DENVER An American physician evacuated last week from Antarctica because of a gall bladder attack underwent heart surgery on Thursday after it was discovered that he had also suffered a mild heart attack, officials at the Swedish Medical Center here said.

According to Reuters, Ronald Shemenski, the lone doctor in a 50-person research center, was diagnosed last month with gall stones and pancreatitis and evacuated from the Amundsen-Scott South Pole station in a daring air rescue amid temperatures of about minus 60 Fahrenheit (minus 51 Celsius) and gusting winds.

Shemenski, 59, was scheduled to have his gall bladder removed Thursday morning, but after preoperative tests showed two blocked arteries his physicians canceled that operation and instead performed angioplasty.

Results from an EKG, which is a standard preoperative test, showed that Shemenski suffered a mild attack while he was in Antarctica, officials said .

He told his physicians that he suffered mild chest pain and a fever in December and the doctors speculate that was when he suffered the heart attack, hospital spokeswoman Ramonna Tooley said.

Shemenski arrived in Denver on Sunday and was eager to get his medical treatment underway so he could return to the South Pole. But instead he will recuperate from the cardiac procedure at home in Ohio and probably return later to Denver for the gall bladder surgery.

During the angioplasty, coronary stents were implanted in the two arteries that were blocked. A coronary stent implant is a small, slotted, stainless steel tube that helps hold the artery open and improve blood flow.

Shemenski, who had never been diagnosed with heart trouble, was resting comfortably and expected to leave the hospital on Saturday, the hospital said.

Shemenski was treated in Denver because the company that operates the South Pole station under a contract with the National Science Foundation, Raytheon Polarservices, is in Colorado.