[Classification and clinical-electrocardiographic evaluation of his bundle-branch block]

Investigation covered 114 patients with ischemic heart disease exhibiting electrocardiographic signs of deranged intraventricular conduction. Major ECG changes with blocked left anterior and left posterior brances of the bundle of His and also in combined blocks of two and three branches are described. A quantitative spatial analysis of the ECG in corrected orthogonal leads after McFee with determination of the initial, terminal and median orientation of the QRS vector in the frontal plane, as well as of the azimuth and elevation was made. A classification of the His bundle-branch block is proposed. It includes single-, double- and triple-bundle branch blocks. Clinical and electrocardiographic comparisons showed that disrupted conduction in the ramification system of the bundle of His occurs with marked diffuse or focal alterations in the myocardium of the left ventricle observed in patients afflicted with different forms of ischemic heart disease.