Intermittent left bundle branch block revealed during anaesthesia.

Intermittent left bundle branch block is uncommon. During anaesthesia,, left bundle branch block may be related to hypertension or tachycardia and its occurrence makes the diagnosis of acute myocardial ischaemia or infarction difficult. Patients with intermittent left bundle branch block often develop established left bundle branch block, which may represent an earlier state of ischaemic heart disease. Cardiological investigation of our patient after operation did not point towards an organic cause of intermittent left bundle branch block.