arrest or sudden cardiac death in some cases
Signs and symptoms
Symptoms of cardiac syncope and presyncope may happen suddenly and can include:
Feeling faint, dizzy or light-headed
- Blacking out or briefly losing consciousness
- Palpitations (fluttering, pounding or racing heartbeat)
- Chest discomfort or chest pain
- Breathlessness
- Blurred vision
- Weakness or unusual tiredness
- Nausea or sweating before fainting
Warning signs
Seek urgent medical attention if fainting or near-fainting happens:
- During exercise
- With chest pain, breathlessness or palpitations
- Suddenly without warning signs
- After a head injury
- Repeatedly within a short time
- Along with confusion, difficulty speaking or weakness in an arm or leg
- In someone with known heart disease
Not all fainting episodes are caused by a serious heart condition. However, because cardiac syncope can sometimes be linked to heart rhythm problems or structural heart disease, medical assessment is important.
Tests to diagnose syncope and presyncope
Your doctor may recommend tests to check the heart and look for the cause of fainting.
Common tests include:
- Electrocardiogram (ECG/EKG): Records the heart's electrical activity and checks for abnormal heart rhythms
- Blood pressure and pulse checks: Helps identify changes in blood pressure and pulse rate linked to fainting episodes
- Blood tests: Checks for anaemia, infection or other medical conditions
- Echocardiogram (heart ultrasound scan): Looks at the heart's structure, valves and pumping function
- Holter monitor: A portable ECG worn for 24 hours or longer to detect irregular heartbeats
- Event monitor or implantable loop recorder: Records heart rhythm during symptoms that happen occasionally
- Computed tomography (CT) scan: May be used to obtain images of the heart or brain
- Exercise stress test: Checks how the heart works during physical activity
- Tilt table test: Assesses how blood pressure and heart rate respond to changes in position
- Electrophysiology study: A specialised test to assess the heart's electrical system in selected patients
Treatment
Treatment will depend on the cause of your fainting episodes and the results of your medical tests. The main aim of treatment is to prevent future fainting episodes and reduce the risk of complications. Some people may need lifestyle changes, medicines, procedures or heart devices.
Lifestyle and safety measures
- Drinking enough fluids if advised by the doctor
- Avoiding sudden standing
- Limiting alcohol
- Avoid driving or operating heavy machinery until you have been medically assessed and advised by your doctor
- Monitoring symptoms
Medicines
Doctors may prescribe medicines to:
- Control abnormal heart rhythms
- Treat heart failure or blood pressure problems
Certain medicines that trigger fainting episodes may be stopped or their dosage may be adjusted
Procedures and surgery
- Pacemaker: A small device placed under the skin to help the heart beat regularly if the heartbeat is too slow
- Implantable cardioverter defibrillator (ICD): A device that helps correct dangerously abnormal heart rhythms by delivering an electrical shock to the heart when needed
- Catheter ablation: A procedure used to treat abnormal heart rhythms by targeting small areas of heart tissue causing the problem
- Valve repair or replacement: Procedures used to treat damaged or narrowed heart valves that affect blood flow through the heart
Myths and facts
Fainting is always harmless.
Some fainting episodes may be linked to serious heart rhythm problems or structural heart disease and should be medically evaluated.
If you do not completely lose consciousness, it is not serious.
Presyncope (feeling like you may faint) can also be a warning sign of an underlying heart condition.
Only older adults experience cardiac syncope.
Cardiac syncope can occur at any age, especially in people with inherited heart rhythm conditions or structural heart disease.
A normal ECG always rules out heart-related fainting.
Some abnormal heart rhythms happen intermittently and may require longer monitoring such as a Holter monitor or implantable loop recorder.
You should immediately return to driving after a fainting episode if you feel better.
Driving should be avoided until the cause of fainting has been assessed and your doctor advises it is safe.
FAQs
What is the difference between syncope and presyncope?
Syncope means completely fainting or losing consciousness briefly, while presyncope refers to feeling as though you may faint without fully losing consciousness.
Can stress or anxiety cause fainting?
Stress and anxiety can sometimes trigger fainting in some people, but heart-related causes should be ruled out, especially if symptoms occur suddenly or during exercise.
When should I seek urgent medical attention?
Seek urgent medical care if fainting occurs during exercise, with chest pain, breathlessness, palpitations, after a head injury or repeatedly within a short period.
Will I need lifelong treatment?
Not always. Treatment depends on the underlying cause. Some people only need lifestyle changes, while others may require medicines or heart procedures.
Can cardiac syncope and presyncope be prevented?
In many cases, treatment of the underlying heart condition, avoiding triggers, staying hydrated (if advised), and following medical advice can help reduce future episodes.
