Symptoms of a Left Bundle Branch Block

People are not often thought of as electrical devices, yet our hearts produce electrical patterns that give doctors insights into our cardiovascular health. One example is a condition known as "bundle branch block." Imagine the heart's electrical output traveling on a road. Now imagine the electricity hitting a pothole. Bundle branch block is like that pothole. Just as a pothole is an indicator that the road may need repair, a branch block is a sign of a more serious problem.

Left Versus Right

Bundle branch block comes in two varieties, based on the location of the signal blockage. Left bundle branch block is considered more serious than right bundle branch block, and there's also a greater likelihood that someone with left bundle branch block will experience symptoms. However, people with left bundle branch block may exhibit few to no symptoms. Often the presence of perceptible symptoms indicates a more serious heart condition.

Vague Symptoms

Left bundle branch block is characterized by a couple of vague symptoms that could result from many conditions, including anxiety. One such symptom is dizziness, and the other is the fainting sensation of presyncope. While many other conditions can have the same symptoms, chronic bouts of dizziness and lightheadedness warrant a doctor's visit.

Acute Symptoms

People with left bundle branch block may suffer from a slower heart rate (brachycardia). In addition, bouts of fainting are common.


An electrocardiogram (EKG) gives your doctor a readout of your heart's electrical output. From that readout, certain patterns emerge. Bundle branch blocks appear as variations from the normal EKG wavelength pattern. Based on where the variations occur, a trained doctor can distinguish the location of the bundle branch block, left or right.


On its own, left bundle branch block doesn't require any treatment. However, since its presence is an indicator of a more serious condition, you'll need treatment based on that condition. Special pacemakers are installed if someone requiring a pacemaker also shows signs of bundle branch block. If the branch block is associated with blood pressure complications, you may need to take blood pressure medicine. Overall, left bundle branch block should be treated as a warning. Make sure your cardiologist gives you a thorough examination and determines what condition is causing your bundle branch block.