On the R-T interval in experimental coronary occlusion.

Abstract

In 1918 Smith 1 published electrocardiographic tracings following ligation of coronary vessels in the dog. In one tracing, five minutes after tying the circumflex branch of the left coronary artery, there occurred, among other changes, marked elevation of the T-wave, with the T-wave originating on the down stroke of the R-wave, when the latter had reached about one-half the distance to the base line.

In 1920 Pardee 2 published a similar electrocardiogram obtained from a patient four hours after an obstruction of a coronary vessel.

More recently, Rothschild, Mann, and Oppenheimer 3 renewed the interest in the peculiar change of the R-T interval as an early diagnostic sign of coronary obstruction. They reported observations on four patients shortly after acute coronary occlusions in which among the first changes in the electrocardiogram there was the characteristic elevation of the R-T interval above the base line.

In 1909 Eppinger and Rothberger 4 observed in dogs that partial or complete absence of the desecending limb of the R-wave was a relatively frequent and characteristic occurrence following the injection of silver nitrate solution into tlie muscle of the left ventricle whether at the base or apex. The T-wave became high and broad and originated either at the peak of the ascending limb of the R-wave or from the lower end of the descending limb which failed to reach the base line. They explained this effect on the basis of impaired contraction of the mass of circular muscle fibres in the structure of the left ventricle.