Gross irregularity of the pulse signifies, as a rule, that fibrillation of the auricles is present with the resultant ventricular arrhythmia. Rarely a gross sinus arrhythmia not dependent on respiration or an auricular flutter with irregular grades of heart-block may produce a condition of the pulse simulating that of auricular fibrillation.
In the case here described, an unusual cause of the gross arrhythmia was found, consisting of a curious aggregation of ectopic contractions arising from at least three different points in the ventricles, with now and then an aberrant beat of supraventricular origin slipping in (Figs. 1 and 2). The time intervals between the ventricular complexes are shown below the electrocardiogram. On several occasions while the patient was under observation at the Massachusetts General Hospital this arrhythmia was found. At other times there occurred a bigeminy due to ventricular premature beats alternating with the beats of supraventricular origin (Fig. 3).