The cause was hypertensive cardiomyopathy, a heart disorder, his agent, Michelle Findlay, said. The band announced that Mr. Bell had remained in the United States after their latest concert for a routine medical checkup and minor surgery before returning to Ireland.
The Chieftains, led by Paddy Moloney, have been acclaimed for their role in the revival of Celtic music. Mr. Bell, a virtuoso of the Celtic harp, played the piano and electric keyboard as well as the oboe, English horn and hammered dulcimer. He was also a composer and a classical musician on several instruments.
The band, currently appearing as a quintet, was visiting the United States as part of its 40th anniversary tour. NY Times