Reports say Japan's 84-year-old former Empress Michiko has a heart problem that needs monitoring, but can go ahead with a planned trip to the ancient capital of Kyoto with her husband, who recently abdicated as emperor.

NHK public television, quoting palace officials, said Monday that doctors found Michiko has heart valve abnormalities and an irregular pulse.

Doctors discovered the abnormalities in a heart examination on Saturday after a regular health checkup showed an increase in cardiac hormones.

NHK says Michiko has experienced shortness of breath after her daily morning walks since earlier this year.

However, it says she will accompany her husband Akihito to Kyoto as planned, as part of his abdication rituals.