Bundle branch block: symptoms, causes and treatments

The heart has specialized tissue capable of transmitting electrical impulses. This is divided into two branches (one right and one left) to cover both sides of the organ. Therefore, bundle branch block is a disease in which some of these structures do not function correctly.

This results in the inability of the heart to contract with a normal rhythm, which increases the possibility of cardiovascular complications. Are you interested in knowing a little more about this condition? Keep reading!

What causes bundle branch block?

The conditions that most often cause bundle branch block are:

  • Myocardial infarction.
  • Arterial hypertension.
  • Myocarditis.
  • Cardiomyopathies.

In most cases, the blood supply to the tissue that is responsible for transmitting electrical impulses in the heart is poor, as happens in a heart attack. Here, the rupture of an atheroma plaque can obstruct the blood flow of the coronary arteries, which carry oxygen and nutrients to the myocardium.

The latter causes progressive tissue deterioration which, in many cases, is irreversible. For this reason, bundle branch block is a common complication of some cardiovascular events.

Myocarditis, on the other hand, is inflammation of the myocardium that occurs as a result of infection. One of the microorganisms involved is the Trypanosoma cruzi, causal agent of Chagas disease.

Cardiovascular events that affect the myocardium can have bundle branch block as a complication.

Find out more: Heart disease doesn't just affect the heart

Symptoms of bundle branch block

There are several types of bundle branch block, depending on the characteristics of the heart rhythm that result from it. Fortunately, most patients have mild blockage and do not develop symptoms. In these cases, it is common for the diagnosis to be made as part of a routine medical evaluation.

However, those who develop obvious signs may have palpitations and fainting spells (syncope). They usually have other associated cardiovascular or metabolic diseases, such as high blood pressure or diabetes mellitus.

Depending on the degree of involvement of the different organs (such as the kidneys) there could be more symptoms. In severe cases, the heart is unable to perform its function correctly, which will generate hemodynamic instability. This includes a progressive decrease in blood pressure, which if not corrected can lead to shock.

How can it be diagnosed?

The doctor could arrive at the diagnosis with the combination of clinical elements and complementary tests. A thorough physical examination may detect the heart rhythm disturbance, provided it is significant.

Anyway, confirmation is made by an electrocardiogram. This is characterized by making a measurement of the electrical activity of the heart, which includes the frequency with which the heartbeat appears. This last characteristic is altered in patients with bundle branch block.

It is also possible to perform an echocardiogram, which is a more expensive imaging technique and can only be performed by a specialist. The advantage of its use is that allows determining structural alterations that explain the origin of the disease.

Keep reading: How to diagnose heart disease?

Treatments for bundle branch block

There are several therapeutic modalities, depending on the clinical severity and the risk of developing fatal arrhythmias. Next we will comment on the most important ones in general.


As we said before, most of the cases correspond to asymptomatic patients. For this reason, the treating professional does not usually send something specific for bundle branch block. However, it is necessary to indicate drugs against the cause of the disease.

For example, in the case of a hypertensive patient the prescription of antihypertensive and diuretic drugs is common. They are a large group of drugs and the differences lie in the mechanism of action.

Some of the most widely used antihypertensives are losartan, amlodipine, and enalapril. Within the group of diuretics, hydrochlorothiazide and furosemide stand out.


Pacemakers are devices that take command of your heartbeat to give your heart regularity.

It's about a device capable of adjusting the electrical activity of the heart to a normal rhythm. Although it was originally a costly, problematic treatment with several adverse effects, today it is considered safe and easy to maintain.

According to a publication of the Spanish Heart Foundation, there are two types of pacemakers: temporary and permanent. The latter require subcutaneous implantation, for which the doctor must also insert a wire through one of the veins that drain on the right side of the heart.

Cardiac resynchronization therapy

This treatment is reserved for more severe cases in which there is poor coordination between the activity of the left side and that of the right side of the heart. According to a Mayo Clinic publication, the device used is also known as biventricular pacemaker.

The benefit is so much that some models include an implantable cardioverter defibrillator. This means that, in emergency cases, in which the heart rhythm changes significantly, the device is capable of emitting an impulse capable of defibrillating.

Complications can always be prevented

Due to the possibility of developing fatal cardiovascular events, it is recommended that patients with risk factors attend a routine medical consultation. Family doctors and internists are a valid option. In some cases, these may refer you to a cardiologist.