Prince Mikasa, uncle of Emperor Akihito, has been hospitalized after partially losing consciousness at his home Tuesday evening, the Imperial Household Agency said Wednesday.

The 97-year-old youngest brother of the late Emperor Hirohito, who is known posthumously as Emperor Showa, fell into a semiconscious state around 6:30 p.m. but was back to normal before his doctor made a house call later, according to the agency. Initial examinations found no abnormalities.

The prince underwent heart surgery in July last year and has been rehabilitating at his home.