Left Posterior Fascicular Block

Left posterior fascicular block (LPFB) is a blockage in your left posterior fascicle that keeps it from sending electrical signals to part of your heart. Signals can’t reach the left posterior part of your lower left heart chamber, so other signaling cells take over. This changes where the electrical impulse goes and delays it.

Usually, signal carriers (fascicles) around the front and back (posterior) of your left ventricle work together. They tell your left ventricle to beat. With a block in your back fascicle, your front one steps in to make your left ventricle beat.

Left posterior fascicular block (hemiblock) can be partial or complete. It can happen on and off or without a break.

LPFB is very rare in most people. It’s more common in people with heart conditions.

Many people who have left posterior fascicular block also have a right bundle branch block. This involves blocked electrical signals on the right side of your heart. When these types of blocks occur together, you’re at a higher risk of fatal cardiac events like complete heart block.

Symptoms of left posterior fascicular block

Typically, left posterior fascicular block doesn’t cause symptoms. People may have symptoms from the disease that’s causing it, which may include:

• Chest pain
• Shortness of breath
• Heart palpitations
• Fainting
• Fatigue

LPFB causes

Left posterior fascicular block happens when you have heart damage. The main causes of this damage are heart diseases and conditions, like:

• Coronary artery disease: Lack of blood flow to your heart due to clogged arteries can damage your heart. This is the most common condition at the root of the problem.
• Cardiomyopathy: These are conditions that make your heart muscle stiff, thick or enlarged.
• High blood pressure: Unmanaged blood pressure makes it harder for your heart to pump blood. This can weaken your heart muscle.
• Aortic valve disease: This may include issues like leaks or narrowing in your aortic valve.
• Lenègre disease: This is a condition you inherit. Scarring affects the conduction of electrical signals in your heart.
• Lev’s disease: Nerve fibers in your heart become scarred. This makes them less able to send electrical signals.

How doctors diagnose left posterior fascicular block

Healthcare providers diagnose LPFB with an electrocardiogram (ECG/EKG). This test measures your heart’s electrical activity.

They may also perform an EKG while you’re physically active to measure your heart’s activity under stress. This is an exercise stress test. Sometimes, it shows left posterior fascicular blocks that didn’t show up on the EKG you had while at rest.

Providers have diagnostic criteria for left posterior fascicular block. They look for very specific LPFB patterns in your EKG results. The patterns represent your heart’s electrical activity.

To be thorough, your provider will ask about your medical history and perform a physical exam.

How is it treated?

Left posterior fascicular block treatment manages the condition that’s causing the block. For heart diseases like coronary artery disease, healthcare providers use various treatments. These include:

• Lifestyle changes
• Medicines
• Minimally invasive procedures
• Surgery

If you have LPFB and right bundle branch block, your provider may recommend a pacemaker. This implanted device monitors your heart’s electrical activity. It sends electrical signals so your ventricles contract together.

If you have left posterior fascicular block without other heart conditions, you won’t need treatment.

When should I see my healthcare provider?

Talk to your healthcare provider if you think you have heart disease.

You may want to ask your provider:

• Do I need to be concerned about LPFB?
• What’s the best treatment for the heart issue that’s causing it?
• How often do I need checkups?

What can I expect if I have this condition?

Most often, LPFB and right bundle branch block occur together. If you have a heart attack, having left posterior fascicular block and right bundle branch block increases your risk of death. Sometimes, a person with both blocks can develop a complete block of electrical impulses in their ventricles. The outlook for this condition is poor.

If you don’t have right bundle branch block or underlying heart disease, your life expectancy doesn’t change with LPFB.

Can LPFB be prevented?

To prevent left posterior fascicular block, you need to prevent the heart conditions that cause it. Routine check-ups with your primary care provider can find heart problems early and prevent serious outcomes.

If you have an existing heart condition, follow your provider’s instructions. This can help you avoid complications like a left posterior fascicular block.