No this isn't an EKG; it shows the ups and downs of presidential approval fortunes and vicissitudes over the past 70-odd years.
Some points worth noting:
1) We're always hearing about Trump's "record low" ratings. As you can see above, there is clearly NOT true, just more "fake news" from Fake News.
2) The two most popular presidents, at least at their high points, were Father/Son Bush. Dad hit 87% and son hit an astronomical 89% approval.
3) Barack Obama was generally, much as Trump is now, an unpopular president but throughout his 8 years in office.
4) The all-time low points of these post-war presidents were:
G.W. Bush: 25%
5) Trump is the only president to have been sworn in with a less than 50 rating according to Gallup, Trump's approval was only 45% on the day of his inauguration. His approval rating has been relatively flat compared to other presidents; at least, thus far, He hasn't slipped much despite the undeniably negative effects of incessant media and institutional hostility
NOTE: Rasmussen has Trump's approval rating at 45%, not the 39% reported today
by Gallup. Gallup polls "all adults" and Rasmussen polls "likely voters."
Did you find any surprised in looking at these charts?
The interactive version of this chart can be found here