A revolutionary pig heart transplant for humans has worked better than doctors had hoped

We all remember the big news earlier this year when a 57-year-old heart patient was given a new lease of life thanks to a genetically modified pig heart. It was a revolutionary operation that extended a man’s life and marked the first time that a pig heart has ever been xenotransplanted. Although the man died after two months (probably due to swine virus), it turns out that the heart beats more like a human heart than doctors expected, new research reveals.

Preliminary research to be presented at Scientific Lectures of the American Heart Association showed that compared to pig-to-pig heart transplants, xenotransplanted pig hearts beat more slowly than expected. In fact, the electrical signals of the new human heartbeat more closely resembled those of the human heart, and even surpassed those signals in several metrics.

“It is a truly novel discovery” that electrocardiogram (ECG) measurements, which record the heart’s electrical signal, are so different from typical pig heart readings,” Team Dickfeld, an electrophysiologist at the University of Maryland School of Medicine who led the research, said in a press release. Those measurements, he added, “extended to what we see in the human heart, and often the measurements even exceeded what we consider normal in the human heart.”

After the man’s surgery, doctors took daily EKG readings from the genetically modified pig’s heart, finding that two key components of the signal remained longer than usual after the transplant. In humans, Dickfeld said, prolonged times for these measurements can indicate electrical or heart disease. Future research will want to examine how EKG measurements can inform doctors about a patient’s risk of organ rejection or other negative outcomes.

Although the idea of ​​transplanting a heart from a pig to a human circulated in the popular imagination only three such procedures have occurred in decades. After David Bennett Sr.’s surgery in January, researchers at NYU Langone Health transplanted pig hearts into two brain-dead people and studied the organs for 72 hours. All three pig hearts were genetically modified to suppress their growth when placed in the smaller human chest cavity and to reduce the likelihood of organ rejection. With hundreds of thousands of Americans waiting for organ transplants amid a donor shortage, doctors hope that xenotransplants could one day make up the difference and save lives.