Left Bundle Branch Block

Left bundle branch block refers to a conduction block in any part of the left-sided conduction pathway from the bundle of His to the fascicles which slows the depolarization and contraction of the left ventricle ( Assessment of an incidental finding of the left bundle branch block David Warriner et al April 2005 )

Activation of the left ventricle is delayed with respect to the interventricular septum - leading to an inefficient pumping action In the normal direction of of septal depolarization is reversed from left to right to right to left LBBB completely modifies the the electrical activation of the left ventricle and the QRS complex on ECG The consequence is impairment of systolic and diastolic left ventricular function

How common - First described more than 100 yrs ago LBBB is a rare finding in young people and almost never happens before age 35 Estimated prevalence is between 0.1 % to 0.8 % Approximately 33 % of patients with heart failure have LBBB It increases with age - from < 1 % before age 50 to 6 % by 80 yrs Incidental LBBB occurs in up to 1.5 % of healthy people without symptoms or signs of CV disease...