The Corrected QT Interval Before and After Heart Transplantation

Abstract

Heart donor candidates have severe neurologic injuries that have been associated with significant prolongation of the corrected QT (QTc) interval. Screening for an underlying abnormality of cardiac repolarization such as the long-QT syndrome thus becomes difficult. The aims of this study were to establish normal values and determine factors associated with prolongation of pre- and post-transplantation QTc intervals in a large cohort of heart transplantation donors and recipients. The medical records of 179 donors and 112 recipients were reviewed for historical, electrocardiographic, and neuroimaging data. After linear regression analysis, gunshot wounds were associated with the shortest mean pre-transplantation QTc interval of 447 +/- 51 ms (p = 0.016), whereas all other mechanisms of brain injury were associated with markedly prolonged QTc intervals. Overall, the mean QTc interval decreased from 467 +/- 58 to 446 +/- 47 ms (p <0.001), the mean QRS duration increased from 87 +/- 16 to 98 +/- 21 ms (p <0.001), and the mean QT dispersion did not change significantly after transplantation. The only factor associated with a prolonged QTc interval in the post-transplantation period was hypokalemia, with a mean QTc of 468 +/- 37 ms (p = 0.047). In conclusion, the mechanism of donor brain injury is associated with alterations in the pre-transplantation QTc interval, with the shortest intervals related to gunshot wounds. Fewer than 5% of the donor population was found to have QTc interval > or =580 ms. For those afflicted by gunshot wounds, <5% had QTc intervals > or =550 ms. This information can be used in pre-transplantation donor assessment, and post-transplantation management can be tailored to avoid the occurrence of ventricular arrhythmia.