Complex sentence: A heavy smoker for many decades, Hunter had 3 heart attacks and a heart operation over a number of years (his first in 1989) and was found to have a precancerous lesion on his larynx in 1992.
Split into simpler sentences: A heavy smoker for many decades, Hunter had 3 heart attacks and needed a heart operation. Over a number of years (his first in 1989) and was found to have a precancerous lesion on his larynx in 1992.