A team of scientists and medical experts at Michigan State University have discovered a symptom that if found could be a sure sign that a heart attack is imminent.
Led by Professor of Medicine Dr. George S. Abela, the team examined materials that were blocking the coronary arteries and discovered that it was in fact cholesterol, but as large crystals.
By looking at over 240 different emergency rooms and examining cases from them, they found that this hardened cholesterol was present in over 89% of cases.
Cholesterol crystals are a particularly nasty side-effect of plaque build-up inside the heart. Made from fat, calcium and other substances these crystals can start to expand as they harden within the arteries.
"In previous studies, we showed that when cholesterol goes from a liquid to a solid, or crystal state, it expands in volume like ice and water," Abela said. "This expansion inside the wall of the artery can tear it and block blood flow causing a heart attack or stroke."
To try and get to the bottom of how these crystals are causing so much damage they went directly into over 240 emergency rooms across the US.
Once a heart attack patient was admitted they would suction out the crystals and examine their size and hardness. What they found was that large clusters of crystals had been able to break through the plaque and walls of the arteries and had even entered the heart itself.
In addition to the physical damage caused by the crystals tearing through the arteries they were also able to confirm that the crystals activated the production of inflammation molecules known as Interleukin-1 beta which can inflame and aggravate arteries.
While all this might sound quite scary there are two piece of very good news to come out of the discovery.
The first is that now they have a better understanding of a key warning light before a heart attack they can do more to combat it.
"Now that we've shown how extensive cholesterol crystals are irritating and blocking off these arteries, treatments that dissolve these crystals may be used to reduce heart damage," Abela said.
The second is that it reinforces what medical professionals have been preaching for years which is that continued exercise and dietary choices have a proven ability to reduce the formation of these crystals in the first place.