Is a heart attack at 19 unheard of?

Unfortunately no : Diabetes is one of the risk factors for heart attack.Young people with poorly controlled diabetes may have heart attacks early.Added risk factors are high cholesterol, cigarette smoking, illicit drugs.Some people have an asymmetrically thickened heart muscle which can b associated w/ a bad heart rhythm causing sudden death.Although not unheard of, heart attacks in 19 yo isn't common.

Rare: Very rare, unless they have autoimmune disease or take methamphetamines or cocaine.

Not unheard of: Its rare - but we should distinguish between a true heart attack - blocked artery - and sudden cardiac death (usually cause by a problem with the heart electrical system). While some rare chronic conditions can produce a heart attack in a 19 year old like autoimmune disease or cholesterol disorders these are all rare - problems with the conduction/electrical system are more common at this age.