You might think the nation's biggest heart organizations would issue their guidelines based on research and evidence.

But you'd be wrong.

An alarming new study finds that in many cases, the American Heart Association and the American College of Cardiology issue guidelines based on nothing more than anecdotal evidence or the say-so of some expert.

The study, published recently in the Journal of the American Medical Association, looked at 20 years of guidelines from both organizations, and assigned each one a level – A, B or C – based on the strength of the research behind it. An "A" meant the recommendation was backed by strong research, while a "C" meant there was no real supporting evidence beyond anecdotal.

By the time they were done, they had graded 2,711 recommendations from those organizations – and just 12 percent received an "A."

On the other hand, 1,246 of those recommendations – 48 percent – had a level of "C." But let's call that what it really is – a big, fat "F."

Just to be clear, these are guidelines being issued by the nation's two most influential cardiology groups and meant to influence the kind of care you and I get from our doctors when it comes to our hearts. And nearly half the time, the guidelines have been issued with no real evidence to support them at all.

Now, if you want to chalk that up as accidental, careless, or just plain lazy, go right ahead. But I only wish it were as simple as that.

You see, the main reason behind many of these guidelines is a desire to push a new drug or surgical procedure. Top dollar is still the bottom line. 

Just listen to the editorial accompanying the study, written by Dr. Terence M. Shaneyfelt and Dr. Robert M. Centor of the Department of Medicine at the University of Alabama School of Medicine in Birmingham.

"Guidelines have often become marketing tools for device and pharmaceutical manufacturers," they wrote. "Only when likely biases of industry and specialty societies have been either removed or overcome by countervailing interests can impartial recommendations be achieved."

This is disturbing, but it's not exactly surprising. These same groups have been giving us bad advice based on flimsy research for years. Their guidelines have encouraged Americans onto the same carb-loaded low-fat diets that are making us obese, diabetic, and more prone to the heart diseases that these groups are trying to prevent.

But now we know the reality of the situation. The only question now is whether they'll do something about it.