What’s bradycardia?
Bradycardia refers to a heart rate that is below the expected normal range. In an adult, a frequency of 60 to 100 beats per minute is generally assumed. Bradycardia would therefore be present if the heart rate fell below this value.
The age and also the training condition of a person must be taken into account. For babies and children, higher basic heart frequencies are generally considered to be natural. The values of a bradycardia would therefore be correspondingly higher. Very low frequencies can occur in very athletic people without showing any disease value.
Cardiac arrhythmia – What is behind it?
Usually the heart beats at a rate of 60-100 beats/min. If there is a change in the sequence of the heartbeats, this is called cardiac arrhythmia. The disorder can be visualized with the help of an ECG ́s.
Normally, the heart beats at a certain frequency and at the rhythm set by the sinus node, the so-called sinus rhythm. This natural rhythm can be disturbed, for example by occurring irregularly or arrythmically, too fast or much too slow. A heart action that is too fast is called tachycardia and one that is too slow is called bradycardia.
Cardiac arrhythmias do not always require treatment. However, when symptoms occur, it is often the case that a therapy of the arrhythmia or its cause is necessary. It is important that you get an overview of cardiac dysrhythmia. The following article is recommended: What are cardiac dysrhythmia?
Causes of bradycardia
One of the possible causes of a too low heart rate is a disturbance in the sinus node. The sinus node is naturally the “clock” of the heart. This is where the electrical excitation in the heart, more precisely in the atrium, is generated and from there spreads throughout the entire heart.
If the sinus node is defective or disturbed, it cannot function as a clock generator, which then manifests itself in a low heartbeat. Furthermore, so-called excitation conduction disorders can lead to bradycardia. The electrical excitation, which originates in the sinus node, cannot be passed on properly.
There is a blockage, so to speak, and the electrical excitation is interrupted. One of the places where a blockage occurs more often is the AV node. This node is normally intended to transmit the electrical excitation from the sinus node.
A defect results in irregular transmission or even interruption of the transmission and the resulting bradycardia. Furthermore, bradycardia can also be seen in atrial fibrillation, i.e. bradycardic atrial fibrillation. This is characterized by rapid and irregular excitation of the atria, which is only partially passed on, resulting in a low heart rate.
Hypothyroidism can also lead to a slower heartbeat. In addition to bradycardia, other symptoms of hypothyroidism may also be present, such as weight gain, brittle hair and fingernails. Bradycardia can also occur if there is a disturbance in the electrolyte balance, especially potassium in the blood plays a role here.
In athletes, bradycardia can be present without any disease value. Here the heart muscle is able to transport the same amount of blood with fewer beats due to its strong development. The heart can therefore fulfil its function despite the reduced number of beats.
Drugs can also cause bradycardia. Among the most important agents are beta-blockers, the so-called calcium antagonists and cardiac glycosides. In cases of known and pronounced bradycardia, these preparations are generally not recommended.
Only in certain cases and under medical supervision should the above-mentioned drugs be administered if bradycardia exists. The following articles can also provide you with a clear overview of the causes mentioned:
- Atrial fibrillation – What are the causes? – Hypothyroidism – A summary of the most important facts
- Cardiac arrhythmia – This is the reason
The Sick Sinus Syndrome comprises a series of cardiac dysrhythmias that are caused by a defective or not properly functioning sinus node.
If, for example, the sinus node cannot produce an electrical excitation at the correct rate or the transmission of the electrical excitation is disturbed, this is referred to as sick sinus syndrome. The malfunction can have different causes. Would you like to know more about the Sick Sinus Syndrome?
The so-called beta-blockers are drugs that are preferably used in the treatment of high blood pressure. Among other things, they lower the heart rate and the transmission of excitation to the heart. In the case of high blood pressure, this reduces the undesirable “high pressure” in the blood vessels.
Beta-blockers are contraindicated for people suffering from significant bradycardia, i.e. a heart rate of less than 50 beats per minute. The already low heart rate would be further reduced by the administration of the drug. As a result, severe side effects such as fainting and dizziness could occur.
What are the exact effects and side effects to be expected from the administration of beta-blockers? You can find out more about this under: Effect of beta blockersThe thyroid gland and its hormones influence a number of organs and bodily functions, including the heart. If the thyroid gland is malfunctioning, this can have a decisive effect on the heart.
If the thyroid gland is hypothyroid, bradycardia can occur in addition to other symptoms. In the course of a diagnostic clarification, the thyroid gland value or the blood values of the thyroid hormones in the but are always determined. If hypothyroidism is the cause of bradycardia, certain thyroid medications usually help to restore normal function and thus also to correct the bradycardia. What exactly are the values that indicate an underactive thyroid? This and much more can be found under: Values of hypothyroidism
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