The first successful transplant of a genetically engineered pig heart into a person was performed in January of this year. David Bennett, the patient, made it through 2 months with the pig heart, and the groundbreaking operation that resulted in the transplant sparked a number of fascinating discoveries and avenues for further study.
One study that was just released shows that the electrical conduction system of the heart of a genetically modified pig is different from that of a normal pig. The results are in accordance with electrocardiogram (ECG) data taken from the pig heart that was transplanted into David Bennett.
Once the transplant was complete, a 12-lead electrocardiogram (ECG) was used to check in on the pig heart’s electrical circuitry. After one day had passed since the xenotransplant procedure, the researchers examined the ECG data. The QT interval, the PR interval, and the QRS complex were all looked at.
The former represents how long it takes for an electrical impulse to move from the heart’s lower chamber to finish a full cycle. When the heart generates electricity, it flows from the upper to the lower chamber, which corresponds to the PR and QRS waves that indicate the passage of time. During a heartbeat, both of these values are related to the flow of electricity through the heart.
The original hypothesis for the xenotransplant was that it would function similarly to a pig heart. Some anatomical variations between the pig heart and the human heart allow for rapid conduction of electricity from the upper to the lower chamber. Because of this, the pig heart can complete an entire pulse cycle considerably quicker than the human heart can.
Within the pig’s body, a normal PR, QRS, and QT intervals are 50-120 ms, 70-90 ms, and 260-380 ms, correspondingly. Comparatively, the PR, QRS, and QT timings for the genetically engineered pig heart inside the patient’s body were 190 ms, 138 ms, and 538 ms. Later ECG recordings also showed longer PR and QRS intervals for a while, as noted by the investigators.
