[Left atrial rhythm. Electrocardiographic study (author's transl)].

The electrocardiograms of 15 left atrial rhythm and sinusal rhythm patients are studied. The spontaneous occurrence of LAR and the possibility of return to SR by vagal stimulation manoeuvers are reported. The electrocardiographic modifications of the ectopic rhythm are shown and compared either with those of the coronary sinus rhythm or junctional A-V rhythm, or with those of the tracings recorded during atrial pacing. The intermittent occurrence of the LAR in the studied cases is theoretically ascribed to the awakening of an ectopic focus, localized in the left atrium, acting as a new pace-maker because of its excited activity or abnormal depression of the sinus.