Abstract
In order to find the three-dimensional distribution of ventricular depolarization potentials in left anterior hemiblock (LAHB) diagnosed by the conventional scalar ECG, 7 subjects with LAHB aged 9 to 62 years old who were otherwise healthy were studied by computer graphic electrocardiography (CGECG).
Two modes of the initial ventricular depolarization (IVD) were noted. (1) The IVD appeared irregularly and separately on the mid- to lower central region of the anterior body surface. (2) The IVD appeared in a form rather like a parallelogram on the central region of the anterior body surface. Both (1) and (2) potentials propagated toward the left middle, lower, and lateral regions of the anterior body surface as normally observed; however, they were far lower in voltage than those observed in intact subjects.
From the results, it has been concluded that LAHB may be, not a block, but rather a defective ventricular septal conduction.
