Arthur Agatston, M.D. author of the hugely successful South Beach Diet and its spin-offs, has now produced The South Beach Heart Program, The 4-Step Plan That Can Save Your Life. The book includes the basic South Beach diet program — he calls it here “Heart Healthy Eating” which many St Louisans I know follow for two-week periods to lose vacation weight. In addition, the book prescribes:

* Regular aerobic and core exercise

* Advanced diagnostic testing (He invented one called the “Agatston test.”)

* The latest heart-protective medications.

Agatston explainsthat the Holy Grail of cardiology looks for the so-called seventy percent to eighty percent blockage and then perform angioplasty or bypass surgery. Agatston and his ilk look, first of all, for preclinical disease with imaging the heart and at the calcium score. In the early stages of disease they do conventional blood testing as well as advanced testing. They treat most of the targets, and monitor what he calls the sub-clinical diseases. With this preventive approach and early targeting, he claims to be seeing heart attacks and strokes disappearing from certain clinical practices.

But don’t expect the breezy, easy read you found in his diet books. This is deeper, more serious medical writing.

His voice and tone are those of a groundbreaking cardiologist, as opposed to the kind of repairmen cardiologists he calls “plumbers.”

His aim is ambitious: to help the baby boomers who are approaching heart-attack age avoid heart attacks by taking early action.

He explains how things have changed: “Pathologists first examined the arteries of heart attack victims; they reported that they were hard and inflexible…A closer look revealed that the artery walls were not just stiffer, they were also clogged with a yellowish, waxy substance called plaque.

Cardiac researchers also correctly noted that most heart attack patients had something else in common: One or more of their coronary arteries was blocked, preventing bloodflow to the heart muscle. Their first mistaken assumption was that plaque builds up inside an artery steadily over time, gradually narrowing the opening until it closes, blocking bloodflow. Second, after observing a blood clot at the site of most blockages, they theorized that the clot had formed after the plaque had sealed off the artery causing bloodflow to become stagnant … In fact they were mistaken … Here’s what they missed: There are two kinds of plaque — soft plaque and hard plaque. It is the soft plaque which is prone to rupture that is most dangerous and that most often causes a heart attack.

It’s like a small pimple protruding from underneath the delicate inner lining of the artery. The soft plaque is filled primarily with cholesterol. Suddenly, with no warning, the small plaque-filled pimple can burst open, puncturing a hole in the lining of the artery and exposing the contents of the soft plaque to the bloodstream. A blood clot then develops at the sight of the “injury” as part of the healing process. This clot is what most commonly causes obstruction of bloodflow; the clot is not the result of obstructed bloodflow as was previously thought.”

Agatston claims his test can diagnose heart disease years before it causes symptoms and consequently prevent a heart attack from ever happening.

DR. ARTHUR AGATSTON, author of “The South Beach Heart Program,” published by Rodale Books.

11 a.m. on Sunday, Nov. 11.

Admission: $15 or free with festival series ticket.