bundle of His

bundle of His -'his n a slender bundle of modified cardiac muscle that passes from the atrioventricular node in the right atrium to the right and left ventricles by way of the septum and that maintains the normal sequence of the heartbeat by conducting the wave of excitation from the right atrium to the ventricles called also atrioventricular bundle, His bundle

His Wilhelm (1863-1934)

German physician. A pioneer cardiologist, His was one of the first to recognize that the heartbeat originates in nodes of modified heart muscle. In 1893 he described the atrioventricular bundle, which is now often known as the bundle of His. He is also remembered for his description of trench fever in 1916, when it was a major medical problem.

* * *

see atrioventricular bundle

* * *

a small band of atypical cardiac muscle fibers that originates in the atrioventricular node in the interatrial septum, passes through the atrioventricular junction, and then runs beneath the endocardium of the right ventricle on the membranous part of the interventricular septum. It divides at the upper end of the muscular part of the interventricular septum into right and left bundle branches which descend in the septal wall of the right and left ventricle, respectively, to be distributed to those two chambers. This bundle propagates the atrial contraction rhythm to the ventricles, and its interruption produces heart block. The term is often used to refer specifically to the trunk of the bundle (truncus fasciculi atrioventricularis) rather than the entire bundle. Called also fasciculus atrioventricularis [TA], atrioventricular b., AV b., and Kent-His b. See illustration at nodus sinuatrialis.