One of the highest-ranking Vatican officials is being compelled to testify this weekend in a public hearing about clerical sex abuse in an unusual demonstration of holding even the most senior Catholic bishops accountable for the scandal.

Cardinal George Pell, Pope Francis' top financial adviser, will testify in a Rome hotel conference room for three nights running, answering questions via video link from Australia's Royal Commission with his accusers on hand to confront him.

The arrangements, including the 10 p.m.-2 a.m. testimony window to suit Australian time zones, were made after Pell asked to be excused from traveling home to testify in person because of previously undisclosed heart conditions — a heart attack, heart disease and hypertension — that made flying too risky.