Cardiac Syncope (fainting)
Health and lifestyle FAQs
View our short videos specifically designed to answer all your questions about how your health and lifestyle affect your heart health.
What is cardiac syncope?
Syncope is when you lose consciousness temporarily, also known as fainting, passing out, or blacking out. It may last a few seconds or minutes. You should recover quickly and fully unless you injure yourself during your fainting episode.
You may require emergency care if you lose consciousness after a head injury, seizure, heart attack, or stroke. We do not consider this syncope.
Cardiac syncope vs vasovagal syncope
Cardiac syncope can be confused with vasovagal syncope, known as the common faint or neurocardiogenic syncope. Vasovagal syncope occurs as a response to a trigger that causes a sudden drop in blood pressure. These can include dehydration, seeing blood, having your blood taken, standing up too long or too fast, and experiencing a sudden and unexpected trauma. Some people with postural orthostatic tachycardia syndrome (POTS) experience this type of syncope.
Symptoms
The most common sign of syncope is fainting or passing out. However, some people experience pre-syncope or feel like they might faint without fainting.
Some people have warning signs before they are going to faint. You may feel lightheaded, dizzy, or sick. You might also have heart palpitations, sweaty palms, blurry vision, or tunnel vision. If you experience these warning signs, you should sit or lie down.
Lying down may help you avoid fainting, especially if you can raise your legs on something, as it allows blood to travel to the brain. If it doesn’t prevent it, you will still be safer as you are less likely to hurt yourself falling.
Cardiac causes of syncope
Syncope can have many causes, but we’ll discuss those related to cardiac causes here. Cardiac syncope refers to syncope caused by a heart problem, such as a rhythm disturbance or a structural problem, that prevents the brain from receiving enough oxygen and nutrients.
Heart conditions that can cause syncope include:
- An arrhythmia, such as ventricular tachycardia or a bradycardia
- Brugada syndrome, a genetic disorder that causes arrhythmias
- Aortic valve stenosis (narrowing of the aortic valve opening)
- Cardiovascular disease, such as heart disease
- QT interval disorders (Long or short QT)
- Aortic dissection (a tear in your aorta)
However, you can also faint due to dehydration, overheating, a sudden drop in blood sugar, exhaustion and stress. We recommend speaking to a doctor about your symptoms, including when you experience them. They may refer you to a cardiologist (heart specialist) if they suspect a heart condition is responsible for your fainting episodes.
Diagnosis
Our specialist will perform a physical exam and discuss your medical and family history to determine possible causes of syncope. To identify an underlying heart condition, we may recommend an electrocardiogram (ECG) to record your heart’s electrical activity.
Additional tests include an exercise stress test, echocardiogram, Holter monitor, implantable cardiac monitor, and a tilt table test. We may also perform blood tests, a CT, a cardiac MRI, and an electrophysiology (EP) study. These tests allow us to assess the severity of your condition and determine the most suitable treatments. If you need further tests, our specialist will explain which ones and why, for example, to rule out other underlying conditions.
Autonomic reflex testing can help diagnose autonomic neuropathy (damage to the autonomic nervous system), which can cause fainting. These tests monitor your blood pressure, skin temperature, blood flow, and heart rate.
Treatment
Once we have determined the cause, we will form a tailored treatment plan with you. You may require new medications or to change any you are taking, such as beta-blockers, calcium channel blockers, and other anti-arrhythmic agents.
If an arrhythmia causes syncope, we may recommend catheter ablation for a fast, irregular heartbeat or a pacemaker for a slow heartbeat. We may suggest an implantable cardioverter defibrillator (ICD) for people with ventricular tachycardia or heart failure. An ICD can also help prevent sudden cardiac death in those at risk.
A surgical procedure can treat a structural problem, such as an issue with your aortic valve or a narrowed or blocked artery. These procedures include aortic valve replacement or revascularisation techniques, such as angioplasty or coronary artery bypass graft (CABG).
Our specialist will discuss your treatment in depth so you understand its purpose and how it will work. We are happy to answer any questions to ensure you feel comfortable with our treatment plan.
Prevention
Treating the underlying cause of your episodes can prevent future ones. To prevent fainting, try clenching your fist when you start feeling lightheaded. You could also try sitting or lying down, tensing your arms, crossing your legs, or squeezing your thighs together. When sitting, it may help if you lean forward, placing your head between your knees.
Some people benefit from increasing their salt intake and drinking more water to avoid dehydration, though this typically prevents vasovagal syncope.
Book an appointment
At our world-class cardiology centre, we take the time to listen to your concerns, thoroughly assess your medical history, and tailor a personalised treatment plan that suits your needs.
We know that dealing with heart-related issues can be worrisome, and we provide the reassurance and support you need to make informed decisions about your heart health.
If you experience episodes of cardiac syncope, book an appointment with our specialist to determine the cause and seek private treatment.
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