Now you see it, now you don't: alternating bundle branch block and its clinical implications.

A case study of 24‑year‑old female is presented who suffered a sudden out‑of‑hospital cardiac arrest. Topics include examines her colleagues performed cardiopulmonary resuscitation as she was noted to be pulseless and considered the paramedics arrived several minutes later and sinus rhythm was noted on the automated external defibrillator.