Actor Puneeth Rajkumar, 46, today died of a heart attack. Known as Appu among fans and one of Kannada film industry's top actors, Puneeth was also a singer, producer and TV presenter. Not just Puneeth, a lot of celebrities have died of heart attacks under 50, a worrying trend. We pay tribute to the actor and ask experts about young Indians being deep in the grip of heart diseases.