"The left ventricular assist device that he has implanted allows him to be a '1b' on the transplant list and a '1a,' which is the highest priority on the list for 30 days," said Feller. "There may be other patients waiting on the list for longer periods of time at a high level on the list. Those patients would get priority."
However, some patients in Cheney's condition choose to move to a different state with shorter transplant lists to cut the wait time. Still, Feller said, there is no guarantee the right heart would become available.
"The average time on the list depends on blood type, size, priority on the wait list and area of the country where the patient is listed," she said.
Cheney said last summer that the device "will enable me to resume an active life."
Family and friends of the former vice president would not talk publicly to the New York Times with "any specificity" about Cheney's condition or what he may do down the road to confront it.
The New York Times reports that Cheney associates said he has returned to his favorite pastime of hunting and has been spending time a his home in Jackson Hole WY, where he has been spotted at the grocery store and saw the film "True Grit" in recent days.
Cheney has a long history of heart problems. He has had five heart attacks, the first in 1978 when he was just 37 years old, and the fourth in November 2000, after he and former President George W. Bush were elected to the White House.
In 2001, Cheney had a pacemaker installed into his chest, and in September 2009, he underwent elective back surgery to treat lumbar spinal stenosis.
Cheney was admitted to the George Washington Hospital on Feb. 22 2010 after experiencing chest pains. His doctors later said it was a mild heart attack -- his fifth. He was released two days later.
That hospital stay forced the former vice president to miss a breakfast with his former boss, George W. Bush, and hundreds of former White House and campaign staffers.
That event, sponsored by the Bush-Cheney Alumni Association, was to be the first time the two met in person since they left office in January 2009.
Instead, Bush dropped by to visit Cheney at his home in Virginia on Feb. 25. Cheney and Bush, both sporting dark suits, shook hands and exchanged grins on the steps of Cheney's residence in McLean, Va., before turning to wave to the ABC News camera.
"Mr. President, welcome," began Cheney.
"Lookin' good," replied Bush.
"Holding up," said Cheney.
"Lookin' good," said Bush again.
"Could be worse," the often dry-witted Cheney said.
Before his surgery and lengthy recovery period, Cheney deliberately remained in the public eye, selectively choosing interviews and appearances to deliver stinging rebukes of the Obama Administration.
In February 2010, he predicted that Obama will be a "one-term president." After the thwarted Christmas Day bomb plot, Cheney said that Obama was "trying to pretend we are not at war" with terrorists.
This was in stark contrast to former President Bush who has been largely invisible, living in Dallas and working on his presidential memoirs. The former president has given occasional speeches to business groups but has held his tongue when it comes to commenting on the Obama Administration.
The Times reports that Cheney is scheduled to fly to Texas later this month to mark the 20th anniversary of the Persian Gulf War with former President George H. W. Bush, the emir of Kuwait and other alumni of the first Bush Administration, including former National Security Adviser Brent Scowcroft and Colin L. Powell, who was chairman of the Joint Chiefs of Staff at the time.
Cheney served as Secretary of Defense under George H. W. Bush.
ABC News' Susan Donaldson James, Kim Randolph and Jon Karl contributed to this report.