A left anterior fascicular block is an interruption of the electrical impulse in one of the pathways that carries electrical signals through the heart.
To determine whether the block is serious, it is important to check for any underlying heart conditions and evaluate how well the heart is functioning. Ideally, this should be done by a cardiologist or by the healthcare provider who ordered the test.
A left anterior fascicular block may not cause significant problems when it occurs on its own. However, if there are other existing heart abnormalities, this type of block can increase the risk of cardiovascular complications.