Abstract
The present paper is concerned with qualitative and quantitative analysis of changes in vectorcardiogram (VCG) characteristic of the systolic and diastolic overloading of the left ventricle, which may, be more markedly manifested in essential hypertension and aortic regurgitation respectively. The results obtained are as follows : Materials and Methods 120 patients with essential hypertension (EH group) and 24 patients with aortic regurgitation (AI group), and 73 normal adults (control group) were subjected to this investigation. Spatial VCG with the Frank system in three planar projections were simultaneously photo-graphed, and three scalar ECG as well as conventional ECG of 12 leads were also coincidentally recorded. For precise analysis of the time factor, vector loops enlarged 15 times through a photographic projector were traced on a paper. Based upon these documents, X, Y and Z components in each instantaneous QRS vector, spatial maximum QRS and T vector were measured. The variables thus obtained were analyticogeometrically analyzed by means of the digital computer "OKITAC 5090 H", managed at the Computation Center of Kyushu University. Results and Discussions 2. 1. Directions of the initlal and terminal QRS vector (Table I). As shown in Table I, the initial QRS vector are frequently directed anterosuperiorly to the right, comprising 60 per cent of the EH and 58 per cent of the AI group. Only one case among the AI group showed the left and posterosuperior direction. The terminal QRS vector is mostly directed to the right posteriorly in the control group (85%). The left and posterosuperior direction in the terminal QRS vector was seen in 13.3 per cent of the control group, whereas in 26.6 and 50 per cent of the EH and AI groups respectively. 2. 2. Rotating directions (Table II). Counterclockwise rotation (CCW) of the frontal QRS loop was observed in 21.7 per cnt of the EH, showing a tendency similar to the control group (20.5%). On the other hand, the incidence of clockwise rotation (CW) was significantly smaller among the EH group (8.3%). CCW rotation of the frontal QRS loop was observed in 66.7 per cnt of the AI group. CW rotation of the horizontal QRS loop was observed in 16.7 per cnt of the AI group, while any sign of CW rotation is not observable in the EH and control groups. CW rotation of the horizontal and sagittal T loop was observed in 80 per cnt of the EH and AI groups.
