UCSF

Following publication of the original article [1], the authors identified an error in Fig. 1, in which Fig. 1A and B were reversed. The correct figure is given below. (Figure presented.) Electrocardiogram (ECG) prior to (A) and after (B) pericardiocentesis. (A) Initial presenting ECG with electrical alternans, in which the direction of electrical activity flips beat-to-beat in lead V3. (B) ECG after pericardiocentesis with resolution of electrical alternans The original article [1] has been updated.