Heart attack
A myocardial infarction, also known as a heart attack, occurs when blood flow blocks a part of the heart, destroying the heart muscle. According to some health experts, this phenomenon can take place during sleep, but in some cases, it will wake the patient up before other severe complications occur.
Unfortunately, most of the time, people will die not only because it affects a large part of the heart tissue and the heart won’t be able to pump enough blood to the whole body, but also because they can’t seek proper medical care faster (because they were sleeping).