Dance of the Drunk Mantis is a 1979 Hong Kong kung fu comedy film directed by Yuen Siu-tien's real life son Yuen Woo-ping, this was Yuen Siu-tien's final film appearance before his death on 8 January 1979 from a heart attack, Myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing damage to what?