Bradycardia is a heart rate in adults less than 60 beats per minute. There are harmless and dangerous forms of bradycardia. While healthy competitive athletes may have a slow heart rate due to their training, sometimes dangerous illnesses are behind it. Read more about the symptoms, diagnosis and treatment of bradycardia.
Bradycardia: description
With bradycardia, the heart beats too slowly. The normal heart rate is 60 beats per minute. Sometimes, bradycardia manifests itself only when the heart rate does not increase enough during exercise. Dizziness and shortness of breath can occur.
The electrical impulses for a heartbeat are usually formed in the sinus node. From there they are directed via the so-called AV node into the heart chambers, where the heart muscle cells then contract. Bradycardia can occur if too little electrical impulses are generated in the sinus node (sinus bradycardia), its conduction is disturbed (for example in a so-called thigh block) or other cardiac arrhythmias prevent a faster heart rate.
The heart beats too slowly
The AV node can also generate 40 to 50 electrical impulses per minute. He intervenes when the sinus node has failed. Even though these electrical impulses from the AV node can no longer be transmitted, the cardiac muscle cells are still able to generate a few pulses. The heart rate is then extremely low. The systemic circulation, however, is not able to manage with frequencies of about 20 to 30 beats per minute.
In sinus bradycardia, too few electrical impulses are generated in the sinus node. The heartbeat is slow but regular. Sometimes bradycardia occurs even in unborn or newborns. During childbirth, the unborn baby’s heart rate may drop during a pains. In apnea bradycardia syndrome premature babies often suffer from shortness of breath and a slow heartbeat.
Bradycardia: symptoms
Bradycardia often causes no symptoms. Athletes, for example, do not feel that their heart beats slower during rest periods than in non-athletes. Sometimes the heart rate is so low that less blood is pumped into the systemic circulation. As a result, the oxygen demand, above all, of the brain can no longer be sufficiently covered. Headaches, dizziness, unconsciousness, nausea and vomiting can all be the result.
Bradycardia: causes and risk factors
Bradycardia can have many causes. Sinus bradycardia is dangerous in athletes. Sometimes, however, the heart rhythm also slows down when taking certain medications. Especially medications, which have to be taken because of other arrhythmias, show this side effect. Sometimes they have to be discontinued or reduced in their dose.
A variety of heart diseases (e.g., myocardial infarction, atrial fibrillation) can trigger bradycardia. Sometimes thyroid hypofunction or potassium deficiency is responsible.
Bradycardia: examinations and diagnosis
When you feel your own pulse, you can partially feel the reduced heart rate. Especially important for the diagnosis of bradycardia is an electrocardiogram (ECG). Here, the heart currents are recorded by a recorder. Not only a slow heart rate, but also the cause can sometimes be detected on the ECG. In part, the ECG must be recorded for 24 hours or longer to detect the arrhythmia.
Bradycardia: treatment
A slow heartbeat does not always have to be treated. When symptoms occur and the heartbeat becomes dangerously slow (less than 40 beats per minute), therapy is usually required. Especially the pacemaker implantation is in the bradycardia in the foreground.
Bradycardia: disease course and prognosis
Bradycardia caused by exercise has a good prognosis. It can not be considered a disease, but is a side effect of physical training. A slow heartbeat caused by other heart disease can be treated very well by a pacemaker. Most patients are free of symptoms after implantation. A bradycardia, which is not treated, often leads in the course of heart failure and other organ damage.