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Bundle branch block is a condition where there is a delay or obstruction along the pathway that carries electrical impulses for the heartbeat. This delay can make it more challenging for the heart to effectively pump blood to the rest of the body. It can also result in an irregular heart rhythm. The blockage can occur on either the left or right side of the heart’s lower chambers (ventricles).
Normally, electrical impulses travel through bundle branches, causing both ventricles to contract simultaneously. However, in the presence of bundle branch block, the electrical signal is delayed, causing one ventricle to contract later than the other.
Treatment for bundle branch block may not always be necessary. When treatment is required, it primarily involves managing the underlying health condition, such as heart disease, that led to the development of bundle branch block.
Symptoms
Bundle branch block can be asymptomatic, but when symptoms do occur, they can manifest as follows:
- Dizziness
- Fainting (syncope)
- Sensation of impending fainting (presyncope)
If bundle branch blockage affects both sides, additional symptoms may arise:
- Irregular heartbeat (arrhythmia)
- Difficulty breathing (dyspnea)
- Slow heart rate (bradycardia)
If you experience fainting, it is important to seek medical attention to exclude any underlying serious conditions. For individuals with pre-existing heart disease or a known diagnosis of bundle branch block, it is advisable to consult with a healthcare provider regarding the recommended frequency of follow-up visits. Regular check-ups can help monitor the condition and ensure appropriate management.
Causes
When the electrical impulses in the heart muscle are disrupted, such as due to a heart attack, the heart’s contraction pattern can become irregular. This disruption often occurs in the pathway of the electrical signals, which includes two branches known as the right and left bundles. If one or both of these bundles are damaged, the impulses can be blocked, leading to an irregular heartbeat. The specific causes of bundle branch blocks can vary depending on whether the left or right bundle branch is affected, although in some cases, the cause may remain unknown.
Common causes of a bundle branch block may include:
- Left bundle branch block
- Myocardial infarction
- Myocarditis
- Cardiomyopathy
- Hypertension
- Right bundle branch block
- Pulmonary embolism
- Myocardial infarction
- Congenital heart disease, such as atrial septal defect
- Pulmonary hypertension
- Myocarditis
- Chronic obstructive pulmonary disease (COPD)
Risk factors
Anyone can have a bundle branch block. However, certain risk factors may increase one’s risk, such as:
- Aging: As the person grows older, the higher is the risk of developing bundle branch block. It may affect about 0.8% of people at age 50 and up to 11.3% of people by age 80.
- Underlying health issues: People with other health issues such as heart disease and high blood pressure are more susceptible of bundle branch block.
Diagnosis
The diagnosis of a bundle branch block usually depends on where the block is located. People with right bundle branch block and are otherwise healthy and may not require a thorough testing. However, a complete medical examination is required if one has a left bundle branch block.
To confirm the diagnosis, these tests may be required:
- Electrocardiogram (ECG or EKG): An EKG might reveal which side of the heart is affected by the bundle branch block. During an EKG, electrodes are attached to the skin of the chest area. One must remain motionless as a computer tracks the electrical impulses that go through the heart. The electrical activity of the heart is measured. It can demonstrate how well the heart is pumping.
- Echocardiogram: This test can help identify the cause of the bundle branch block. It can also screen for cardiovascular disease and other underlying diseases. During an echo, a hand-held wand is used to examine the heart. It uses sound waves to provide detailed pictures of the heart and its valves. It can demonstrate the structure and thickness of the cardiac muscle.
Treatment
The treatment for bundle branch block depends on the exact symptoms and concurrent heart diseases. If there are no symptoms, treatment may not be necessary. Other concerns along with bundle branch block, such as high blood pressure or heart failure symptoms, may necessitate treatment.
- Medications: The treatment for a heart condition that causes bundle branch block may involve the use of medications to lower high blood pressure and alleviate symptoms related to heart failure.
- Surgeries and other procedures: If you have bundle branch block and a history of fainting, your healthcare provider may recommend a pacemaker, which is a small device implanted under the skin of the upper chest. It is connected to the right side of the heart using two wires and releases electrical impulses as needed to maintain a regular heartbeat. However, if you also have low heart-pumping function along with bundle branch block, you may require cardiac resynchronization therapy (biventricular pacing). This treatment is similar to a pacemaker but involves an additional wire connected to the left side of the heart, enabling the device to synchronize both sides and promote more organized and efficient contraction of the heart chambers.
