Michael Lohan, estranged father of troubled actress Lindsay Lohan, was admitted to the hospital last week after experiencing chest pains on Friday.
TMZ.com reports that he is under observation at an as-yet unidentified medical facility after doctors there found blood clots and administered medication to dissolve them.
Lohan also underwent surgery in December to unclog an artery.
Once his condition has stabilized, Lohan will most likely return to Palm Beach, Florida for the domestic violence intervention program he was ordered to complete by the court. He will be released on March 16.