[Compensation of the effects of shifts of anatomic positions of the heart on electrical tracings].

The heart can take different anatomical orientations in the chest of various subjects and even in the same subject. The corresponding changes in perspective can deeply affect the electrical tracings recorded by fixed standardized leads. One same electrogenesis takes many appearances, complicating the analysis. Anatomically intrinsic tracings can be obtained with O. H. Schmitt's Resolver from a usual X, Y, Z lead system. Its moving trihaedral X'', Y'', Z'', has to be brought onto the heart's axis and septum. Being directly related to the heart, these tracings become independent of the heart's anatomical position in the chest. They show the electrical to anatomical topographic relations. However, they have not been in favour because Clinicians could not relate them to their usual rules of interpretation. This Note describes how to obtain normalized tracings that can benefit from the usual criteria of interpretation, as if shifted hearts were seen in an intermediate position. A constant opposite intermediate shift is applied to the three, X'', Y'', Z'', intrinsic components to restore an arbitrary normalized position. The new X'', Y'', Z'', components follow the moving trihaedral brought on the individual anatomical position measured by X rays and echocardiography. A heart being naturally in an intermediate position gives tracings as if no Resolver was in action. Compensated (or normalized) ECG's or isopotential maps can be similarly computed.