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.