ECG Results in First Ever Genetically Modified Pig Heart-in-Human Body Transplantation

The first ever genetically modified porcine-to-human cardiac xenotransplant (pig heart-in-human body) shows electrocardiography (ECG) parameters with prolongation over the typically encountered ECG measurements in the donor (pig heart-in-pig body) that include changes in cardiac repolarization and depolarization. The ECG prolonged parameters persist with significant changes in the post-operative period. These findings were presented at the American Heart Association (AHA) Scientific Sessions 2022, held from November 5th through 7th, in Chicago, Illinois.

Researchers sought to evaluate the first genetically modified porcine-to-human cardiac xenotransplantation to take place worldwide.

In January 2022, at the University of Maryland, a recipient received the first ever genetically modified porcine-to-human cardiac xenotransplantation. The researchers collected daily 12-lead ECGs during the post-operative period, and the recipient survived for 61 days.

“Pig heart-in-pig body” accepted parameters included a short pulse rate (PR) interval (50-120 milliseconds [ms]), short QRS duration (70-90 ms), and short QT interval for repolarization (260-380 ms). In the genetically modified heart xenotransplant (“pig heart-in-human body”) the first ever ECG showed a longer PR interval (190 ms), QRS duration (138 ms), and QT interval (538 ms) in the setting of sinus bradycardia, interventricular conduction dela,y and inferior/antero-lateral T wave inversions.

The researchers noted that during the post-operative period, the prolonged PR intervals remained stable (210±22 ms; range, 142-246 ms). Decremental intra-atrial conduction delay/AV-conduction delay was observed in atrial pacing, most pronounced on day 12 (PR, 380ms).

They found that, during the post-operative course, the QRS duration had remained prolonged with 145±16 ms (range, 116-192 ms) shortened (day 21-40 [148±14 ms] vs day 41-60 [132±11 ms]; P <.001). They noted the persistence of the increased QT 509±54 ms (range, 384-650 ms) with dynamic fluctuations (QT low-point) around day 14 (428±22 ms vs 533±36 ms; P <.001). 

“ECG parameters of the first genetically modified porcine-to-human cardiac xenotransplant (‘pig heart-in-human body’) demonstrated prolongation over the usually encountered ECG measurements in the donor (‘pig heart-in-pig body’) including changes in cardiac depolarization and repolarization,” the researchers wrote.  “Prolonged ECG parameters persisted but showed dynamic changes during post-operative period.” Their results suggest a multifaceted relationship between porcine denervation and interspecies physiology.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.