Nature of the conduction disturbance in selective coronary arteriography and left heart catheterization

The electrocardiographic changes associated with coronary arteriography were compared with those occurring during left ventricular catheterization in 16 patients. In 1 patient, a 36 year old man, transient left anterior divisional block was documented when the catheter tip was in the outflow tract of the left ventricle. The ÂQRS shifted from +90 to −50°, the initial 0.02 second QRS forces shifted interiorly and to the right, and the QRS interval increased from 0.07 to 0.09 second, fulfilling previously described criteria for the diagnosis of left anterior divisional block. This was attributed to transient injury of the anterior division of the left bundle branch. During recovery, several progressively decreasing degrees of left anterior divisional block were recorded.