Arne H. W. Larsson, a Swedish engineer who in 1958 received the world's first implanted heart pacemaker, has died in Stockholm. He was 86.

A variety of pacemakers triggered Mr. Larsson's last billion heart beats, making him a medical marvel and a pioneer in one of the great triumphs of cardiology and electronic engineering. An estimated 3 million people, including about 1.5 million Americans, from newborns to centenarians, now use pacemakers.

Mr. Larsson died at his home near Stockholm on Dec. 28 of melanoma skin cancer that he developed two years ago, his wife, Else-Marie, said. His death was not announced until this week.

In 1958, scarring from a viral infection had disrupted the normal electrical circuit that linked his heart's chambers, and Mr. Larsson's heart could no longer contract synchronously. The heart beat as slowly as 28 times a minute, causing decreased blood flow to the brain and producing potentially fatal fainting spells, known as Stokes-Adams attacks.