Abstract
Evidence has already been presented 1 to show that interruption of the blood supply to a given ventricular muscle band will produce a characteristic and constant alteration in the electrocardiogram.
The present report is concerned with consecutive electrocardiograms from a single dog in which the coronary blood supply to muscle after muscle was obstructed. The technique was as previously described, allowing half hour intervals between successive ligatures. Ligatures were placed near the apex on the vessels supplying: the internal portions of the Superficial Sino- and Bulbo-spiral muscles, the deep Sino-spiral (both right and left portions), the deep Bulbo-spiral, the Septum (4 ties 1 cm. apart from below upwards on the anterior descending coronary) and one on the branch from the left circumflex coronary to the upper posterior septum. Finally, the whole left circumflex branch of the left coronary was ligated. At this time the only adequate blood supply was to a small area on the anterior surface of the right ventricle, to the right portion of the scroll muscles and to the bundle of His.
As soon as a vessel is ligated the area involved ceases to contract, assumes a dusky color and bulges slightly. The electrocardiogram indicated that when the ligations were made serially in one animal, each characteristic modification reported previously was again introduced as a typical addition to or a subtraction from the previous tracing.
The amplitude of the records became progressively greater as the lesions progressed. When only this small area of the right ventricle could be seen to beat there was a high R in Lead I. This experiment was later repeated with similar results.
Get full access to this article
View all access options for this article.