John Koko, the bassist-singer with The Makaha Sons, has been hospitalized at Kaiser Medical Center with heart-related problems.

He underwent valve-related procedures Saturday night and is in good spirits, according to brother Jerome Koko, who also is in the group with Louis "Moon" Kauakahi.

The group had to cancel two weekend appearances — one in Waikiki, one in Hilo — and will postpone its Thursday night performance at Moonlight Mele on the Lawn at Bishop Museum this week, to an alternate date to be determined later.

Under doctor's orders, Koko is not accepting visitors at this time. The Makaha Sons hope to resume its tour schedule at the end of the month.