Recently Hamburger, Katz and Saphir1described two cases of electrical alternans without pulsus alternans —the first reported in this country. This electrocardiographic phenomenon (fig. 1) has been exceedingly rare, but now that the Chicago investigators have made cardiologists "alternans conscious," to use their expression, we believe that relatively many more cases will be reported. The two cases that are the subject of this report include one case of electrical alternans with demonstrable pulsus alternans and one case in which pulsus alternans was not demonstrated. Our first case was discovered Jan. 22, 1935. Careful search through our files then brought the additional case to light. Electrical alternans consists of a regular alternation at equal intervals, in contour or amplitude, or both, of successive phases of the electrocardiographic record. White2says that electrical alternans accompanying pulsus alternans is rare; the QRS or T waves may rarely alternate in amplitude although