Slow heart rate - what does a low heart rate below 60 (50) mean? Can it be dangerous?

Slow heart rate (bradycardia) occurs in two circumstances. The first is the physiological form, which has no disease cause. The second group consists of pathological (disease) bradycardia.

Normal pulse rate = 60-100 beats per minute.
Some authors give a value of 50 to 100 per minute.

The activity of the heart is provided by its own automated system. The generation of the impulse that determines the frequency comes from the sinoatrial node.

The sinoatrial node gives a rate of 60-100 impulses per minute.

The heart is also partly influenced by the nervous system, more precisely by the sympathetic and parasympathetic systems.

The sympathetic increases cardiac activity.
The parasympathetic slows the heart.

The heart rate itself is influenced by multiple factors such as age, how trained a person is, time of day, physical or mental activity, body temperature and other influences of the body (autonomic control by the sympathetic and parasympathetic).

Example...

During physical activity or when under stress and mental strain, the heart rate rises, even above 120 pulses per minute.

Conversely...

A drop in heart rate is normal (physiological) during sleep, at rest (for example, even after lunch).

A rapid pulse is referred to as tachycardia - tachyarrhythmia.
A slow heart rate as bradycardia - bradyarrhythmia.

It happens that at night during sleep the frequency drops below 40 pulses per minute.

Bradycardia in trained people and athletes?

Trained people, professional athletes, top athletes have a lower pulse rate, even below 50 pulses.

Bradycardia in this case is normal and common.
It is not a manifestation of disease or heart disease.
It is a variant of normal frequency.

FAQ:

My heart rate is below 50, is that okay?

The answer is in the form of another question:

If so, you have nothing to worry about. A low pulse in this case is not dangerous.

The next question is: Is a low pulse dangerous?

Yes, it can be. This is true in the case of a pathological cause.

Bradycardia as an arrhythmia

An arrhythmia is a technical term for a deviation of the heartbeat from normal. It may not only indicate a decrease or increase in frequency, but also a deviation from regularity.

Arrhythmia = dysrhythmia = heart rhythm disturbance.
Bradycardia - from the Greek brady (slow) and cardia (heart).

With dysrhythmia, as arrhythmia is otherwise known, an examination is needed to find the source of the problem. Treatment is then tailored to this.

The primary pacemaker, that is, the creator of the impulse for heart activity, is the sinoatrial node. The junctional rhythm is referred to as the secondary pacemaker.

If both pacemakers fail, a third (tertiary) pacemaker takes over. This is the ventricles. They produce a rhythm of 20-40 pulses per minute. This is also known as idioventricular rhythm.

This happens when there is no impulse from the atria to the ventricles.

Atrial rhythm occurs when there is a disturbance in the generation or conduction of the impulse for cardiac activity in the atrial and sinoatrial node. It forms in the atrioventricular junction (junction/division, at the site of the atrioventricular node and His bundle).

In this case, the heart rate is about 40-60 pulses per minute.

In bradycardia, terms such as sinus bradycardia, AV block (grade I, II or III) or Sick Sinus Syndrome (SSS), i.e. sinoatrial node disease, are also known.

Asystole = cardiac arrest.

The causes of cardiac rhythm disturbances are diverse. They may result from organic heart disease. In some cases, they arise without damage to the structure of the heart and the cardiac conduction system. Accordingly, they are divided into intrinsic and extrinsic.

The table shows the division into internal and external causes of bradycardia

The most common cause of heart rhythm disturbance is the underblooding of the heart muscle and the sinoatrial node (the site of the formation of regular heart rhythm). It is primarily coronary artery disease.

Ischaemic heart disease is a long-term form of ischaemia (reduced and insufficient blood supply to the heart muscle). It is chronic.

The acute form of ischaemia (bloodlessness) is a heart muscle infarction.

Other causes of dysrhythmias include:

• abnormalities in ion levels - calcium, magnesium, potassium
• disturbance of acid-base balance - in short, the article Claims of acidification are nonsense
• disease of the heart muscle (myocardium) - cardiomyopathy
• imbalance of the autonomic nervous system - anxiety, stress, shock
• arrhythmia-inducing substances - drugs, alcohol, caffeine, medications, adrenaline, digoxin, diuretics, antiarrhythmics
• diseases of other systems - endocrine disorders (thyroid)
• hypothermia
• and others

How is it manifested and what is its course?

Bradycardia may be asymptomatic. The person has no discomfort.

The second form is bradycardia with symptoms. Symptoms such as fatigue, malaise are present.

The person tends to get tired and is unable to perform physical activity. With reduced blood flow and insufficient blood supply to the brain, a feeling of fainting or fainting follows.

Symptoms of slowing of the pulse:

• Weakness
• Fatigue
• Inefficiency
• shortness of breath, shortness of breath
• feeling of palpitations, feeling of skipping heartbeat, irregular heartbeat
• feeling faint, fainting, syncope
• repeated collapse
• low blood pressure to shock state
• stenocardia (chest pain)
• sudden cardiac death

Diagnosis

First of all, a medical history is taken. The person describes his or her difficulties. Then a physical examination is needed, this includes taking blood pressure, pulse and others. For the pulse, its frequency, regularity, quality and whether it is the same in both limbs are assessed.

This is followed by special investigations, i.e. ECG and ECG Holter (24-hour recording). ECG is used to assess the functionality and electrical activity of the heart, i.e. the cardiac conduction system.

What is the treatment?

The treatment depends on the underlying cause. This may be reversible, such as an abnormality in the ion/minerals, hypothermia or an overdose of arrhythmia drugs (digoxin, beta-blockers).

The second group consists of irreversible causes such as organic damage or sinoatrial node disorder.

Treatment options are:

• lifestyle changes
• pharmacological treatment - drugs to modify cardiac activity
• temporary and permanent pacing - a device to replace the natural pacemaker
  • implantation of a pacemaker or cardioverter-defibrillator

Interesting information can also be found in the articles:

• Measuring blood pressure, pulse or breathing at home. How to know the values?
• What are the values of low, normal and high blood pressure?
• How to prevent cardiovascular disease?
• What are the most common causes of heart palpitations?
• First aid for myocardial infarction
• Thyroid gland and symptoms of problematic activity