- 7/24 Live Call Center
Last Updated on November 25, 2025 by Ugurkan Demir
Third-degree AV block, also known as complete heart block, is a serious condition. It happens when electrical signals from the heart’s atria can’t reach the ventricles. This can cause a very slow and irregular heart rate, which is dangerous.
At Liv Hospital, we know how critical it is to treat third degree heart block quickly. Our approach focuses on the patient, giving them the support and guidance they need. In this article, we’ll share 7 key facts about third-degree AV block. This will help readers understand the condition and how to manage it.
Third-degree AV block, or complete heart block, is a serious issue with the heart’s electrical system. It means there’s no flow of electrical signals from the atria to the ventricles. This causes a problem with the heart’s rhythm.
Third-degree AV block means the atria and ventricles beat on their own. This is because there’s no signal going through the atrioventricular node (AVN). It’s also called complete heart block (CHB). The name shows how serious it is, with no electrical signals getting through.
Complete heart block is different from first and second-degree AV blocks. In first-degree AV block, signals get to the ventricles but are delayed. Second-degree AV block means some signals are blocked. But third-degree AV block is when there’s no signal at all going through the AV node.
Third-degree AV block gets more common with age, hitting people over 70 hard. It often affects those with heart disease or who’ve had heart surgery. Knowing who’s at risk helps in taking steps to prevent it.
The heart’s electrical system is key to keeping a regular heartbeat. It ensures the heart beats in sync, helping blood flow well around the body.
To grasp how complete AV block impacts the heart, we must first look at the normal heart rhythm pathways. The journey starts in the sinoatrial (SA) node in the right atrium. This node is the heart’s natural leader, sending out signals that make the heart contract.
The signal from the SA node moves through the atrial tissue to the atrioventricular (AV) node. This node is between the atria and ventricles. It pauses the signal, letting the atria fully contract before the ventricles contract. This pause is essential for the heart to work right.
After the AV node, the signal goes down the bundle of His. It splits into the left and right bundle branches. Then, it reaches the Purkinje fibers, spreading the signal to the ventricles, making them contract.
In complete AV block, or third-degree AV block, the pathway between the atria and ventricles is blocked. This leads to AV dissociation, where the atria and ventricles beat on their own.
The SA node keeps sending signals for the atria to contract. But these signals can’t get to the ventricles because of the block. So, the ventricles must find another way to beat, using an escape pacemaker.
Without normal AV conduction, a ventricular escape rhythm takes over. This rhythm comes from a pacemaker below the block, usually in the AV junction or ventricles.
The heart rate in third-degree AV block is significantly slower, usually between 40-60 beats per minute. This slow rate can cause symptoms like fatigue, dizziness, and shortness of breath.
Understanding the heart’s electrical system and how complete AV block affects it is key. The av block 3 or third-degree AV block is a serious issue. It needs quick medical care and often requires a pacemaker to fix the heart rate and improve blood flow.
It’s important to know what causes full heart blockage. This condition, also known as third-degree atrioventricular (AV) block, happens when the electrical signals between the heart’s upper and lower chambers are blocked. This can be due to several factors that harm the heart’s electrical system.
As we get older, our heart’s electrical pathways can wear out. This can lead to third-degree AV block. This problem is more common in older people and often goes hand in hand with other heart issues.
Heart attacks and coronary artery disease can also cause full heart blockage. Damage from a heart attack can mess up the heart’s electrical system. Coronary artery disease can reduce blood flow to the heart, raising the risk of third-degree AV block.
Some medicines can also lead to complete heart block. These include drugs that slow the heart rate or affect its electrical signals. Examples include beta-blockers, calcium channel blockers, and anti-arrhythmic medications. These can cause third-degree AV block, mainly in people with existing heart problems.
Other things can also cause full heart blockage. These include congenital heart defects, inflammatory heart diseases, and infections that affect the heart. Surgical complications during heart surgeries can also lead to complete AV block.
In summary, full heart blockage is a complex issue with many possible causes. Knowing these causes is key to diagnosing and treating third-degree AV block properly.
Knowing the signs of third-degree heart block can save lives. It’s important to recognize symptoms that show a serious heart issue.
Third-degree heart block can make daily life tough. Symptoms include fatigue, dizziness, and shortness of breath. These happen because the heart doesn’t pump well, leading to less blood and oxygen for the body.
Fatigue is a big problem for those with third-degree heart block. It can be mild or very severe. Dizziness or feeling lightheaded also happens because of less blood to the brain.
Syncope, or fainting, is a serious symptom of third-degree heart block. It happens when the brain doesn’t get enough blood. Pre-syncope, feeling like you’re going to faint, is also a warning sign. These signs mean you need to see a doctor right away.
Some symptoms need urgent medical help. These include severe chest pain, severe shortness of breath, or loss of consciousness. In bad cases, third-degree heart block can cause cardiac arrest, a serious condition needing quick CPR and doctor help.
| Symptom | Description | Severity |
| Fatigue | Feeling tired or exhausted | Mild to Severe |
| Dizziness | Feeling lightheaded | Mild to Severe |
| Shortness of Breath | Difficulty breathing | Mild to Severe |
| Syncope | Fainting or loss of consciousness | Severe |
| Cardiac Arrest | Sudden loss of heart function | Life-Threatening |
An electrocardiogram (ECG) is key for spotting complete heart block. It shows the heart’s electrical activity. This helps doctors see if there’s a block and how serious it is.
A complete heart block ECG shows AV dissociation. This means the heart’s upper and lower parts beat on their own. The P waves and QRS complexes don’t match up, with P waves often going through QRS complexes.
In third-degree AV block, the heart’s upper rhythm starts normally. But, the electrical signal gets blocked, causing the heart’s upper and lower parts to beat out of sync.
Key features include:
While the ECG is the main tool for diagnosing complete heart block, other tests are used too. These help find the cause and check how well the heart works. Tests include:
These tests help doctors confirm the diagnosis and plan the best treatment for complete heart block.
Understanding third-degree atrioventricular block is key to managing it. We’ll cover the main ways to treat this serious heart issue. This includes both immediate care and long-term strategies.
When symptoms of complete heart block appear, quick action is needed. The main goal is to get the heart rhythm back to normal and ensure blood flows well. Temporary pacing is often used to control the heart rate until a permanent fix is found.
Emergency care includes:
For most, permanent pacemaker implantation is the best treatment. This surgery puts a pacemaker in to regulate the heart’s rhythm with electrical impulses.
Pacemaker benefits include:
There are many pacemaker types, each suited for different needs. The choice depends on the patient’s condition, lifestyle, and specific needs. The main types are:
We look at several factors when picking a pacemaker. These include the heart’s function, other heart issues, and activity level. Our goal is to find the best pacemaker for each patient to improve their heart health.
Untreated complete AV block can cause severe and dangerous problems. It’s very important to know these risks. Quick medical help can greatly improve a patient’s chances of recovery.
One big danger of untreated complete heart block is bradycardia. This is when the heart beats too slow. It can make it hard for blood to reach important parts of the body, leading to symptoms like dizziness and shortness of breath. If it gets worse, it can even cause cardiac arrest, a serious condition that needs fast medical care.
The chance of sudden cardiac arrest is much higher for those with untreated complete AV block. This shows how urgent it is to get a diagnosis and treatment to avoid such serious problems.
Untreated complete AV block can also cause long-term problems. These include:
| Complication | Description | Impact on Patient |
| Bradycardia | Abnormally slow heart rate | Dizziness, fatigue, shortness of breath |
| Heart Failure | Reduced heart efficiency | Shortness of breath, fatigue, swelling |
| Syncope/Pre-syncope | Episodes of fainting or near-fainting | Risk of injury, decreased quality of life |
After getting a pacemaker, patients with complete AV block do much better. This treatment helps the heart beat more normally, easing symptoms and lowering the risk of serious problems.
Research shows that pacemakers can help patients live longer, feel better, and enjoy a better quality of life. The type of pacemaker and the patient’s health can affect how well they do.
It’s important for patients to follow their doctor’s advice on caring for themselves after getting a pacemaker. This helps ensure the best results.
Getting a third degree heart block diagnosis can change your life. But, with the right steps, you can stay active. Managing this condition means more than just medical care. It also means making big lifestyle changes.
If you have third degree heart block, you need to watch your physical activities. Even with a pacemaker, some exercises might not be safe. It’s important to balance staying healthy with avoiding risks.
Talking to your doctor is key to creating a safe exercise plan. They can help you find activities that are both safe and beneficial.
For many, a pacemaker is a lifesaver. Taking care of it is essential for it to work right.
Important pacemaker care steps include:
Regular monitoring is key to managing third degree heart block. This means regular doctor visits and knowing when to get help fast.
Signs that need quick medical help include:
By staying informed and proactive, you can manage third degree heart block well. This helps you keep a good quality of life.
Third degree heart block, also known as complete heart block, is a serious condition. It needs quick medical help. We’ve talked about how full heart blockage happens when there’s a complete stop in the electrical pathway between the atria and ventricles.
For treating third degree heart block, a permanent pacemaker is often used. This device helps control the heartbeat. It makes sure the ventricles beat at the right rate for the body’s needs.
People with complete heart block must work closely with their doctors. Knowing the causes, symptoms, and treatments helps them stay healthy. This way, they can play an active role in their health and well-being.
We stress the need to see a doctor if symptoms don’t get better or get worse. With the right treatment, people with third degree heart block can live full and happy lives.
Third degree heart block, also known as complete heart block, is a serious condition. It happens when electrical signals from the heart’s atria can’t reach the ventricles. This leads to AV dissociation and often a very slow, irregular heart rate.
Doctors use an electrocardiogram (ECG) to diagnose third degree AV block. The ECG shows signs like AV dissociation and a ventricular escape rhythm. More tests might be needed to confirm the diagnosis.
Symptoms include fatigue, dizziness, shortness of breath, and fainting. In severe cases, it can cause emergency warning signs that need immediate medical help.
Full heart blockage can be caused by age-related degeneration, heart attacks, and coronary artery disease. Certain medications and other factors can also contribute.
The main treatment is a permanent pacemaker implantation. For symptoms, emergency management might be needed. The type of pacemaker depends on individual needs.
Untreated complete AV block can lead to short-term risks like bradycardia and sudden cardiac arrest. It can also cause long-term complications. Prompt treatment with a pacemaker can greatly improve the prognosis.
After the implantation, follow activity recommendations and restrictions. Keep your pacemaker clean and attend follow-up appointments. Know when to seek medical help for unusual symptoms.
First degree heart block delays electrical conduction. Second degree is a partial blockage. Third degree is a complete blockage.
Yes, some medications can affect the heart’s electrical system, causing complete heart block.
AV dissociation is a hallmark of third degree heart block. It means the atria and ventricles beat independently due to the blockage of electrical signals.
