The leader of ultranationalist Popular Orthodox Rally (LAOS), Giorgos Karatzaferis, is being treated in an intensive care unit at an Athens hospital after undergoing surgery.
Karatzaferis was admitted to a private hospital in Maroussi, northern Athens, on Saturday afternoon after feeling unwell and was diagnosed as having a blocked artery.
He was operated on and is recovering after what doctors said was a successful surgery.
LAOS lost its seats in Parliament in the 2012 national elections. It gained 2.7 percent in the May European Parliament elections, which was slightly less than was needed to elect an MEP.