Syncope is transient fainting due to decreased blood flow to the brain.


All the general information concerning the mechanisms causing unconsciousness, the symptoms and the different types of syncope are presented under the heading: The syncope, a dizzying subject.



Cardiac syncope

Cardiac syncope, as the name suggests, can be a consequence to a heart disease.

Normally, this type syncope is due to a heartbeat disorder. A natural pacemaker and the cell circuits act as electrical wires controlling the heart rate. When this pacemaker or these wires are affected, the heart beats too slowly. This is called bradycardia.

Also, abnormal circuits can form in the heart. These can take control of the heart and the rate can become too fast. This situation is known as tachycardia.


In many cases, bradycardia and tachycardia do not have any effect on blood pressure. However, in some cases, there can be a decrease in blood pressure when the heart rate is too slow or too fast.

More rarely, there is a structural problem. For example a heart valve disorder may be the cause.

Cardiac syncope may be preceded by palpitations (slow or fast) or pain in the chest. Elderly people and those with a known heart disease are more at risk.


Which tests can be requested?

The tests performed depend on the doctor evaluating the syncopal episode and his or her clinical suspicion.

The electrocardiogram (ECG) is the basic test for heart disease. The ECG is the exam where electrical sensors are placed on the patient's chest to record cardiac electricity.

In addition, during a medical examination in the emergency room or while being hospitalized, the patient can be evaluated using telemetry or a monitor. Telemetry is like a continuous ECG appearing on a screen. It can detect disorders of an intermittent heart rhythm or monitor heart rate in patients who have an already known cardiac rhythm disorder.

For people with frequent symptoms, a Holter monitor can be installed. This is a telemetry device that is worn at home or in the hospital for 24 to 48 hours.

If symptoms occur at a longer interval, a cardiomemo or a cardiac telemonitor may be installed for 2 weeks. Just as a Holter, it is a portable telemetry device.

Finally, if a high suspicion of cardiac rhythm disturbances persists, an implantable monitor may be proposed. It consists of a small device that is installed under the skin at the thorax level. It has the same role as telemetry, but can be worn for a longer period.


In addition, when a cardiac disease is suspected, the investigation is completed by a transthoracic echocardiogram, which assesses the heart’s effectiveness. This test uses ultrasound, just like a pregnancy ultrasound, in order to better see the heart muscle and its valves.

In some cases, nuclear medicine examinations can be done to detect the presence or absence of a problem in the coronary arteries. Coronary angiography may even be required.


What are the risks related to health?

Cardiogenic syncope has greater consequences because it does not respond to the maneuvers already described. It carries a greater risk of injury because of its more brutal nature, it does prevent falls and, more rarely, it can be responsible for sudden death.


What is the treatment?

As described above, cardiac syncope may result from several different causes and its treatment depends on the medical investigation and diagnosis. The treatment will then be decided upon depending on the cause of the cardiac syncope, whether it be an electrical, valvular or coronary heart problem.