EDMONTON -- Alberta Health Services is notifying about 11,500 patients that they may have been exposed to an infection during open-heart surgery.

Officials say Health Canada has reported that a device used to heat and cool blood during surgery has been linked to mycobacteria.

Alberta Health Services says it has used the device at the Foothills Medical Centre in Calgary, as well as at the Mazankowski Alberta Heart Institute and the Stollery Children's Hospital in Edmonton.

The agency says no infections have been identified so far and the risk to those who may have been exposed is extremely low.

Letters are to be mailed in the coming days to doctors and discharged cardiac patients who may have been exposed.

In October, the Winnipeg Regional Health Authority took a similar precaution and sent letters to more than 4,300 adults who have had heart surgery at the St. Boniface Hospital in the last four years.