How a Heart attack Actually Happens

HEART ATTACKS IN THE US

According to the Centers for Disease Control and Prevention (CDC), cardiovascular disease (CVD) is the leading cause of death for men and women in the United States accounting for 1 in every 4 deaths and killing someone every 36 seconds. Coronary artery disease (CAD) is the most common type of heart disease and killed 365,914 people in 2017. About 18.2 million adults age 20 and older have CAD and 1 in 5 deaths from CAD happen in adults younger than 65 years old. 

Someone has a heart attack every 40 seconds in the US (about 805,000 per year). Of these, 605,000 are a first heart attack; 200,000 happen to people who have already had a heart attack; and about 1 in 5 heart attacks is silent, meaning that the damage is done, but the person is not aware of it.

HEART ATTACK MISCONCEPTION

I have anecdotally observed a common misperception, amongst both healthcare providers and consumers, about how a heart attack actually occurs – that a heart attack occurs simply because of a plumbing problem. The blame gets placed on cholesterol being too high. The argument is that cholesterol causes plaque to develop in an artery of the heart that becomes large enough that it eventually blocks off the artery and stops blood flow downstream. It surely sounds plausible but it’s not quite the case. 

HEART ATTACK EVENT REALITY

While plaque buildup inside the wall of an artery is certainly part of the problem, it’s interesting to note that 68% of heart attacks occur in a blood vessel that’s less than 50% blocked and 86% of heart attacks occur in a blood vessel that’s less than 70% blocked. An even scarier statistic is that you can pass a treadmill stress test with a 70% occlusion in the main artery to your heart and then leave the testing site to have a heart attack in the parking lot; it’s happened.

So we do require plaque in our arteries for a heart attack to occur, in a vast majority of cases. But, how can a majority of heart attacks occur in a blood vessel that’s less than 50% blocked? That’s where inflammation comes into the game. If you add arterial plaque and inflammation, you have the recipe for adverse cardiovascular event (e.g., heart attack or stroke) risk. 

Imagine what a pimple is like. It’s red, inflamed, irritated, and sometimes they will just open up on their own, spilling the contents onto…well, you get it. The contents of a pimple are in some ways similar to that of a plaque in our arteries (e.g., something that shouldn’t be there and a bunch of white blood cells). So, in your arteries, the big pimple-like plaque opens up because of heightened inflammation, both in the plaque itself and in the bloodstream.

Now the body looks at this plaque rupture like any other injury (like a cut on the hand) and wants to stop the bleeding. So the bloodstream calls in for backup to create a blood clot to keep things from getting worse. But, if this is in an artery that supplies oxygenated blood to the heart, this blood clot (thrombus) can block the flow of blood downstream to the heart muscle and the muscle tissue begins to starve for oxygen. The heart muscle tissue will die if intervention isn’t quickly made and this is where the importance of time comes into play in the event that someone is having symptoms of a heart attack. 

HEART ATTACK PREVENTION

The thrombotic event is how most heart attacks happen and how about 70% of strokes occur, as the same thing can happen inside the brain. Heart attack and stroke prevention is a multifaceted approach that targets the factors that both allow for plaque deposition to begin in the first place and that treat the underlying causes of measurable inflammation inside of the body.