Walesa's health has been a matter of concern for some time and in 2007 he said he was in line for a heart transplant, the news.pl reported Thursday. Doctors in the United States implanted a pacemaker in the former Solidarity leader in 2008.
Walesa's heart problems mean any infection is a potential threat to his life, the report said. He was hospitalized Wednesday.
"Doctors are trying to eliminate the temperature, and make a diagnosis," said Jerzy Borowczak, a member of Parliament and a close friend of the 67-year-old former labor leader and president. "Everything is alright with his heart."