What Is a Bundle Branch Block

A bundle branch block is a blockage in which the flow of electrical impulses to the ventricles—either the left or the right—is partially or totally interrupted. These impulses are responsible for the muscular contractions that generate heartbeats. This blockage ends up making it difficult to pump blood to the rest of the body.

Depending on the damaged branch, the block can be left or right.

Bundle Branch Block Symptoms

A bundle branch block is a condition that can occur without obvious symptoms, especially when it is not associated with other heart conditions. However, in some cases, it can cause signs such as:

• Slow heart rate
• Arrhythmia
• Loss of consciousness

A bundle branch block does not always mean the presence of a serious disease, but when it appears with other symptoms or conditions like coronary disease, hypertension, or cardiomyopathies, it can reflect a deterioration in heart function.

This can result in a reduction in the heart’s pumping efficiency, which contributes to symptoms of heart failure such as shortness of breath or swelling in the extremities.

Right Bundle Branch Block

A right bundle branch block occurs when there is an interruption or delay in electrical conduction through the right bundle branch of the His bundle. This causes the right ventricle to activate later than the left one.

This condition can be benign, especially in young and healthy people, although it can also be related to lung diseases, pulmonary embolism, or structural heart disease.

Left Bundle Branch Block

A left bundle branch block is a conduction abnormality in the left bundle branch of the heart’s conduction system, which causes a delay in the activation of the left ventricle. This results in desynchronization between the ventricles and can affect the efficiency of the heart’s pumping.

Unlike a right bundle branch block, a left bundle branch block is usually more associated with significant heart diseases such as ischemic heart disease or heart failure, so its presence generally has greater clinical relevance.

Diagnosing a Bundle Branch Block

The diagnosis of a bundle branch block is made primarily through an electrocardiogram, which can identify characteristic abnormalities in the heart’s electrical conduction. Here, the key finding is the widening of the QRS complex to more than 120 milliseconds, which refers to the time in milliseconds that the ventricles take to contract.

In addition to the electrocardiogram, the doctor will evaluate the patient’s clinical history, current symptoms, and other cardiovascular risk factors to determine the possible cause of the block.

Sometimes, additional studies may be used to evaluate the structural and functional status of the heart, especially if the block is suspected to be associated with an underlying heart condition. These studies may include echocardiograms, stress tests, a cardiac MRI, or electrophysiology studies. All of these studies will help the cardiologist determine if the block is isolated and benign or if it is related to a more serious condition.

Right Bundle Branch Block Treatment

In most cases, a right bundle branch block does not require specific treatment, especially if it is considered an isolated finding and the patient does not have symptoms of another associated heart disease.

It is common for this condition to be detected incidentally on an electrocardiogram performed for routine purposes or another reason, and only periodic checkups with the cardiologist are indicated.

But if the right bundle branch block appears with other conditions, the underlying cause must be treated.

Left Bundle Branch Block Treatments

A left bundle branch block has greater clinical implications because it is often associated with structural heart diseases. Here, the treatment focuses primarily on the underlying disease.

On the other hand, if this block causes a significant desynchronization in the contraction of the ventricles and the patient has symptoms or a reduced ejection fraction, a cardiac resynchronization therapy may be indicated. This is a device similar to a pacemaker that helps improve the coordination of the heartbeat and the function of the heart.

Medications may also be required to control blood pressure, prevent cardiovascular events, and manage heart failure.

At the Arrhythmia Clinic at ABC Medical Center, we can provide you with specialized care. Contact us!