John Heard passed away at the age of 72 last month, and now his cause of death has been revealed. The actor — best known for his role as Peter McCallister, the beloved dad in the Home Alone movies, and his Emmy-nominated role on HBO's The Sopranos — died after suffering a heart attack brought on by heart disease. John was found dead at a hotel in Palo Alto, CA, on July 21, according to sources close to the family. He underwent minor back surgery two days before his death, but officials says that did not play a role in his passing. John is survived by his two sons, John Matthew and Max, and his daughter, Annika.