Hi guys

Today I wanted to do a video on left bundle branch block. Several of you have seen my video on RBBB and then written to me and said can you do one on LBBB So here goes: The first thing to say is that the Left bundle branch block refers to abnormal electrics and not abnormal plumbing.

A lot of people hear the word block and assume that they have heart artery blockages and this is an incorrect assumption. LBBB is an electric issue not a heart artery issue.  Secondly left bundle branch block is a pattern on an ECG.

You do not go to your doctor and say I have LBBB and neither can a doctor examine you and say you have LBBB. The only time LBBB is diagnosed is when it is seen on an ECG.

Let me talk you through the electrics of the heart.

In the normal person, electricity is generated in a part of the heart called the pacemaker or the sinoatrial node. The electrical impulse then travels down some wiring and the wiring separates into a left bundle which supplies electricity to the left heart and a right bundle which supplies the right heart, if there is a problem with the wiring supplying the left heart then it is called LBBB. If there is a problem with the wiring supplying the right heart then it is called RBBB.

Usually, both sides of the heart receive the electricity at the same time but if you have left bundle branch block then the right ventricle will contract first. Because all muscle is capable of transmitting electricity, the left heart will still receive electricity but it will come through the right bundle and therefore the left heart will contract later than the right heart.

Left bundle branch is always abnormal and therefore should always prompt investigation.

Note I said abnormal and not dangerous and infant if you have had the investigations and nothing found then it does not really signify any risk to you in the long term. Left bundle branch block can occur with advanced age but more often if there is underlying heart disease such as a damaged heart, an excessively thick heart, infections of the heart such as lames disease and myocarditis and also high blood pressure.