Vectorcardiographic investigations on the auricles.

Vectorcardiography demonstrates very clearly the method of auricular activation and shows its spatial development. This is illustrated and discussed in this paper as it occurs in normal subjects, in a patient with an ectopic auricular pacemaker, and in patients with pulmonary heart disease. Changes similar to those seen in patients with cor pulmonale have been observed in dogs after partial occlusion of the pulmonary artery. Remarkable alterations of the auricular vectorcardio-gram have been seen in patients with mitral heart disease after commissurotomy. INCE THERE IS NO FINAL AGREES LMENT concerning the methods which should be used in vectorcardiography, the vectorcardiograms, registered by various investigators , are, therefore not absolutely comparable. In Vienna we use the method of Polzer and Schuhfried.' By this method the normal auricular vector loops are directed anteriorly and inferiorly. The sense of rotation is counterclockwise in the frontal and horizontal , and clockwise in the sagittal plane. Theoretically, the auricular vectorcardiogram may be subdivided into a partial vectorcardio-gram of the right and a partial vectorcardio-gram of the left auricle. The isolated vector-cardiogram of the right auricle would mainly be directed inferiorly, whereas the isolated left auricular vectorcardiogram would be directed mainly to the left, which corresponds to the main direction of activation of the left auricle. Figure 1 shows the vectorcardiogram of a normal subject. On all illustrations a potential of 1 mv. corresponds to a deflection of the vectorcardiographic loop of 2 cm.