First degree heart block
Informed by recognized medical guidance
Overview
First degree heart block is a condition where the electrical signal that tells your heart to beat is slightly delayed as it moves from the upper chambers (atria) to the lower chambers (ventricles). This delay is mild and usually does not cause problems. Many people with first degree heart block have no symptoms and do not need treatment.
Key facts
- It is a type of heart block – a delay in the heart's electrical system.
- Most people with first degree heart block are healthy and have no symptoms.
- It is often found by chance during an electrocardiogram (ECG) test.
- Treatment is usually not needed unless there is an underlying heart condition.
Yes, first degree heart block is quite common. It can occur in people of all ages, including healthy young adults and athletes.
It can affect anyone, but it is more common in older adults, athletes, and people with certain heart conditions or taking certain medications.
Symptoms
- Fainting (passing out)
- Chest pain or pressure
- Severe shortness of breath
- Sudden, severe dizziness
- ⚠Ongoing dizziness that doesn't go away
- ⚠Palpitations that are new or getting worse
- ⚠Feeling like your heart is beating very slowly or irregularly
Common symptoms
- Most people have no symptoms at all.
- Some people may feel occasional mild dizziness or palpitations (a feeling of skipped or extra heartbeats).
Symptoms in children
- In children, first degree heart block is often harmless and causes no symptoms. It may be found during a routine check-up or sports physical.
Symptoms in older adults
- Older adults may have first degree heart block along with other heart conditions. Symptoms, if any, are usually mild, such as tiredness or light-headedness.
Causes
Main causes
- A naturally slower electrical system – some people are born with a slight delay.
- High vagal tone – common in athletes and young people.
- Certain medications (for example, some drugs for blood pressure or heart rhythm).
- Underlying heart conditions, such as coronary artery disease or inflammation of the heart muscle.
- Electrolyte imbalances (e.g., low potassium or magnesium).
Risk factors
- Being very physically fit (athletes often have slower heart rates and mild delays).
- Increasing age.
- Having a heart condition like coronary artery disease or cardiomyopathy.
- Taking medications that slow the heart's electrical conduction.
When to see a doctor
See a doctor urgently if:
- If you faint, have chest pain, or severe shortness of breath, call your local emergency number immediately.
Book a routine appointment if:
- If you notice new or worsening dizziness, palpitations, or feel your heart is beating unusually slowly, make an appointment with your doctor.
- If first degree heart block is found on an ECG and you have no symptoms, your doctor may still want to check your overall heart health.
Diagnosis
First degree heart block is usually diagnosed with a simple, painless test called an electrocardiogram (ECG or EKG). This records the electrical activity of your heart.
Tests that may be done
- Electrocardiogram (ECG) – the main test to see the delay.
- Holter monitor – a portable ECG worn for 24 to 48 hours if symptoms come and go.
- Echocardiogram – an ultrasound of the heart to check heart structure if needed.
- Blood tests – to check for electrolyte imbalances or thyroid problems.
What to expect at your appointment
Your doctor will perform an ECG, which takes about 10 minutes. You'll lie down while small stickers (electrodes) are placed on your chest, arms, and legs. It does not hurt. If your doctor suspects an underlying condition, they may order more tests.
Treatment
Most people with first degree heart block do not need any treatment. If there is an underlying cause, such as a medication or another health problem, that will be addressed. Treatment is only considered if the delay becomes more severe or causes symptoms.
Self-care at home
- Stay active and eat a heart-healthy diet – these are good for your overall heart health.
- If you are taking medications, do not stop or change them without talking to your doctor.
- Keep all follow-up appointments with your healthcare provider.
Medical treatments
If first degree heart block is caused by a medication, your doctor may adjust the dose or switch to a different medicine. If it is due to an electrolyte imbalance, correcting the imbalance can resolve the delay. Rarely, if the condition worsens and causes symptoms like fainting, a pacemaker (a small device placed under the skin to help regulate the heartbeat) may be considered.
When is surgery considered?
Surgery is not used for first degree heart block. In the rare case that a pacemaker is needed, it is a minor surgical procedure to implant the device.
Living with this condition
For most people, first degree heart block does not affect daily life. You can continue with your normal activities, including exercise, work, and travel.
Lifestyle tips
- Eat a balanced diet rich in fruits, vegetables, and whole grains.
- Get regular exercise, such as walking, swimming, or cycling.
- Avoid smoking and limit alcohol.
- Manage stress through relaxation techniques or hobbies you enjoy.
Diet and exercise
A heart-healthy diet and regular exercise are recommended for everyone, including those with first degree heart block. There are no specific restrictions. If you are an athlete, your doctor may give you individual advice.
Mental health and emotional wellbeing
Being told you have a 'heart block' can be worrying, but remember that first degree heart block is usually harmless. If you feel anxious, talk to your healthcare provider. They can reassure you and answer your questions.
Prevention
In most cases, first degree heart block cannot be prevented because it may be a normal variation or related to aging. However, maintaining a healthy heart can reduce the risk of heart conditions that might cause it.
Vaccines
No specific vaccines are recommended for preventing first degree heart block.
Screening programmes
Routine screening is not needed for the general population. An ECG may be done if you have symptoms or risk factors.
Complications
If left untreated
- First degree heart block typically does not cause complications. In rare cases, it may progress to a more severe heart block, especially if underlying heart disease is present.
- If progression occurs, symptoms like dizziness, fainting, or a very slow heart rate may develop.
Long-term outlook
The outlook is excellent. Most people with first degree heart block live normal, healthy lives without any issues. It is often a benign finding that requires no treatment. If an underlying cause is found, treating it usually resolves the delay.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 9, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.