title: Circadian rhythms in human heart homograft.
abstract: The electrocardiogram and cardiotachogram of a patient with a human heart transplant has been recorded for 72 hours. Within the donor P-QRS-T complex, one can identify the P waves emanating from residual sinoatrial heart tissue of the recipient. The recipient P waves are independent of the donor complexes. A clear circadian rhythm (23.4 hours) in heart rate is maintained for both donor and recipient tissue, the donor complexes preceding by a phase shift of 135 minutes the complexes of the recipient heart tissue. Both tissues display clear morning and evening minimum and maximum rates paralleling activity and lighting cycles.
mesh_terms: D002940:Circadian Rhythm; D004562:Electrocardiography; D004568:Electrodiagnosis; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D012849:Sinoatrial Node / Q000502:physiology; D014184:Transplantation, Homologous