Causes, Symptoms and Treatment of Bradycardia

15 March, 2021
Bradycardia happens when the heart isn't beating as it should. Continue reading to find out more about its causes it and treatments in order to be able to address it if it happens to you.

The condition known as bradycardia happens when the heart beats at a slower rate than it should. Under normal conditions, the heart rhythm begins with an electrical impulse that then continues through the sinus node – also called “sinoatrial” – positioned in the right atrium.

This node is responsible for setting the heart rate and rhythm. It’s for this reason that we think of it as a kind of “pacemaker.” Sometimes, the heart rhythm changes if the conduction pathways are damaged, or if there’s an additional pathway. Therefore, it may beat too fast (tachycardia) or too slow (bradycardia), or just irregularly.

These abnormal beats are known as “arrhythmias” and can occur in both the upper chambers (atria) and the lower chambers of the heart (ventricles). This article will focus on the definition of bradycardia and the treatments available for it.

What’s bradycardia?

The term bradycardia refers to a number of conditions in which the heart beats at a slower rate than usual. In particular, there are fewer than 60 beats per minute.

According to an article in Trends in Cardiovascular Medicine, it’s either a normal phenomenon in young athletes or part of the aging process or disease. In turn, one can classify them according to the level of the alternation within the hierarchy of the cardiac conduction system.

A person reading an electrocardiogram.
A person whose heart beats with an abnormally low frequency has bradycardia.

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Causes of bradycardia

This condition often occurs in athletes or in people who are extremely relaxed. It’s also common in people with heart disease or those under certain drug treatments. Possible causes, according to the Mayo Clinic, include:

  • Damage to heart tissue due to aging
  • Alterations in heart tissue due to heart disease
  • Congenital heart defects
  • Infections in the heart tissue
  • A complication of heart surgery
  • Uncontrolled levels of potassium or calcium in the blood
  • Obstructive sleep apnea
  • Inflammatory diseases, such as lupus
  • Medications for heart rhythm disorders

Main symptoms

The clinical presentation of arrhythmias ranges from asymptomatic electrocardiographic signs to a wide variety of symptoms. The most common in bradycardia are:

  • Dizziness or lightheadedness
  • Fainting
  • Fatigue
  • Chest pain
  • Shortness of breath
  • Confusion

It’s important to note that a person with this condition requires pharmacological management and emergency pacemaker placement if their symptoms are severe.

Complications of the disease

Also, bradycardia can lead to health complications without timely treatment. The following are the most relevant.

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

Diagnosis

It’s crucial to find a causal relationship between the symptoms and the various abnormalities that may be present on a given electrocardiogram (ECG) in order to establish the diagnosis of bradycardia. The process can be difficult given the intermittent and unpredictable nature of this condition though.

It’s important to take into account the medical history and also to conduct a 12-lead surface ECG. In addition, there may be a need for an electrocardiogram (long-duration Holter ECG) and a stress test.

Treatment of bradycardia

This should be limited to patients with a properly documented clear correlation between symptoms and rhythm. Those who are asymptomatic don’t require specific treatment.

In general, the first step in the treatment of symptomatic individuals is the discontinuation of any medication that slows the heart rate. In addition, intervention for any related underlying conditions is undertaken.

Ultimately, the physician suggests the implantation of a permanent pacemaker when other treatments don’t work. The professional will provide all the necessary details, such as risks, benefits, and preparation for pacemaker placement if so.

A doctor holding a pacemaker.
The physician may suggest the placement of a pacemaker if patients refuse the first line of treatment for bradycardia.

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Prognosis

The progression and prognosis of bradycardia will depend on several factors, including:

  • Age
  • Smoking
  • Alcohol consumption
  • Recreational drug use
  • Coexisting cardiovascular disease
  • Thromboembolic complications

The natural evolution of this disorder is diverse and often unpredictable. Thus, people with a history of fainting due to bradycardia may continue to experience recurrent fainting.

The incidence of sudden death is low, and pacemaker therapy doesn’t appear to improve overall survival. However, it does reduce morbidity.

In any case, it’s advisable to maintain regular medical control, since appropriate interventions prevent complications. The family physician or cardiology professional will require tests and treatment whenever an irregular heartbeat requires it.

  • Vogler, J., Breithardt, G., & Eckardt, L. (2012). Bradiarritmias y bloqueos de la conducción. Revista Española de Cardiología, 65(7), 656–667. https://doi.org/10.1016/j.recesp.2012.01.025
  • Sidhu S, Marine JE. Evaluating and managing bradycardia. Trends Cardiovasc Med. 2020 Jul;30(5):265-272. doi: 10.1016/j.tcm.2019.07.001. Epub 2019 Jul 9. PMID: 31311698.
  • Alliance, A. (2018). Programa de Estudio y Tratamiento de las Arritmias Cardiacas. https://www.heartrhythmalliance.org/files/files/A-A Uraguay/100915-FINAL-AA-Uruguay-Bradicardia (ritmo cardíaco lento).pdf
  • Hernández, G. A. (2007). Symptomatic bradicardia and pacemaker use in the emergency room. Revista Facultad de Medicina (Colombia), 55(3), 191–209.
  • Vogler, J. (2015). ´ n Bradiarritmias y bloqueos de la conduccio. 65(7), 656–667.