How did Dmitri Shostakovich die?

Shostakovich died at 6:30pm on August 9, 1975, from a heart attack associated with the lung cancer he suffered from. The official announcement ascribed the cause of death to longtime disease. At the time, Shostakovich had been suffering from a number of other illnesses as well, including terminal amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease), incorrectly diagnosed as a rare form of poliomyelitis.