According to standard electrocardiographic (ECG) criteria, up to one-third of individuals with left bundle branch block (LBBB) are misdiagnosed. However, most patients with LBBB do not have underlying heart disease and can be managed effectively without intervention. Patients with LBBB should be monitored for symptoms that indicate the presence of heart failure or ventricular tachyarrhythmias.
Left bundle branch block (LBBB) is a frequent electrocardiographic (ECG) condition reported in patients who have impaired cardiac conduction along both the anterior and posterior left fascicles of the His-Purkinje system. It is often associated with other heart conditions, such as coronary artery disease, cardiomyopathy, and valvular disease.
Patients with LBBB have prolonged QRS complexes without R waves in V1 through V6. The QRS complex is usually wider than 120 ms and sometimes has a slurred ventricular impulse or "sick sinus syndrome-like" appearance.
Electrocardiography (ECG) shows a wide, flat QRS complex with no identifiable P waves and no reciprocal activity between leads V5 and V6. There may be some indication of left ventricular dysfunction from one or more of the following: enlargement of the ventricles, reduced contractility, increased internal resistance, or abnormal wall motion. The presence of LBBB should alert the physician to search for other causes of an abnormal ECG, especially coronary artery disease.
Diagnosis requires finding evidence of delayed activation of the left ventricle on an ECG recording.
The left bundle branch block seldom causes symptoms on its own. However, in certain situations, you may have symptoms such as dizziness. Fainting. Chest pain. Shortness of breath.
People with LBBB are more likely to experience faintings than others. The reason is not clear, but it may be related to increased risk of developing congestive heart failure or arrhythmias. In addition, people with LBBB may require extra attention if they are taking drugs that can cause hypotension (low blood pressure). These include anti-depressants, beta blockers, and calcium channel blockers. Doctors should be made aware of your current medication list before any diagnostic tests are performed so that proper precautions are taken.
LBBB is often a sign of other problems too. For example, if you are experiencing shortness of breath when walking up stairs or exercising then this may be due to coronary artery disease. If you are experiencing dizziness or fainting because of LBBB then you should see a doctor so that appropriate treatment can be given.
Medication, for example, is not used to treat left bundle branch block. Treatment, however, is dependent on your unique symptoms and underlying cardiac issues. For example, if you have a history of heart failure or severe coronary artery disease (CAD), your doctor may recommend medications to control your blood pressure and cholesterol or prevent future problems with these organs.
The LAFB does not create any symptoms on its own. If action potentials do not go through the regular LAFB to the left ventricular myocardium to elicit contraction of heart muscle cells, they will ultimately reach there via the posterior fascicle and right bundle branch. When this happens, symptoms such as chest pain, shortness of breath, and dizziness may occur if enough nerve tissue is affected.
If you have LAFB, your doctor will be able to tell by looking at your history and performing a physical examination. Your doctor may also suggest tests such as an electrocardiogram (ECG) or cardiac catheterization to determine whether there are any other problems with your heart rhythm that might need treatment other than medication.
There are several things that can cause symptoms like those in LAFB. For example, you may have symptoms if you have an acute coronary event such as when you have a heart attack or experience a severe heart attack symptom. You may also have symptoms if you have diseases of the lungs (such as pneumonia), kidneys (such as nephritis), or brain (such as cerebrovascular disease or Alzheimer's disease). Depression or anxiety can also cause symptoms. If you are having symptoms that last more than one week or so or change in intensity or type, see your doctor to make sure that no other problem has been missed.
Unfortunately, LBBB cannot be reversed. In your instance, the total risk of cardiovascular morbidity or mortality should be quite minimal in the absence of significant structural heart disease and symptoms. In people with LBBB, the main concern is not whether or not they will develop heart failure. Instead, the risk is that the abnormal rhythm pattern may lead to electrical disturbances within the heart that can cause other problems such as double-blocked arteries, reduced blood flow to the legs, and even sudden death.
In general, individuals with LBBB have very few complications from the condition. However, if you are at high risk for cardiovascular events, doctors may recommend treatment to reduce this risk. For example, patients with LBBB who are also diagnosed with hypertension or diabetes may require medication to control these conditions.
People with LBBB may experience symptoms of heart block during exercise or emotional stress. If you are experiencing any of these symptoms, talk with your doctor about possible ways to manage them.
LBBB does not affect the overall length of your life but it can lead to serious complications if proper treatment is not administered promptly. So if you are a patient with LBBB, make sure to speak with your doctor about any future plans you have so they can give you appropriate guidance.
ROC is an abbreviation for receiver operating characteristic; LBH is an abbreviation for limb-bud and heart; and AUC is an abbreviation for area under the curve. These are all components of radiology reports.
Limb-bud and heart (LBH) refers to a radiologist's assessment of whether there is evidence of blood flow to a fetus. This information is important in determining risk to the baby. MRI can show blood flow to the fetus if it is needed. Ultrasound cannot show blood flow but it can reveal other signs of life in the fetus such as organ movement.
A radiologist reads images of the fetus to look for signs of life, such as heart activity or blood flow. If no signs of life are seen, the fetus will not survive beyond birth. However, some organs may be developed enough for transplant into an infant. A fetus that is aborted prior to cardiac activity being detected cannot be diagnosed as live or dead based on autopsy results. The only way to be sure if a fetus is alive is by measuring its heart rate with ultrasound or Doppler techniques during pregnancy.