There is a book about this topic by Dean Ornish, (The Spectrum) who studied some patients who have the worst cases of atherosclerosis. Most of them needed a heart transplant.
The good news is that some of these patients improved so much that they no longer needed a transplant. These are a few quotations from the book:
“Our studies show that with significant lifestyle changes, blood flow to the heart and its ability to pump normally improve in less than a month, and the frequency of chest pains fell by 90% in that time.”
“Within a year on our program, even severely blocked arteries in the heart became less blocked, and there was even more reversal after 5 years. That’s compared with other patients in our study, in which the heart just got worse and worse.”
The lifestyle changes are walking at least half an hour a day, and doing some yoga and meditation for stress reduction.