Hollywood Heartthrobs

Hollywood heartthrobs have been a staple of the movie industry since the era of silent movies. Who can forget the greats of the 20’s, 30’, 40’s. Since 1950 interest in these celebrities has reached a misbegotten world-wide pitch. This harebrained engrossment should instead be placed on clinical anatomists, those individuals who teach medical students all about esoteric parts of the body that appear on “the Boards”. For example, an ECG recording of a normal heart is represented by the PQRST waves. Which indicated structures in the image are indicated by the P wave?

Postscript: If answering this question correctly at a happy hour trivia bowl at a bar does not get you a Saturday night date, nothing will. Or perhaps, you may consider going to a bar that does not ask this type of question.

Depolarization of which structure is responsible for the P wave in a PQRST complex?