The Vatican has acknowledged for the first time that Pope Benedict XVI has had a pacemaker for years and that its battery was replaced a few months ago in secret.
Vatican spokesman Fr Federico Lombardi said Pope Benedict had the pacemaker installed "a long time" before he became Pope in 2005.
He called the latest medical procedure "routine". It was the first time the Vatican has mentioned the pacemaker.
Italian daily Il Sole 24 said the Pope had the pacemaker procedure less than three months ago in a Rome hospital and did not miss any public appearances.
The Pope is resigning on 28 February because he said he has become too weak to handle the burdens of the papacy.
He will become the first Pope to step down since the 15th Century.
Fr Lombardi also confirmed that Benedict will step aside completely from any role in running the church after he resigns and will play no part in the election of his successor.
He said: "The Pope has said in his declaration that he will use his time for prayer and reflection and will not have any responsibility for guidance of the church or any administrative or government responsibility.
"This is absolutely clear and this is the sense of the resignation."
The Pope’s brother, Georg Ratzinger, said Benedict is planning to stay out of the public eye and will probably not write any further works during his lifetime.
Monsignor Ratzinger, who was ordained on the same day as the Pope in 1951, said his brother also has no plans to move back to Germany.
"You don't transplant an old tree," the 89-year-old said.
Pope Benedict's papacy will be remembered more for his resignation, rather than anything he may have done in office, according to Fr Peter McVerry.
Speaking on RTÉ's Morning Edition, Fr McVerry said he believed that the Catholic Church needs radical reform to get back to gospel values, and described its structures as "hopelessly outdated".
Fr McVerry said that many people are very alienated from the Catholic Church, the structures of which appeared "caught in a time warp of about 400 years ago".
He added that people see the Catholic Church as male-dominated, authoritarian and controlling.
Fr McVerry said that he was disappointed when Pope Benedict was made Pope as he had a reputation for being a traditionalist.
He feared that he would maintain the status quo and said that that is what happened during his papacy.
Fr McVerry said: "He did write a great encyclical on the global economic crisis. I think that was very radical and very good, but I don't think he'll be remembered for much except his resignation."
He said it would take a charismatic pope to deliver the changes needed.
"Can the College of Cardinals produce such a leader? It’s probably unlikely," he said.