Bradycardia

What is bradycardia? Bradycardia is a cardiac arrhythmia and describes a heartbeat that is too slow with less than 60 beats per minute . So those affected have a very slow pulse.

Is Low Heart Rate Dangerous?

Not necessarily. For example, it is not uncommon for bradycardia to occur at night. Our body lowers its heart rate when we sleep. Also, performance and endurance athletes often have a low heart rate. This is not a problem because your well-trained heart has a high stroke volume. It takes fewer blows to supply the organism with oxygen. So bradycardia is a rather good sign here.

It looks different with untrained people. If your heart rate is too low, it can be dangerous. If your heart is constantly beating too slowly, less blood will circulate through your body and your organs will lack oxygen and nutrients.

Possible symptoms of bradycardia:

• Affected people feel dizzy quickly
• are exhausted
• suffer from shortness of breath
• even pass out briefly

If left untreated, arrhythmias such as bradycardia can be life-threatening. In very rare cases, the slow heartbeat leads to cardiac arrest with sudden cardiac death .

The transition between normal and pathological is fluid. A doctor should always assess whether bradycardia is harmless, dangerous, or life-threatening after a thorough examination of the person concerned.

How does bradycardia occur?

The arrhythmia bradycardia occurs when the conduction system of the heart is disturbed. The cause can be, for example, a malfunction of the sinus node - the clock of the heart - in the right atrium (also called sick sinus syndrome). From here, the electrical signals usually spread evenly over the heart muscle via the atrioventricular node (AV node): it contracts. The heart then pumps the blood continuously through the entire vascular system.

• If too few electrical impulses are generated for the heartbeat or if their transmission is impaired, sinus bradycardia occurs . The heart rate of those affected does not increase adequately and their body is not adequately supplied with oxygen. This is why people with sinus bradycardia feel powerless and short of breath even with the slightest exertion.

• The tachycardia is the opposite of to slow heartbeat: an overly rapid heartbeat. Doctors speak of it at more than 100 beats per minute, although the person concerned is not exerting himself but is at rest. In bradycardia-tachycardia syndrome , the heart rate that is too slow and too fast alternate.

• A blockage between the atrium and the ventricle can also cause bradycardia. If the sinus node fails completely, other areas of the heart take over the function of the clock (e.g. the AV node). As a pacemaker, it sends out fewer impulses. The result is a slow heartbeat.

If one of the arrhythmias is suspected, a doctor should clarify what is behind it.

What is Relative Bradycardia?

If our core body temperature increases by one degree Celsius, metabolic activity normally increases and the pulse rate increases by around eight beats per minute. If the heart rate does not increase despite a fever and the heartbeat is too low in relation to the temperature, doctors refer to this as relative bradycardia. It occurs in infectious diseases such as typhoid , legionnaires' disease or dengue fever.

Bradycardia: causes

Cardiac arrhythmias are usually the result of heart disease or other factors that bring the heart out of step.

The following heart diseases can cause a slow heartbeat :

• coronary artery disease
• Heart failure ( heart failure )
• Heart muscle disorders ( cardiomyopathy )
• Inflammation of the heart muscle ( myocarditis )

Sometimes other causes also cause bradycardia:

• Metabolic disorders such as an underactive thyroid
• Electrolyte disorders (potassium deficiency, magnesium deficiency)
• Lack of sleep and hypothermia
• Medication: Bradycardia can be triggered by beta blockers, digitalis preparations or rhythm medication.
• High alcohol, drug or nicotine consumption also increases the problem.

Bradycardic atrial flutter or fibrillation can occur when the AV node is disturbed. The electrical signals normally spread evenly over the heart muscle via the atrioventricular node: it contracts and the heart continuously pumps the blood through the vascular system. It usually works like a filter so that the excitement does not pass too quickly from the atrium to the ventricle when we try very hard. If, due to the disease, the AV node only allows every third to fifth excitation from the atrium to the ventricle, bradycardiac flutter occurs. The ventricular rate drops, although the atrial excitation is very rapid (from 240 to 340 beats per minute).

In bradycardic atrial fibrillation (from an atrial frequency of 340 beats per minute in an irregular rhythm), the atria fibrillate, while the ventricles follow a slow cycle due to the lack of impulses. If the frequency falls below 40 beats per minute, the typical symptoms of an insufficient supply of oxygen to the body and brain occur.

Cardiologists sometimes use the image of the heart as a car engine when describing atrial fibrillation. It is like a lot of misfires here, only a few of which get the engine running - that is, the heart to contract.

Bradycardia: symptoms

Bradycardia often causes little or no symptoms . People with a slow heartbeat can remain completely symptom-free. Above all, (competitive) athletes are used to the low resting heart rate and feel good about it because their body is still optimally cared for.

If the heart works very slowly in untrained people (less than 40 beats per minute), those affected may feel noticeably less productive . The reason: If the heart rate drops so much that not enough blood is pumped through the body's circulation, the organism lacks oxygen and nutrients.

In summary, the following symptoms can be signs of bradycardia:

• You feel generally unwell, listless and feel sick more often .
• They are noticeably less resilient . Even with little exertion, you become out of breath and you may feel a little dizzy .
• You may have difficulty concentrating or you may have visual disturbances due to decreased blood flow to the eyes .
• Also nervousness and anxiety may be a low heart rate and lack of supply order.
• Suffers less than 30 to 40 beats per minute, the oxygen supply to the brain, sufferers may be unconscious or in fainting fall .

Bradycardia: diagnosis

You can check for yourself whether the heart is beating too slowly if you sit down and relax and count your pulse for a minute. Is it less than 50 to 60 beats , which may indicate a bradycardia.

Many arrhythmias are nothing to worry about. Even so, if bradycardia is suspected, you should see your doctor so that he can make a diagnosis and determine whether therapy is necessary. Especially as soon as symptoms appear. So if you often feel dizzy or short of breath during exercise.

The doctor will talk to you first to make a diagnosis. He asks about underlying diseases (especially those of the heart) and asks about medications and over-the-counter herbal remedies you are taking. Explain exactly what brings you to the practice - and why you think about the diagnosis of bradycardia.

Those who think about the following questions are well prepared:

• What ailments do you suffer from?
• How often, how long and in what situations do they occur?
• Has the frequency and / or duration of the complaints increased?

You will then be physically examined by your trusted doctor . He measures the pulse and listens to the heartbeat. If he draws blood , certain metabolic diseases can be ruled out (for example an underactive thyroid).

To diagnose bradycardia, the doctor or cardiologist can record the heart currents with a resting EKG (electrocardiogram). In this way, it recognizes a slow heart rate and can search for the causes of the bradycardia.

Because the disorder may only occur now and then or only during physical exertion, the doctor may take a long-term ECG that records the heart rhythm over a 24-hour period. It shows how the heart behaves during the day.

Exercise tests (spiroergometry) can also be used to check your heart rate and rhythm when you are exerting yourself.

In some cases, an electrophysiological examination (EPU) of the heart is also performed. With this special cardiac catheter examination, the doctor determines the type and cause of the arrhythmia.

If a heart disease is suspected, an ultrasound of the heart (echocardiography) or a cardio MRI or CT are also possible.

Bradycardia: Therapy

Whether and how the cardiologist treats bradycardia depends on its cause and severity. A slow heartbeat that does not cause any symptoms does not always have to be treated immediately. In mild cases, home remedies can be like

• coffee
• Move
• Alternating showers

stimulate the blood circulation and increase the pulse.

Before starting therapy, the doctor must identify the trigger . If drugs such as beta-blockers cause bradycardia, the prescribing doctor adjusts treatment or stops the drug. Metabolic diseases such as an underactive thyroid can also lead to a slower heartbeat. It is important to treat the underlying disease here .

If the heartbeat drops permanently to 40 beats per minute and bradycardia symptoms such as dizziness that restrict everyday life are added, treatment makes sense. The attending physician can prescribe frequency-increasing medication (for example atropine) or implant a pacemaker that sets the heart back into a regular rhythm. If symptomatic bradycardia is not treated, there is a risk of heart failure and organ damage.

Good to know: With bradycardia medication, it often takes patience to find the right remedy and the right dosage.