So one day last week, I awoke to the news that Bernie Sanders had had "heart surgery." It turned out, not to be true, which is a very good thing, since actual heart surgery would have certainly meant the end of his presidential campaign. Heart surgery is a very big deal indeed, generally involving a fairly arduous and months-long recovery.

"Honestly, the people who should be most worried right now are the campaign staff who will have to keep up with him now that the arteries are fully open."

What he did have was a procedure to insert stents into a coronary artery. This is something I know a fair bit about. I retired recently from a 36-year career as a Cardiac Rehab Nurse. Cardiac Rehab is education and exercise for cardiac patients. About half the patients I saw were stent patients. I explained the procedure to them before it was done, taught them about self-care before discharge, and supervised a longer-term exercise program to help them make a complete recovery and reduce the chance of recurrence. This stuff was my life for 36 years.

My next question was: What had precipitated this? The news said "chest discomfort." A few days later, the somewhat more serious words "heart attack" were used.

Let me put this into context and give a little background. Most heart disease in the developed world is what we call Coronary Artery Disease (CAD). This means fatty deposits that build up in the walls of the coronary arteries—the arteries that supply blood to the heart. This build-up is a slow and gradual process that can go on for many years before it produces symptoms. When symptoms do occur, they can be quite sudden, even though the process behind it has not been sudden at all. Most people experience pain or pressure in the chest, often radiating to one or both arms, to the throat or to the upper back.

If the blockage is incomplete, we call the onset of symptoms "unstable angina." If the blockage is complete—a total cut-off of blood flow—we call that a "myocardial infarction"—or, more commonly, a heart attack. In the old days, when I started my career, the difference was very consequential because a heart attack meant injury to the heart muscle that left a person permanently impaired. Even today, people who don't get quick care (often for lack of health insurance coverage!) still suffer that kind of permanent damage.

But, for those who do get quick care—as the Senator did—the difference matters a lot less. We now have the technology to re-open a blocked artery and, if done quickly enough, eliminate the lasting damage that used to result from heart attacks. The watchword of people in this business is "time is muscle" (heart muscle, that is). The sooner you can re-open the artery, the more heart function you save. Soon enough, as appears to have been the case here, and you save it all.

So, what does this mean for the Senator's campaign and fitness to be president? Frankly, not much at all. While I don't know all the details of what happened to Bernie, I know enough to say I would expect a return to full, unrestricted activity within two weeks after the event. So I have no worries about his ability to return quickly to the campaign trail.

Remember, those arteries had been narrowed for a long time. Even with narrowed arteries the Senator has been keeping up a pace that most younger people couldn't hope to match. Now, they are wide open and he's probably had no significant heart damage. We know from his high school track performances that he's genetically designed for endurance. Honestly, the people who should be most worried right now are the campaign staff who will have to keep up with him now that the arteries are fully open.