Left bundle branch block (LBBB) is a cardiac conduction abnormality seen on the electrocardiogram (ECG). In this condition, activation of the left ventricle is delayed, which results in the left ventricle contracting later than the right ventricle.
The criteria to diagnose a left bundle branch block on the electrocardiogram:
It should be noted that LBBB renders the ST segment of chest leads unreliable.
The T wave should be deflected opposite the ...
more
Left bundle branch block (LBBB) is a cardiac conduction abnormality seen on the electrocardiogram (ECG). In this condition, activation of the left ventricle is delayed, which results in the left ventricle contracting later than the right ventricle.
The criteria to diagnose a left bundle branch block on the electrocardiogram:
It should be noted that LBBB renders the ST segment of chest leads unreliable.
The T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance with bundle branch block. A concordant T wave may suggest ischemia or myocardial infarction.
A mnemonic to remember the ECG changes is WiLLiaM MaRRoW, ie with LBBB there is an W in V1 and a M in V6 and with a RBBB there is a M in lead V1 and a W in lead V6
Among the causes of LBBB are:
There are also partial blocks of the left bundle branch: "left anterior fascicular block" (LAFB) and a "left posterior fascicular block" (LPFB). This refers to the...
less