Syncope is a temporary loss of consciousness caused by a decrease in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood flow to the brain. It can have multiple causes, which vary depending on the individual and the circumstances.
Read more: Syncope or loss of consciousnes
Cardiac Syncope
As the name suggests, cardiac syncope is caused by a problem within the heart. This type of syncope requires special attention because it may indicate a more serious heart condition.
In the vast majority of cases, it is related to an abnormal heart rhythm.
Our heart has a small group of cells known as the heart’s “natural pacemaker,” which acts like a conductor to regulate the heartbeat. It sends electrical signals through a sophisticated electrical network that coordinates each beat.
Suggested reading: The electrical system
Sometimes, this system slows down abnormally and the heart beats too slowly — this is called bradycardia.
Conversely, abnormal electrical circuits can take over, causing the heart to beat too fast — a condition known as tachycardia.
These rhythm disturbances do not always cause a drop in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure, but they can sometimes trigger a sudden drop, leading to a brief loss of consciousness.
In rarer cases, syncope may be caused by a structural problem in the heart, such as a malfunctioning heart valve.
Looking for Symptoms Before Syncope
In some people, palpitations“Palpitation” is a symptom related to an abnormality in heartbeats. There are several types of arrhythmias. This term is like a surname that encompasses several first names. — whether fast, irregular, or sometimes very slow heartbeats — may occur just before losing consciousness. Others may feel chest pain right before fainting.
However, in most cases, these warning signs go unnoticed or are not remembered by the person, either because the episode is very brief or the loss of consciousness happens too quickly.
This is why having a witness is so valuable: they can describe what happened before, during, and after the syncope, providing key information to help reach an accurate diagnosis.
An Older Population or Those with Heart Disease
Cardiac syncope occurs more frequently in older adults and in people with known heart conditions, such as an arrhythmia, valve disease, or heart failure.
Medical Evaluation
To properly understand a syncope episode, the physician needs as detailed a description of the event as possible — much like reconstructing a scene with all its nuances.
Every detail matters: the time of day, hydration or food intake, what the person was doing just before the episode, any warning symptoms, whether a witness was present, any injuries sustained, property damage if any, how consciousness returned, whether there was any urinary incontinence, and the person’s overall condition upon waking.
All of this information, taken together, helps guide the diagnosis and determine which tests should be performed.
Physical Examination
During the clinical evaluation, the physician will pay close attention to several key elements.
- Measuring bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure while lying down and then standing is essential to detect any abnormal drop in pressure.
- Listening to the heart (auscultation) helps identify possible rhythm disorders (arrhythmias) or unusual sounds, whether coming from the neck vessels or heart valves.
A neurological exam is also performed to assess motor skills, sensation, balance, and any signs related to the nervous system, to ensure that non-cardiac causes are not overlooked.
What Tests May Be Ordered?
The tests chosen depend primarily on the physician’s clinical impression, based on the nature of the syncope and the patient’s medical history.
- Electrocardiogram (ECG)
Typically, an electrocardiogram (ECG) is the starting point of the evaluation. This test involves placing electrical sensors on the chest to record the heart’s electrical activity. It can quickly detect certain abnormalities, such as arrhythmias or signs of cardiac distress.
The clinical investigation of cardiac syncope can generally be divided into three categories:
- Looking for a heart rhythm disorder
- Assessing the heart’s structure
- Detecting possible coronary arteryThe two coronary arteries, the right and the left, form the blood network that supplies the heart with oxygen and nutrients. They are located directly on the surface of the heart and branch into smaller vessels that disease
Identifying a Heart Rhythm Disorder
Several tools are available to help detect a heart rhythm disorder that might be responsible for a fainting episode.
- Continuous Cardiac Monitoring
In emergency or hospital settings, cardiac telemetry may be used. This is a form of continuous heart rhythm monitoring displayed in real time on a screen. It is useful for detecting transient abnormalities or for observing patients who are already known to have a rhythm disorder.
- Holter Monitor
For people with frequent symptoms, a Holter monitor may be recommended. This small device is worn for 24 to 48 hours, either at home or in a hospital setting. It continuously records heart activity to capture any suspicious events.
- Extended External Monitoring
When fainting episodes are infrequent and occur far apart, a cardiac event recorder — also known as an external loop recorder or cardiac telemonitor — may be proposed. This device is worn over an extended period, often up to two weeks, and allows the heart’s activity to be recorded precisely at the moment symptoms occur.
In daily life, more accessible tools such as a smartwatch or a device like Kardia can also be very helpful. These technologies allow patients to record their own heart rhythm when they feel unwell, providing valuable information for the medical team.
- Temporary Subcutaneous Monitoring
If a heart rhythm disorder is still suspected despite normal initial tests, an implantable loop recorder may be recommended. This small device is inserted under the skin of the chest during a minor procedure.
Its main advantage is that it offers continuous, long-term monitoring of the heart’s electrical activity — sometimes for several months — which increases the chances of detecting a rare or brief event, especially when fainting is infrequent but concerning.
For Patients with a Permanent Pacemaker
In people with a permanent pacemaker, identifying a possible arrhythmia is much easier. In addition to stimulating the heart when needed, a pacemaker continuously records electrical activity.
If a syncope episode occurs, the doctor can interrogate the pacemaker to retrieve the data recorded around the time of the event. This targeted analysis often helps identify the cause, whether it’s a rhythm disorder or another anomaly. It is a valuable, reliable, and readily accessible diagnostic tool in clinical settings.
Assessing Heart Structure
If structural heart disease is suspected, a transthoracic echocardiogram is usually prescribed. This imaging test, similar to a pregnancy ultrasound, allows doctors to assess how well the heart muscle is functioning and to examine the condition of the heart valves.
Looking for Coronary Artery Disease
Finally, when a problem affecting the coronary arteriesThe two coronary arteries, the right and the left, form the blood network that supplies the heart with oxygen and nutrients. They are located directly on the surface of the heart and branch into smaller vessels that is suspected, additional tests may be prescribed to complete the evaluation. One example is a treadmill stress test.
Other methods are also possible, including nuclear medicine tests that allow doctors to observe bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood flow in the heart.
In some cases, a coronary angiography may be recommended to directly visualize the coronary arteriesThe two coronary arteries, the right and the left, form the blood network that supplies the heart with oxygen and nutrients. They are located directly on the surface of the heart and branch into smaller vessels that using a contrast dye.
What Are the Health Risks?
Among the different types of syncope, cardiogenic syncope carries the highest risk. Unlike reflex syncope, it does not respond to usual preventive measures and often occurs suddenly, without warning signs.
This unpredictability significantly increases the risk of injury, especially if the person falls on a hard surface or in a hazardous environment.
In rare cases, this form of syncope may signal a serious heart condition and can even lead to sudden death — particularly if it is caused by a malignant arrhythmia or an untreated underlying heart disease.
That’s why a prompt and thorough medical evaluation is essential.
What Is the Treatment?
As mentioned earlier, cardiac syncope can have various causes, and its treatment depends directly on the results of the medical evaluation.
The goal is to treat the underlying cause — whether it’s a heart rhythm disorder (an electrical problem), valve disease (a defect in the heart valves), or a dysfunction of the coronary arteriesThe two coronary arteries, the right and the left, form the blood network that supplies the heart with oxygen and nutrients. They are located directly on the surface of the heart and branch into smaller vessels that.
Key Message
Cardiac syncope is a sudden loss of consciousness caused by a problem in the heart.
Unlike other types of fainting spells that develop gradually or come with warning signs, this one strikes without warning — which makes it particularly dangerous.
The greatest danger of cardiac syncope is the abrupt fall that accompanies it. Since the person has no time to sit down or brace themselves, they may fall with their full weight — sometimes onto hard surfaces or against objects.
This is why it is crucial to consult a doctor immediately if there is any head injury, no matter how minor, or if a bone fracture is suspected.
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