Is this what you are referring to:
http://www.hebrewbooks.org/pdfpager.aspx?req=21194&pgnum=504
(I think it’s a brain not a heart, though it’s not relevant to your question.)
To answer your question, I have seen people claim that R’ Gedalia Nadel and R’ Mordechai Gifter said that the Chazon Ish read medical journals. Google chazon ish read medical journals and you will find these claims. Seeing as neither R’ Gifter nor R’ Nadel is still alive, I don’t know how you can verify the claims, so you’ll have to decide for yourself whether to accept them or not.