Harry Whittington, 78, was recovering and will be monitored for seven days to make sure more bird shot doesn't move to other organs or move to other part of his body, hospital officials said.
"However some of the bird shot appears to have moved and lodged into part of his heart in what we would say is a minor heart attack," said Peter Banko, administrator at Christus Spohn Hospital Corpus Christi-Memorial.
Banko said there was an irregularity in the heartbeat caused by a pellet, and doctors performed a cardiac catheterization. Whittington expressed a desire to leave the hospital, but Banko said he would probably stay for another week to make sure more shot doesn't move to other organs or to other part of his body.
David Blanchard, chief of emergency care, called it "a silent heart attack, an asymptomatic heart attack. He's not had a heart attack in the traditional sense."
Doctors left the birdshot in place and said he could live a healthy life with it there.
Check out the Texas Parks and Wildlife Department's report on Cheney shooting Whittington (.pdf).
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White House physicians who attended to Whittington at the scene after Cheney accidentally shot him were involved in the treatment, the officials said.
The vice president's office said in a statement that Cheney spoke with Whittington on Tuesday afternoon and said he "stood ready to assist." The statement said Whittington's "spirits were good."
Whittington had initially been placed in intensive care after the accident Saturday evening. He had been moved to a "step-down unit" Monday after doctors decided to leave several birdshot pellets lodged in his skin rather than try to remove them.
A Texas Parks and Wildlife Department report issued Monday said Whittington was retrieving a downed bird and stepped out of the hunting line he was sharing with Cheney. "Another covey was flushed and Cheney swung on a bird and fired, striking Whittington in the face, neck and chest at approximately 30 yards," the report said.
The department found the main factor contributing to the accident was a "hunter's judgment factor." No other secondary factors were found to have played a role.
The department gave Cheney and Whittington warning citations for breaking Texas hunting law by failing to buy a $7 stamp allowing them to shoot upland game birds. A department spokesman said warnings are being issued in most cases because the stamp requirement only went into effect five months ago and many hunters weren't aware of it.