Abstract
In usual EKG recordings, chest leads consisted of six leads (V-1 to V-6). But in our studies 30 to 40 chest leads covering whole area of anterior thorax were recorded in order to study the P wave polarity. On the right side of anterior thorax, P waves are usually negative, and they were positive on the left side.
The borderline between the positive and the negative P wave areas situated about one inch aside along the right sternal border in healthy adults. On the borderline, P waves were biphasic in configuration. In patients with mitral stenosis, this borderline had shifted to the left side, and existed on the midsternal line. The interesting phenomenon was that this midsternal borderline of mitral stenosis moved further to the left side on physical exercises. This kind of phenomenon was never noted in patients without mitral stenosis. Authors concluded that this phenomenon was due to the increase of the left atrial pressure as well as the left atrial volume that were induced by exercises.
