Bradycardia: causes, symptoms and treatment

If the heart beats slower than normal, we speak of bradycardia. Under normal conditions, the heart rate starts when an electrical impulse is generated which, then, is sent by the sinus node – also called "sinoatrial" -, located in the right atrium.

This node is in charge of establishing the heart rate and rhythm. Therefore, it is considered a kind of "pacemaker." Sometimes if the conduction pathways are damaged, or if there is an additional pathway, the heart changes rhythm; therefore, it can beat too fast (tachycardia), too slow (bradycardia), or irregularly.

These abnormal beats are known as "arrhythmias" and They can occur in both the upper chambers (atria) and the lower chambers of the heart (ventricles). In this case, we focus on the definition of bradycardia and the treatments available for it.

What is bradycardia?

The term bradycardia refers to a number of conditions in which the heart beats less often than usual. In particular, there are less than 60 beats or beats per minute.

According to an article by Trends in Cardiovascular Medicine, it is a normal phenomenon in young athletes or as part of the aging process or disease. In turn, it can be classified according to the level of alternation within the hierarchy of the cardiac conduction system.

If the heart beats at an abnormally low rate, it is called bradycardia.

Read this article: 10 curiosities about the functioning of the human heart

Causes of bradycardia

Bradycardia can occur in athletes or in people who enter a state of deep relaxation. It is also common in patients with heart disease or who are under certain drug treatments. Its possible causes, according to the Mayo Clinic, include the following:

  • Damage to heart tissue due to aging.
  • Alterations in heart tissue due to heart disease.
  • Congenital heart defects.
  • Infections in the heart tissue.
  • Complication of heart surgery.
  • Lack of control of potassium or calcium levels in the blood.
  • Obstructive sleep apnea.
  • Inflammatory diseases, such as lupus.
  • Medicines for heart rhythm disorders.

Main symptoms

The clinical presentation of arrhythmias ranges from asymptomatic electrocardiographic signs to a wide variety of symptoms. In the case of bradycardia, the most common are the following:

  • Dizziness or lightheadedness
  • Fainting.
  • Fatigue.
  • Chest pain.
  • Difficulty breathing.
  • Confusion.

It is important to note that if the symptoms are severe, pharmacological management and the placement of an emergency pacemaker should be indicated.

Complications of the disease

Without prompt treatment, bradycardia can lead to health complications. Next, we detail the most relevant ones.

  • Inability of the heart to pump enough blood (heart failure).
  • Sudden cardiac arrest or sudden death.
  • Repeated fainting.
  • Changes in blood pressure (hypotension and hypertension).


To establish the diagnosis of bradycardia, it is crucial to find a causal relationship between the symptoms and the various abnormalities that may show up on the electrocardiogram (ECG). Given the intermittent and unpredictable nature of this condition, the process can be difficult.

It is important to take into account the medical history, and to perform a 12-lead surface ECG. Too An electrocardiogram holter recording (long-term Holter ECG) and a stress test can be performed.

Bradycardia treatment

Treatment of bradycardia should be limited to patients in whom a clear correlation between symptoms and rhythm has been documented. Patients who are asymptomatic do not require specific treatment.

In general, the first measure for the treatment of symptomatic people is the discontinuation of any medication that slows the heart rate. Further, we proceed to the intervention of any related underlying condition.

Ultimately, when other treatments don't work, the doctor suggests implantation of a permanent pacemaker. If so, the professional will inform all the necessary details, such as risks, benefits and preparation for its placement.

If patients reject the first line of bradycardia treatment, the doctor may suggest the placement of a pacemaker.

Read this article: Transcutaneous cardiac pacemakers: in which patients are they indicated?


Progression and prognosis of bradycardia will depend on various factors, such as the following:

  • Age.
  • Smoking.
  • Alcohol consumption.
  • The use of recreational drugs.
  • Coexisting cardiovascular diseases.
  • Thromboembolic complications.

The natural history of this alteration is highly diverse and often unpredictable. Patients with a history of fainting due to bradycardia may continue to have it recurrently.

The incidence of sudden death is low, and pacemaker treatment does not appear to improve overall survival. However, it does reduce morbidity.

In any case, it is advisable to maintain regular medical control, since appropriate interventions avoid complications. The family doctor or professional in cardiology will require tests and treatments whenever the alteration requires it.