Below is an overview of the mechanism that leads to cardiac myocardial infarctions (or heart attack). It took many decades for a basic understanding of this process.
The consensus at the beginning of the 20th century was that heart disease is a normal part of aging. In 1913, a 28 year old pathologist, Nikolay Anitschkow (or Anichkov), working at the Military Medical Academy in St. Petersburg, showed that by feeding rabbits cholesterol dissolved in sunflower oil induced vascular lesions closely resembling those of human atherosclerosis, both grossly and microscopically. Controls fed only the sunflower oil showed no lesions.
Another difficulty in understanding heart disease is that there are a number of factors involved. Researchers, practitioners and the public become attached to one aspect. Some argue passionately regarding one aspect of heart disease and become blind to other factors.