Myths About Myocardial Bridges

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Myth: “MBs cannot cause significant symptoms because they only compress the artery during systolic phase i.e. when the heart squeezes, when only 15% of blood flow takes place, whereas 85% of blood flow takes place in the diastolic phase i.e. when the heart expands/relaxes.”
This has long been proven false. It is a very common myth among doctors and has been used as a reason for denying surgery. However, it is easy to debunk because it has been proven wrong by numerous papers including by Stanford and by Daoud et al (2012) listed below. The missing fact that doctors don’t realize is that compressed arteries are slow to open, they don’t just spring back open immediately when the pressure on them is gone. Specifically, after the MB squeezes and compresses the artery, like pinching a plastic tube, when the heart then relaxes the compressed artery actually stays compressed long into the diastolic phase—in many cases through most of the diastolic phase—which again is when 85% of blood flow is supposed to be taking place. So during all this time when the artery remains compressed during diastolic, blood flow is cut off. To quote Dr. Schnittger:

“When the relaxation phase starts the vessel is so compressed that it does not reach full size until very late in relaxation and therefore has limited blood flow overall when it is supposed to be fully extended. Doctors do not seem to understand this. But it has been published in so many articles.”

Myth: “MBs are very common and most people who have them don’t have symptoms, so the chances that my MB is causing symptoms are low.”
Completely false. This myth is frequently repeated by doctors based on a misinterpretation of the statistics. It is true that MBs in general are relatively common. It has been stated that 25% of autopsies reveal MBs. However, less than 10% of angiograms show MBs reducing blood flow. The vast majority of MBs are miniscule, just a few millimeters in length, producing few or no symptoms and going undetected. On the other hand, the MBs that are typically detected and reported by the radiologists who read your test images are those starting around 2 cm / 20 mm and upwards to 5, 6, 7, and even 8 or 10 cm. These much larger MBs typically do produce significant symptoms. So the very fact that you heard about your MB from your doctor makes it highly likely that it is significant enough cause symptoms. If your MB was not large enough to cause symptoms, the radiologist likely would not have even reported it, so your doctor would not have even known about it or notified you about it.

Myth: “MBs do not cause significant symptoms”
This has been proven wrong in countless studies over many decades, see list of studies at the end. The science has long been settled, MBs can and do cause significant symptoms. The medical literature now has moved on to investigating the best ways to diagnose and treat the symptoms. If your doctor is telling you MBs cannot cause symptoms, it is a sign he is far behind the learning curve and you would be best to find a new doctor, or present the doctor with the studies that contradict his assertion below.

Myth: “You can’t be an athlete/athletic or workout if you have an MB”
Completely false. Numerous people with MBs on this site are current or former triathletes, competitive cyclists, weightlifters, basketball players, and so on. At the same time, there are others who have difficulty walking a few blocks down the street. It all depends on the situation.

Myth: “MB symptoms only show up when you’re really exerting yourself.”
Completely false, it can actually be the opposite, it depends on the person. This was actually said by a “Top Doc” Dr. DeRose at Montefiore Hospital in New York. Many people report that their MB symptoms are worst when they are just sitting, not moving at all, and actually improve when they are at the gym or out cycling. For example, one member of this site reported that he is a competitive cyclist, and yet he passed out sitting at his computer writing emails. On the other hand, others report that they cannot get up and walk more than 10 minutes. MBs are all different depending on the length and location, so there is no single rule about exertion and symptoms.

Myth: “You’re too young to have a heart issue.”
Totally false. Stanford believes MBs exist from birth, and anyone at any age can have major symptoms. On this Facebook site are families with kids as well as people in their teens, 20s and 30s who have had major symptoms and had unroofing surgery.

Myth: “Unroofing doesn’t fix all the symptoms of MBs.”
This statement is based on a misunderstanding. There are different categories of symptoms related to MBs: direct and indirect. First, symptoms directly caused by the MB (ex. dizziness, shortness of breath, feel of something pressing on the chest, squeezing down the arm, etc.) are indeed fixed immediately by unroofing, and that alone is worth surgery. On top of that, other symptoms are caused by indirectly by the MB, namely by endothelial dysfunction (ED) which is a byproduct of MBs, take time to heal but do improve slowly. It’s critical to note that endothelial dysfunction can only *begin* to heal with unroofing, many doctors do not realize this point. As long as the band of muscle remains there, endothelial dysfunction is only getting worse, and only when it's gone can the lining of the artery can start to rebuild and regain function. It can take a year or more but improvement of ED definitely occurs as many people on this FB site have testified to based on their own experience. Vasospasms are far milder and fewer than before. So in reality, the fact that unroofing doesn’t immediately fix all the indirect symptoms of MBs is one more reason to have unroofing – so that healing of those indirect symptoms can begin.

Myth: “You can’t die from a MB.”
There is a long list of medical literature that connects sudden deaths to MBs, including MBs in combination with other heart issues. The MB center at Stanford started after Dr. Schnittger found a study in which a 43-year-old professor died on a treadmill with no other causes evident except a MB. Another study reports a similar case from Brazil. Studies have shown MBs can cause heart attacks. So it seems logical that an MB could lead to death if severe.

Further, there is not a simple black-and-white answer because MB compression and loss of blood flow combines with that caused by plaque nearby and also by endothelial dysfunction that often appears inside them to produce amplified symptoms.

Myth: “Myocardial bridges are always straight, the artery would not be curved on a CT scan.”
Completely false—and baffling. This was actually said by a “Top Doc” in New York. In fact the opposite is true, bridged arteries often end up causing kinks and have major curves, as research papers have reported.