I’m trying to find information about the long-term effects of malnutrition on cardiac muscles. I know that emaciation weakens the heart muscle and have read of “sudden cardiac death” and increased risk of myocardial infarction, but haven’t had much luck with finding detailed descriptions/statistics. The hypothetical type of case that I’m interested in is a female who received good nutrition as a child but became malnourished and underweight (with the accompanying amenorrhea) around age 13, staying under recommended weight for at least five years, while exercising several hours a day, seven days a week. (Basically, anorexia cases). How reversible is damage of this sort? Are there any specific vitamin supplements that would be especially beneficial in a case like this? Also, I’d be very interested in reading explanations of the exact physiological reasons/processes for “sudden cardiac death,” not that I’m doubting that it’s a risk, it’s just that most of the resources I’ve found have been a little vague on exactly what happens to cause it. Any information is extremely appreciated, thanks for your time.