Harry Whittington was 30 yards away from the vice president when he was accidentally shot on a Texas ranch on Saturday, but the birdshot has penetrated deeper than anyone had expected. After suffering a heart attack as a direct result of the shooting, Whittington spent Tuesday night in the intensive care unit.
"It is one problematic birdshot in this particular case that we feel has caused the entire problem," said Dr. David Blanchard of Christus Spohn Hospital Corpus Christi-Memorial in Corpus Christi, Texas.
Doctors believe that a 5-millimeter birdshot is lodged in his heart muscle.
"The birdshot was not ever in the chamber of the heart," said Peter Banko, the hospital's administrator.
Doctors performed a cardiac catheterization on Whittington, 78, inserting a thin probe through an artery into the heart. They found his arteries to be clear.
"If he had bad arteries, he would be at much greater risk," said ABC News medical contributor Dr. Tim Johnson. "His good health also means there's less strain on his heart in general, despite his advanced age."
Whittington's heart attack was not "a traditional heart attack," but rather a result of a "direct traumatic injury to the muscle," Johnson said.
The doctors say a high-tech, 3-D heart scanner won't pinpoint the birdshot because it is metal and will blur the image.
"If they have the machine, which they say they do, why not try it?" Johnson said."It's a benign test, very quick."
The plan for now is to let the birdshot stay in Whittington's heart muscle.
"At this point in time there is no plan to do surgery to remove the birdshot," Banko said. "It is fixed in the heart at this point in time."
Johnson said that if the birdshot was lodged in the heart muscle, it was unlikely that it would migrate into the heart. Whittington, however, could be at risk for lead poisoning from the shots, although Johnson said that was unlikely, too.
"It depends on the amount of birdshot he has in his body," Johnson said. "We have been told the count could be as low as six and as high as 200. That's a big range, and the more birdshot, the greater the chance of lead poisoning."