Newly constructed spatial circumference electrocardiograph

Spatial circumference electrocardiograph which could compute the length of the spatial circumference of each vectorcardiographic loop and record the pattern of the increment of the vectorcardiographic are very easily and accurately on the bed side was constructed. CR differentiating circuits with three sets of the different time constant were used for the differentiations. Vector sum circuits applying absolute value operations reported by Imai and Nguyen Phuoc (1972) were used in this apparatus and the simplification of the consitution of the circuits and the excellent results were obtained. Examples of the spatial circumference ECG recorded in a normal subject and some pathologic conditions were demonstrated.