Why left bundle branch block is contraindication for excercise tolorance test?
Answer Raghunath, An exercise stress test us usually done to look for evidence of coronary artery disease. The EKG is monitored for abnormal changes during exercise. A left bundle branch block causes the EKG to look abnormal. This makes it impossible to tell if abnormal changes occur during exercise (since the EKG was abnormal looking at rest). Therefore, a diagnostic EKG stress test is not possible when a person has a left bundle branch block. I hope this answers your question.
