First pig-to-human cardiac transplant alters heart's electrical signals

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 Researchers performed a 12-lead electrocardiogram (ECG) during the postoperative period of the patient who underwent the first pig-to-human heart transplantation. The ECG data were obtained every day after the xenotransplantation. The researchers reviewed the following ECG measures: PR interval, QRS complex, and QT interval. The ECG parameters of the “accepted pig heart transplant in the ‘pig body’” show short PR (50 to 10 milliseconds, ms) and QT (260 to 380 ms) intervals and short QRS (70 to 90 ms). However, the first ECG of the pig-to-human heart xenotransplant showed a relatively longer PR interval of 190 ms, QT interval of 538 ms, and QRS duration of 138 ms. Prolonged intrinsic PR intervals were stable in the postoperative period with 210 ms. There was evidence of decremental intra-atrial conduction delay on day 12 post-transplantation (PR interval: 380 ms). QRS duration was prolonged but shortened in the postoperative course. High QT intervals (509 ms) persisted with dynamic fluctuations, with the lowest (428 ms) on day 14 post-transplantation. The ECG of the pig-to-human xenograft revealed prolongation of the typical ECG measures in the donor that included changes in depolarization and repolarization. It was a novel finding that the pig heart in the human showed different ECG parameters compared to the commonly observed findings for native pig hearts. The protracted ECG parameters persisted and showed dynamic changes in the postoperative period. These are the first insights into the evolving novel field of xenografts suggesting the complex interplay of porcine denervation and inter-species physiology besides the postoperative and medication-associated changes.