Third degree AV block

Third-degree AV block, also known as complete heart block, is a medical condition in which the electrical signals generated in the atria of the heart cannot propagate to the ventricles due to a complete block at the atrioventricular (AV) node. This results in the atria and ventricles beating independently of each other. Third-degree AV block is a serious condition that can lead to significant cardiac complications, including heart failure, syncope, and sudden cardiac death.

Causes

Third-degree AV block can be caused by a variety of factors, including:

• Ischemic heart disease: This is the most common cause, where reduced blood flow damages the heart's electrical system.
• Cardiomyopathy: Diseases of the heart muscle can lead to AV block.
• Congenital heart defects: Some people are born with conditions that predispose them to AV block.
• Medications: Certain drugs, especially those that affect the heart's electrical activity, can cause AV block.
• Lyme disease: This infectious disease can occasionally affect the heart's electrical system.

Symptoms

Symptoms of third-degree AV block may include:

• Fatigue
• Dizziness
• Fainting spells (syncope)
• Shortness of breath
• Chest pain

Diagnosis

Diagnosis of third-degree AV block typically involves:

• Electrocardiogram (ECG or EKG): This test records the electrical activity of the heart and can show the presence of AV block.
• Holter monitor: A portable device worn for 24 hours or more to record the heart's electrical activity over time.
• Echocardiogram: An ultrasound of the heart that can assess structural heart problems which may cause AV block.

Treatment

Treatment for third-degree AV block often involves the implantation of a pacemaker, a device that electrically stimulates the heart to maintain an adequate heart rate. In some cases, treatment of the underlying cause (e.g., medication adjustment, treatment of heart disease) may also be necessary.

Prognosis

With appropriate treatment, most individuals with third-degree AV block can lead normal lives. However, the condition does require lifelong monitoring and management to prevent complications.

Prevention

Prevention of third-degree AV block involves managing risk factors for heart disease, such as controlling high blood pressure, maintaining a healthy weight, exercising regularly, and not smoking.