Bradycardia: Symptoms, Causes, Diagnosis and Treatment
What is bradycardia?
Bradycardia means a slower-than-usual heart rate. A resting rate below 60 beats per minute in an adult is commonly described as bradycardia. However, a low heart rate does not always indicate disease: it may be normal during sleep or in well-trained athletes.
Its significance depends on symptoms, the underlying rhythm, accompanying heart disease and whether the heart rate increases appropriately during activity.
What symptoms can it cause?
- Dizziness or light-headedness.
- Fatigue and reduced exercise capacity.
- Shortness of breath.
- A feeling of faintness, near-fainting or loss of consciousness.
- Chest discomfort or difficulty concentrating.
Some people have no symptoms. Symptoms alone cannot establish that a slow pulse is the cause; the symptoms should be compared with a recording of the heart rhythm.
What causes a slow heart rate?
Possible causes include dysfunction of the sinus node, the heart's natural pacemaker; atrioventricular conduction block; age-related changes in the electrical system; myocardial infarction; and certain inflammatory or structural heart conditions.
Beta blockers, some calcium channel blockers, digoxin and antiarrhythmic medicines may slow the heart. Hypothyroidism, electrolyte abnormalities, low body temperature and sleep apnoea may also contribute. Medication should not be stopped without medical advice.
How is bradycardia diagnosed?
Electrocardiography (ECG)
An ECG identifies the rhythm and helps distinguish sinus bradycardia from conduction block. A brief normal recording does not exclude an intermittent problem.
Holter and longer rhythm recordings
Ambulatory monitoring measures heart rate during daily life and sleep, identifies pauses and conduction abnormalities, and helps relate symptoms to the rhythm. Longer monitoring may be needed when symptoms are infrequent.
Exercise testing
In selected patients, exercise testing assesses whether heart rate rises adequately with exertion.
Echocardiography and blood tests
Echocardiography evaluates cardiac structure and function. Thyroid function, electrolytes and other tests may identify reversible causes. Sleep apnoea assessment may be appropriate when slow rhythms occur predominantly at night.
Is bradycardia dangerous?
Not every slow pulse is dangerous. Asymptomatic physiological bradycardia may need no treatment. However, a slow rhythm associated with fainting, reduced blood flow, significant pauses or advanced conduction block requires careful assessment.
How is it treated?
Treatment depends on the cause. It may involve observation, reviewing medication, treating thyroid disease, correcting electrolyte disturbances or managing sleep apnoea.
A permanent pacemaker may be needed for symptomatic sinus node dysfunction or certain significant atrioventricular blocks. Not everyone with a pulse below 60 needs a pacemaker. The decision depends on the type of abnormality, symptoms, reversible causes and clinical findings.
When should you seek medical help?
Consult a cardiologist for a persistently slow pulse accompanied by fatigue, dizziness, breathlessness or near-fainting. Fainting, severe chest pain, marked breathlessness, confusion or serious weakness requires urgent medical assessment. Call 112 in an emergency.
Assoc. Prof. Sezen Bağlan Uzunget, MD — Cardiologist
This information is educational. Diagnosis and treatment require individual clinical assessment.
Türkçe: Bradikardi