Left Bundle-Branch Block

Source:http://linkedlifedata.com/resource/umls/id/C0023211

NCI: A cardiac rhythm characterized by QRS duration 120 ms or longer, delayed onset of intrinsicoid deflection in 1, V5, and V6 >60 ms, broad and notched or slurred R waves in I, aVL, V5, and V6, rS or QS complexes in right precordial leads, ST-segment and T waves in opposite polarity to the major QRS deflection.,NCI: An impairment of transmission of the cardiac electrical impulse along the fibers of the left main bundle branch, or both the left anterior fascicle and left posterior fascicle. This conduction disturbance is characterized by wide (greater than 0.11s) QRS complexes. The diagnostic criteria consist of prolongation of the QRS complexes (over 0.11s) with neither a Q wave nor an S wave in lead V1 and in the properly placed V6. A wide R wave with a notch on its top (plateau) is seen in these leads. In hearts with an electrical (and anatomic) vertical position a small Q wave may be seen in AVL in the absence of MI. Right chest lead V1 may or may not show an initial R wave, but the latter should be pres

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