Is bundle branch block a serious condition?

Yes: Bundle branch block is a significant abnormality that is typically discovered on an abnormal ECG (electrocardiogram) and should be further evaluated by a cardiologist.

Bundle branch block: There are two types right bundle and left bundle branch block. Right bundle is most often benign or due to right ventricular hypertrophy. Left bundle is often caused by hypertension and left ventricular hypertrophy. Acute left bundle branch block can be very serious. Generally your physician can determine whether the bundle branch block has pathophysiologic significance.