Yeah, I will also agree that the art here is beautiful, and that is some of the most insightful rendering of panic attacks I've seen. Well done, Hattori-sensei.
But outside of that, my god is all of this ludicrous. ><;
First off, as many others have pointed out, they gave no explanation at all for why Shiro couldn't get the artificial heart. The changes in perspective are rather confusing and not indicated well at all (resulting in e.g. the confusion over who's studying what). Then there's the fact that the doctor's solution to Shiro's panic attacks is to give each of them access to her heart monitor app? And of course there's the typical bad yuri trope-a-thon of obtuse ignorance of each other's feelings, and heedless self-endangerment because one friend feels bad. Even their names reveal the fact that they're little more than vague outlines of characters to fit into a yuri Story A.
But that said, again the art is beautiful and the story didn't go in the horror direction I kind of assumed after that opening page, so let's hope it finishes strong.