First Degree Heart Block: Causes, Symptoms, Treatment, Image

Medically Reviewed by
Dr. Aman Priya Khanna
First Degree Heart Block

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First Degree Heart Block
Medically Reviewed by Dr. Aman Priya Khanna Written by Sparshi Srivastava

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According to a study by Dorairaj Prabhakaran et al. in 2016, cardiovascular diseases (CVD) are the leading cause of mortality in India. Among these, first-degree heart block has a prevalence of 1-1.5% until the age of 60. After 60, the prevalence rises to about 6%.

Imagine your heart as a well-coordinated orchestra where each beat is perfectly timed. In first-degree AV block or heart block, there’s a slight delay in transmitting electrical signals between cardiac chambers. But is it serious, and what problems does it cause? The following blog discusses its causes, symptoms, and treatment. Read on to find out. 

What is a First-Degree Heart Block?

In a healthy heart, the electrical signals from the atria (the upper chamber of the heart) to the ventricles (the lower cardiac chamber) move efficiently. These impulses move through the AV node (a group of cardiac muscle cells between the chambers). 

In first-degree heart block, also called first-degree atrioventricular (AV) block, the electrical activity is slower than average. However, all signals still reach the ventricles. 

Is First-Degree Heart Block Serious?

There are three types of heart blocks - first, second, and third-degree. 1st degree heart block is generally considered the mildest form of the issue. In many cases, it is not considered a severe condition. The delay in the conduction of electrical impulses is minimal, and individuals often do not experience evident symptoms. However, sometimes, it can progress to second or third-degree AV blocks.

Signs and Symptoms of First-Degree Heart Block

Many individuals with 1st degree AV block may not experience any related health issues. It is commonly discovered incidentally during routine electrocardiograms (ECG) performed for other reasons.

In some cases, individuals may experience first-degree heart block symptoms like the following: 

  1. Lightheadedness

  2. Dizziness

  3. Palpitations or skipped heartbeat

  4. Fatigue 

However, these symptoms are nonspecific. They can also be caused by factors unrelated to heart block.

Causes of First-Degree Heart Block

First-degree heart block is typically caused by abnormalities in the cardiovascular electrical conduction system. The most common causes include:

  1. Genetic Factors: Sometimes, people are born with cardiac issues due to genetic mutations or inheritance. This is known as a congenital heart block. 

  2. Cardiovascular Diseases: A heart attack is the most common cause of AV block. Other issues like cardiomyopathy (cardiac muscle disease) and heart valve disorders can disrupt the normal conduction of electrical signals. 

  3. Open Heart Surgery: During the operation, manipulating the cardiac tissues and conduction pathways can disrupt the standard electrical signals, leading to first-degree heart block. 

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Risk Factors of First-Degree Heart Block

Several factors can increase the risk of first-degree heart block. However, having multiple aspects does not necessarily indicate that individuals will develop this condition. These risk factors include: 

  1. Age: The risk tends to increase with age as degenerative changes in the electrical system of the heart may occur over time. The AV node may also develop fibrosis (thickening and scarring of the tissue). 

  2. Gender: A 1-degree AV block is generally more common in males due to the increased release of stress hormones.

  3. Athletic Training: Sportspeople who undergo intense training have an increased disease risk. 

  4. Medications: Medications like beta-blockers and calcium channel blockers may affect the electrical conduction system and contribute to heart block

  5. Inflammatory Conditions: The following conditions can lead to inflammation affecting the cardiovascular conduction pathways:

    1. Lyme disease (infection caused by borrelia bacteria)

    2. Chagas disease (an infectious disease from the parasite Trypanosoma cruzi)

    3. Diphtheria (severe bacterial infection from Corynebacterium diphtheriae)

  6. Autoimmune Disorders: Some diseases may increase the risk due to fibrosis in the heart tissue. These conditions include: 

    1. Rheumatoid arthritis (a chronic inflammatory disorder impacting the joints)

    2. Scleroderma (immunological disease causing thickening and hardening of the skin and other body parts)

Prevention of First-Degree Heart Block

People with congenital heart block are at a significantly increased risk of acquiring the condition. However there are methods to prevent its progression. Tips for prevention of first-degree heart block include: 

  1. Regular Exercise: Engaging in consistent physical activity can help maintain a healthy heart and avoid AV block. People should get at least 150 minutes of moderate aerobic workout a week.

  2. Heart-Healthy Nutrition: Individuals should eat a balanced diet rich in fruits, vegetables, lean proteins, and whole grains. Avoiding trans and saturated fats, cholesterol, salt, and added sugars.

  3. Quitting Tobacco Use: Smoking is a significant risk factor for heart disease. Giving up its consumption can improve cardiac health significantly.

  4. Limit Alcohol: Excessive liquor consumption can affect heart rhythm. Therefore, individuals should consume it in moderation.

  5. Stress Management: Chronic stress may contribute to heart problems. Techniques like meditation, deep breathing, and exercise can help reduce the same. It also includes getting 7 to 9 hours of sleep every night. 

  6. Medication Management: People on medicines that can affect heart rhythm (like beta-blockers) should discuss the potential side effects with their doctor. 

  7. Regular Health Check-ups: Getting routine evaluations can help detect problems early, including conditions that might lead to heart block. 

Diagnosis of First-Degree Heart Block

Typically, identification of the condition involves a first-degree heart blockECG to assess the heart. It also includes other key steps. The following is a general outline for the evaluation process:

  1. Medical History: The initial step often includes understanding the health history. The doctor will ask the patient about their symptoms, family history of heart disease, and other relevant issues. 

  2. Physical Examination: During a thorough vital exam, the healthcare professional will observe the heart and check for signs of cardiac problems.

  3. Electrocardiogram (ECG): It is a primary diagnostic tool that records the electrical activity of the heart. It shows disturbances in the sinus rhythm (heartbeat where electrical stimuli begin at the sinus node) and heart structure. The sinus rhythm with 1st-degree AV block shows a prolonged PR interval (greater than 0.20 seconds). This indicates a delay in the electrical conduction from the atria to the ventricles. 

Preparation for Doctor Consultation

Preparing for a health appointment for first-degree heart block involves several steps to ensure the patients get appropriate assessment. The investigative prerequisites include: 

  1. Medical Documentation: Compile a detailed health profile, including previous diagnoses, treatments, and surgeries. Note any family history of heart disease or related conditions.

  2. Symptoms: Keep a record of the potential symptoms, even if they seem unrelated. This should include their frequency, duration, and what seems to trigger or alleviate them.

  3. Current Medications: It is essential to provide a complete list of all ongoing medicines, including over-the-counter drugs and supplements. Some of these can affect heart rhythm or interact with potential treatments for heart block.

  4. Enlist Questions: Prepare a list of queries for the doctor. This may revolve around diagnosis, treatment options, lifestyle changes, prognosis, and any further tests or follow-ups required.

  5. Support Person: A family member or friend can offer support during the appointment. They can help remember the information provided during the consultation and ask further questions.

Expectations During the Evaluation

During a consultation for first-degree AV block, the doctor may ask various questions to understand the condition better and tailor the treatment plan. These questions may include:

  1. Have you experienced symptoms such as shortness of breath, dizziness, or fainting?

  2. When did you first notice these symptoms?

  3. How often do these symptoms occur, and how long do they last?

  4. Does anything seem to improve or worsen these symptoms? 

  5. Do you have any other medical conditions, especially heart-related issues?

  6. Have you had any previous heart surgeries or procedures?

  7. Are you taking any medications, including over-the-counter drugs and supplements?

  8. Is there a history of heart disease or related conditions in your family?

  9. Do you smoke or consume alcohol? If so, how often?

  10. Have your symptoms affected your ability to carry out daily activities or exercise?

Patients should be prepared to answer these questions. 

Questions to Ask the Doctor 

When consulting a doctor about first-degree heart block, it is important to ask questions that help patients understand their condition and the management plan. Here are some key questions individuals might consider asking:

  1. Can you explain what first-degree heart block is and how it affects my heart?

  2. Is my condition likely to progress or worsen over time?

  3. What symptoms should I be aware of or monitor for?

  4. Are there any lifestyle changes to help manage my condition?

  5. Will I need any treatment or medication for first-degree heart block?

  6. Are there any risks or side effects associated with the intervention?

  7. What tests will be required to monitor my heart block? 

  8. Will I need any special preparations during the diagnostic procedures? 

  9. What is the long-term outlook for someone with first-degree heart block?

  10. Is there a risk of developing more serious heart conditions?

  11. When should I seek immediate medical attention?

Patients should not hesitate to ask any other questions they may have. 

Treatment for First-Degree Heart Block

Most cases of first-degree heart block are asymptomatic and do not typically cause significant complications. As a result, they do not require treatment. However, regular evaluation is essential, as patients with it have a higher risk of developing second or third-degree atrioventricular block.

Sometimes, patients may have a PR interval greater than 0.30 seconds and experience symptoms of conduction disorder. In such severe cases, patients may need a permanent pacemaker. This small, battery-powered device sends electrical pulses to the heart.  

Complications of First-Degree Heart Block

A first-degree AV block is generally not serious. Patients can lead normal lives without symptoms, provided the condition does not progress. If the problem worsens, it may cause complications such as: 

  1. Injury from Fainting: In AV block, the heart may not pump blood as effectively, which can decrease the blood flow to the brain. This reduction can cause fainting and patients might injure themselves during the fall. 

  2. Low Blood Pressure (Hypotension): A slower heart rate can mean less blood is transmitted through the body. This can decrease the blood pressure, leading to dizziness and weakness. 

  3. Heart Attack (Myocardial Infarction): In severe cases, it can affect blood flow to a part of the heart. This damages the cardiac muscle and enhances the risk of myocardial infarction. 

  4. Internal Organ Damage: Prolonged periods of low blood flow can lead to inadequate oxygenation of the organs. This can damage body parts like the kidneys, brain, and liver.

When to See a Doctor?

Anyone who experiences symptoms of heart block should consult their doctor promptly. Signs that require medical attention include: 

  1. Unusual fatigue

  2. Difficulty breathing

  3. Reduced ability to exercise

  4. Feelings of weakness, dizziness, or episodes of fainting 

  5. Disorientation or confusion 

Diet for First-Degree Heart Block

For individuals with or at risk of first-degree AV block, a heart-healthy diet is typically recommended. This diet can help manage overall cardiac health and reduce the risk of disease progression. Some key dietary guidelines include:

  1. Fruits and Vegetables: These are rich in vitamins, minerals, and fibre and low in calories, which can help maintain a healthy heart. Thus, ensure appropriate consumption of these.

  2. Whole Grains: Unlike refined grains they provide more fibre, which can help lower cholesterol and improve cardiovascular health. Examples include oatmeal, brown rice, barley, whole-grain pasta, etc.

  3. Low-fat Protein Sources: Lean meats, poultry, fish like salmon, rich in omega-3 fatty acids, low-fat dairy products, and legumes are better protein sources. 

Some foods that must be limited or avoided for a healthy heart include: 

  1. Unhealthy Fats: Reducing intake of saturated and trans fats is crucial to lower blood cholesterol along with the risk of heart disease.

  2. Salt Intake: Too much sodium can result in high blood pressure. Eating fresh foods and meals cooked at home can help control it significantly.


First-degree heart block is a mild heart rhythm irregularity that is often asymptomatic and usually does not need treatment. It is characterised by a delay in electrical signals in the heart, seen as a prolonged PR interval on an ECG. Regular monitoring is important as it poses minimal risk but can occasionally progress to more serious conditions.

HexaHealth can help you with first-degree AV block by providing access to comprehensive information. Our experts offer consultations to diagnose and manage the disease, promoting heart health. Moreover, we can help you connect with top doctors for regular monitoring and advice. So what are you waiting for? Get in touch with us TODAY! 

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FAQs for First Degree Heart Block

First-degree heart block is a mild form of cardiac rhythmic disorder with delayed electrical signals between atria and ventricles. It is typically detected by a prolonged PR interval on an electrocardiogram. However, it is usually harmless, asymptomatic and doesn’t require treatment.


 First-degree AV block can be caused by various factors, including:

  1. Heart disease

  2. Congenital heart defects

  3. Certain medications

  4. Open heart surgery 

It is often discovered incidentally during ECG tests.


First-degree heart block typically does not cause noticeable symptoms in most individuals. It is usually an incidental finding during routine electrocardiograms. In rare cases, if first-degree heart block symptoms occur, they might include:

  1. Fatigue

  2. Dizziness

  3. Lightheadedness

  4. A feeling of skipping heartbeats


First-degree heart block ECG is often used for diagnosis. It measures the electrical activity of the heart. The diagnosis is confirmed when the ECG shows a prolonged PR interval, indicating a delay in the transmission of electrical signals between the atria and ventricles.


Yes, some images and diagrams illustrate first-degree heart block, typically showing ECG tracings. These images highlight the prolonged PR interval (the key ECG finding in this condition). It demonstrates the electrical delay in the heart.


The , first-degree heart block appears on ECG as a prolonged PR interval longer than 0.20 seconds. This indicates a delay in the electrical signal passing from the atria to the ventricles, but every signal eventually reaches the ventricles.


1st degree heart block is generally not dangerous. However, it requires monitoring, as it occasionally indicates a higher risk of developing more serious heart rhythm issues. This is especially true if underlying heart conditions are present.


Treatment for 1st-degree AV block usually isn’t necessary, as the condition is often asymptomatic. Management primarily involves regular monitoring to check for any progression to more serious heart block or the development of other heart-related issues.


If medicines cause a heart block, changing them can sometimes help stop the condition. However, for first-degree heart block, treatment is generally not required. 


Lifestyle changes can help manage overall heart health, which may benefit those with first-degree heart block. This includes:

  1. Maintaining a healthy diet

  2. Regular physical activity

  3. Avoiding smoking

  4. Limiting alcohol consumption

  5. Managing stress


To reduce heart block naturally, focus on a heart-healthy lifestyle:

  1. Eat a balanced diet with vegetables, fruits, and whole grains

  2. Exercise regularly

  3. Avoid smoking

  4. Limit alcohol

  5. Manage stress

  6. Maintain a healthy weight

These habits can improve overall heart health.


First-degree heart block typically does not always require medical intervention, especially if it is asymptomatic. However, regular monitoring is important to track any changes in the heart rhythm. It also helps check for the development of more significant heart-related issues.


Yes, first-degree heart block can progress to higher degrees, such as second or third-degree heart block. In these conditions, the electrical conduction between the atria and ventricles becomes more severely impaired, potentially requiring medical intervention.


First-degree heart block typically does not require treatment. It can be reversible if caused by medications or underlying medical issues. However, in some cases, it may persist.


Yes, a 1-degree AV block can be monitored through regular check-ups, including ECGs. These check-ups help track the condition’s stability and ensure any progression to higher-degree blocks is detected early. This allows for appropriate medical management if needed.


Measures to prevent the causes of first-degree AV block include: 

  1. Engage in regular physical activity 

  2. Adopt a heart-healthy diet 

  3. Quit smoking 

  4. Restrict alcohol consumption 

  5. Employ stress management techniques 

  6. Schedule routine health examinations 


First-degree heart block generally has minimal impact on daily life and activities. It may go unnoticed, as symptoms are rare. In most cases, individuals can continue their routines without significant limitations or discomfort.


1st-degree heart block is not considered serious. It often does not cause symptoms and does not require immediate treatment. However, it may warrant monitoring, as it can progress to more severe heart block in rare cases.


First-degree AV block may resolve if medications or temporary factors cause it. However, it might persist if it is due to structural heart issues. 



All the articles on HexaHealth are supported by verified medically-recognized sources such as; peer-reviewed academic research papers, research institutions, and medical journals. Our medical reviewers also check references of the articles to prioritize accuracy and relevance. Refer to our detailed editorial policy for more information.

  1. Prabhakaran D, Jeemon P, Roy A. Cardiovascular Diseases in India. Circulation. 2016 Apr 19;133(16):1605–
  2. Oldroyd SH, Makaryus AN. First Degree Heart Block [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2020. link
  3. Cleveland Clinic. Heart Block | Cleveland Clinic [Internet]. Cleveland Clinic. 2019. link
  4. Ibe U. 1st degree heart block: Causes, symptoms, and treatment [Internet]. 2022. link
  5. Understanding First-Degree Heart Block [Internet]. Saint Luke’s Health System. link
  6. Ibe U. Heart Block: Types, Causes, Symptoms, Treatment [Internet]. Healthline. 2022. link
  7. Mayo Clinic Staff. 8 steps to a heart-healthy diet [Internet]. Mayo Clinic. 2022. link
Disclaimer: The information provided here is for educational and learning purposes only. It doesn't cover every medical condition and might not be relevant to your personal situation. This information isn't medical advice, isn't meant for diagnosing any condition, and shouldn't replace talking to a certified medical or healthcare professional.


Dr. Aman Priya Khanna

Dr. Aman Priya Khanna

MBBS, DNB General Surgery, Fellowship in Minimal Access Surgery, FIAGES

12 Years Experience

Dr Aman Priya Khanna is a well-known General Surgeon, Proctologist and Bariatric Surgeon currently associated with HealthFort Clinic, Health First Multispecialty Clinic in Delhi. He has 12 years of experience in General Surgery and worke...View More


Sparshi Srivastava

Sparshi Srivastava

B.Tech Biotechnology (Bansal Institute of Engineering and Technology, Lucknow)

2 Years Experience

An ardent reader, graduated in B.Tech Biotechnology. She was previously associated with medical sciences secondary research and writing. With a keen interest and curiosity-driven approach, she has been able to cont...View More

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