Electrocardiographic and epicardial mapping studies are reported in a child with an atrial septal defect and a variant of type A Wolff-Parkinson-White (WPW) syndrome. The vectorcardiogram suggested a posterior area of early activation and this was confirmed by epicardial mapping studies. Premature activation apparently occurred from a site near the endocardium of the basal region of the left ve...

The noninvasive localization of the accessory pa thway (AP) responsible for ventricular preexcitation is helpful in the initial evaluation of patients with Wolff-Parkinson-White (WPW) syndrome. Recently, two groups of authors independently published new classifications derived from the correlation of 12-lead ECG with electrophysiologic studies. ~'2 Although these classifications allow a more pr...

IN recent years there has been increasing interest in the clinical application of spatial vectorcardiography. Some comparative studies have indicated that the vectorcardiogram may be significantly superior to the conventional scalar electrocardiogram in the diagnosis of myocardial infarction and ventricular hypertrophy." 2 The Frank lead system3 has many theoretical advantages over the older ve...

From the means and standard deviations of the coordinates of the spatial QRS and T vectors in 178 normal middle-aged men, preliminary normal range limits were calculated for the total group, three positional subgroups, and three relative body weight groups. The superiority of spatial vector analysis over analysis of the scalar electrocardiogram made it possible for the first time to investigate...

Studies were done on dogs in vivo to determine the effect of intracardiac blood on the electrocardiogram. By exchange transfusions of packed cells or of Rheomacrodex, hematocrit was raised to over 70% or lowered to 16%. The electrical resistivity of the blood changed accordingly from control values of 150 ohm-cm to over 500 ohm-cm or to as low as 67 ohm-cm. The x-, y-, and zvector leads were pr...

A method of vectorcardiography, in which the projections of the spatial veetorcardiogrami in various planes of an equilateral tetrahedron reference system are recorded, has been applied to the study of left bundle branch block. Results suggest that the method employed may provide information relative to the state of the miyocar(liutim and the extent of myocardial lesions which is not evident fr...