Transient Auriculoventricular Dissociation With Varying Ventricular Complexes Caused by Digitalis

In 1913, Cohn1 and Oppenheimer and Williams2 described cases of heart-block in which the form of the ventricular complex showed fre- quent change.In Cohn's case the heart-block was transient.On Aug. 22, 1910, the patient showed partial heart-block with a 3-2 rhythm as shown by polygraphic tracings.On Feb. 10, 1911, this patient was studied again and showed a partial heart-block with a 2-1 rhythm.On February 11 and 13 there was a complete auriculoventricular dissociation.At this time electrocardiographic tracings were made and it was found that successive ventricular complexes changed their outline so that no two were precisely alike.Two general types, however, could be distin- guished, the one resembling the type of beat arising from stimuli originating in the wall of the right ventricle and the other those arising in the wall of the left ventricle.Gradual variations were made out between these two types.With the change in type there was also a change in interval between successive ventricular complexes.This dissociation did not persist, for shortly after this time the rhythm was restored to a normal one.Later examinations on Dec. 19, 1911, and Feb. 18, 1913, showed that the normal rhythm had been maintained except for an occasional premature ventricular contraction.This was a patient with cardiac decompensation, the etiology of which is not clear from the history.It appears to have been a slowly developing myocardial insufficiency.It seems not unlikely that the heart-block observed at the various times was the result of digitalis therapy.In the case of Oppenheimer and Williams the heart-block was per¬ manent during the period of observation from Feb. 26, 1912, to the day of the patient's death, Dec. 31, 1912.Histologie examination of the heart, however, revealed no organic lesion to account for the