There are three grades of AV block, with increasing severity of the block: First-degree AV block ... not predictable and can occur randomly. Bundle branch blocks occur when there is a problem ...

A trifascicular block is the combination of a right bundle branch block, left anterior or posterior fascicular block and a first-degree AV block (prolonged PR interval). The term “trifascicular ...

First degree heart block is typically asymptomatic. It generally does not cause problems or require treatment. Second degree heart block can come with a slower and sometimes irregular heart rhythm.