Second look diagnosis: dual sinus nodes rhythm in heart transplant patient

A 76‐year‐old woman presented to our regional hospital with coronavirus disease 2019 (COVID‐19)‐related symptoms. Her past medical history was significant for an orthotopic heart transplant in 2007 (no records available). An electrocardiogram showed sinus rhythm 65 beats per minute, but we noted increased atrial activity with two distinct p waves on the rhythm strip (Figure, A and B): the preserved recipient and the donor sinoatrial node activity, which is typical for biatrial heart transplants.1,2 Only the transplanted sinoatrial nodal activity is able to conduct to the ventricles, as the surgical anastomosis creates an electrical block that prevents transmission to the ventricles (Figure, B).