Southwest flight turned around after human heart left on board

In a statement, Southwest described the organ on flight 3606 as "a life-critical cargo shipment". Photo / Getty Images

Passengers on a flight from Seattle to Dallas were turned around for an unusual reason over the weekend – a human heart was left on board.

While the heart should have been taken out of the cargo hold in Seattle, it was mistakenly left on the Southwest Airlines connecting flight, USA Today reported.

During the flight on Sunday (local time), passengers were informed by the captain why the flight had to redirect, explaining that the heart had been left on board after a previous flight from Sacramento, California.

A screenshot from FlightAware shows the return of the Dallas-bound flight to Seattle. Photo / FlightAware

Dr. Andrew Gottschalk, who was on the flight, told the Seattle Times that while passengers were shocked by the news, everyone on board "was happy to save a life".

Others became concerned after reading that hearts were only viable for transplant for a few hours.

In a statement to USA Today, Southwest referred to the organ on flight 3606 as "a life-critical cargo shipment" that was "intended to stay in Seattle for delivery to a local hospital."

The Seattle Times reported that no hospitals in the area said they were involved. Spokeswomen for regional organ-procurement organisations in Washington and California also said they would never use commercial flights for heart transplants.

It was later revealed that the heart was being sent to a tissue processor to recover a valve for transplant.

Passengers on board the Southwest Airlines flight were "happy to save a life". Photo / Getty Images

Deanna Santa of Sierra Donor Services in Sacramento told the Seattle Times that there was no designated patient for the valve.

"The most important part is that no one was waiting," she said.

The heart was not affected by the delay in transportation.