Fish may provide heart care clue

Scientists will look at how the fish survives in such cold temperatures

A fish found in the waters of the Antarctic may help scientists understand how to stop human hearts beating too slowly.

The Antarctic Cod maintains a very slow heartbeat - around 10 beats per minute.

British Antarctic Society scientists hope monitoring the fish will show how it controls its heart rate in such extreme temperatures.

The work could help understanding of how to protect human hearts in bypass operations where the heart is cooled.

This study may provide interesting results for returning the heart rate to normal after it has been slowed down for surgery Dr Charmaine Griffiths, British Heart Foundation

The human heart pumps blood at between 60 and 100 beats per minute.

The researchers from the British Antarctic Survey and the University of Birmingham say their prime aim is to understand how the cod survives in the waters of the Antarctic, which can be as cold as -2°C.

Heart mechanics

The scientists will monitor the fishes' heart rates during the Antarctic winter using acoustic tags attached to the fish.

These signals picked up by underwater microphones, will be transmitted to computers in the laboratory.

It is hoped that improving understanding of how the cod succeeds in such an extreme climate will help explain what happens when a person's heart beats too slowly.

This can happen during heart-lung bypass operations, or when a person is suffering from hypothermia.

Dr Stuart Egginton, a cardiovascular physiologist at the University of Birmingham's Medical School, who is leading the study, told BBC News Online: "If you cool the human heart down by just a few degrees, it will affect the rhythm, and it will start to fail.

"If we can interpret the mechanics by which the fish hearts can operate at -2°C. we might gain some insight into what happens in the human heart."

Dr Charmaine Griffiths, spokesperson for the British Heart Foundation said: "There has been much research into new techniques to improve the safety and survival of heart operations.

"This study may provide interesting results for returning the heart rate to normal after it has been slowed down for surgery.

"We will look forward to the results of the study, though possible new methods will require large scale, clinical trials before they could be used."