I Have A Friend Who Has A Defibulator In His

I have a friend who has a defibulator in his heart and it went off yesterday and he will have to have an ablation again to correct his condition - if it doesn't work he may be a candidate for a heart transplant. I didn't realize it was this serious - can a person with a debibulator live a "normal" life or will they inevitibily need a heart transplant?