[Studies on the spatial velocity electrocardiogram in left ventricular overloadings].

Conventional ECG, Frank system VCG and the spatial velocity ECG were recorded in 42 cases of healthy adult men, 76 cases of hypertension and 26 cases of aortic insufficiency, and were studied qualitatively as well as quantitatively in order to clarify the characteristic changes in the spatial velocity ECG in the systolic and the diastolic overloadings of the left ventricle. Spatial velocity ECG were recorded by means of the spatial velocity electrocardiograph, leading three scalar ECG of Frank system (X, Y, and Z leads) into the differentiating, the squaring, the adding and the square root circuits in orders. Computations were performed automatically according to the following formula: see journal for formula. Spatial velocity ECG and three scalar ECG of Frank system were simultaneously recorded by the four channel heatwriting oscillograph with paper speed of 100 mm per second. The forty Hz and 4 Hz of the sinusoidal waves were introduced into the circuits for the calibrations of QRS and P and T waves respectively. P waves of the spatial velocity ECG in normal subjects showed 2-peaked (5%), 3-peaked (6%), and 4-peaked (26%) patterns exhibiting 3-peaked P waves as the basic pattern in normal. The three peaked and 4-peaked patterns were observed in 33% and 67% in hypertension, and in 35% and 65% in aortic insufficiency respectively. Two-peaked P wave was not observed and the incidence of the 4-peaked P waves of the spatial velocity ECG increased in the left ventricular overloadings..