What is it about ?
The heart is made up of two upper chambers (the atria) and two lower chambers (the ventricles). The heart muscle (myocardium) contracts under the influence of a small electric current. This electric current originates in the sinus node, a node of nerves that is in the right atrium. The current is transmitted from the sinus node to the muscle of the heart by a specific system of nerves. A second node (atrioventricular node), located between the atrium and the ventricle, connects the nerves in the atrium with those in the ventricles.
The muscle of the ventricles contracts when current reaches it. Normally, the heart beats between 60 and 100 times per minute. When the heart rate is less than 60 beats per minute, it is called bradycardia.
If the cause lies in the sinus node, which activates too slowly, it is called sinus bradycardia. This situation can result from chronic cardiovascular diseases, but it can also be a normal adaptation of the organism, in endurance athletes for example.
Bradycardia can also be due to wear and tear on the heart’s electrical conduction system, e.g. blockage of the second node (atrioventricular block). As a result, the conduction of current between the atria and the ventricles no longer works properly.
Sometimes sinus bradycardia is due to a cause other than the heart, such as vomiting, coughing, pressure in the brain, hypothermia, certain medications (eg for high blood pressure), or an underactive thyroid.
When the heart is healthy, this sinus bradycardia is usually not serious. It becomes problematic when it causes disturbances in consciousness or signs of heart failure.
How to recognize it?
A slow heart rate does not always cause symptoms. If your heart rate is very slow, you may experience dizziness, fatigue, shortness of breath, or even a fainting (syncope).
How is the diagnosis made?
The doctor will ask you about your symptoms. It will take your pulse and count the number of heartbeats per minute. If your heartbeat is too slow and / or irregular, your doctor may order an electrocardiogram (ECG).
The cardiologist can then perform other more specialized examinations, such as a echocardiography. This test allows you to visualize the heart by means of sound waves.
What can you do ?
If you experience dizziness, feel faint, or have a tendency to pass out easily, see your doctor.
What can your doctor do?
It is not necessary to start treatment if the situation does not bother you (a lot). If your symptoms are more pronounced, you will be referred to a cardiologist. If your pulse is very slow, you will be given atropine. Medicines that slow the heart rate will be stopped. Sometimes this alone is enough to make the symptoms disappear.
The choice between regular monitoring and implantation of a pacemaker depends on the cause and the severity of the symptoms.
a pacemaker is a small device with a battery, which the heart surgeon places under the skin, usually under the right or left collarbone, after lulling the area with local anesthesia. The pacemaker is connected to the heart by two wires and constantly monitors the heart rate. If the rhythm slows down too much, the device sends out a stimulus that contracts the heart. If you wear a pacemaker, you will need to visit the cardiologist regularly to check that it is working properly.
Want to know more?
www.mongeneraliste.be/maladies/arythmie-quand-le-coeur-a-des-rates
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