心梗 is the everyday short form of 心肌梗死 (myocardial infarction). Doctors, news and everyday speech all use 心梗. Pair with 脑梗 (nǎogěng, stroke) as the two big 'vascular-blockage' emergencies.
memory
梗 means to block / clog. 心梗 = heart-clog, 脑梗 = brain-clog. The vivid plumbing image is why the short forms caught on.
