Welcome to Dr. Warrick's podcast channel. Warrick is a practicing cardiologist and author with a passion for improving care by helping patients understand their heart health through education. Warrick believes educated patients get the best health care. Discover and understand the latest approaches and technology in heart care and how this might apply to you or someone you love. Hi, my name is Dr. Warrick Bishop and welcome to my podcast and videocast station. Today I'd like to talk about how do heart attacks occur? Well, of course, why do we bother? The answer is because it's important. Heart attack is a really big deal. It accounts for 9 million deaths per annum on a global scale. In the Western world, it accounts for one in four deaths. In the United States of America, every 40 seconds, someone dies from a heart attack. And one of the most compelling statistics of all is that two out of 10 people who have a heart attack are 65 years of age or less. So what is heart attack all about? term that's a layman term it's not the term we use in medicine the term that we use is a more scientific term which relates to a blockage of the artery and the heart muscle not getting enough blood we call that myocardial ischemia myocardial pertaining to the heart muscle ischemia meaning lack of blood or myocardial infarction myocardial again pertaining to the heart muscle infarction meaning death from lack of blood flow but what occurs occurs in the artery and the bit that we're most interested in today is the build-up of plaque in the artery think of rust in a pipe plaque in the artery well what is plaque well rust in the pipe in your house is really a breakdown process and I guess there are some similarities in the body. What transpires is that for various reasons there's wear and tear within the arteries as you might get wear and tear in the joints of your body. The blood rushes past and there's movement of the arteries particularly the heart because it's beating all the time and there can be focal spots of wear and tear. That kicks off a repair process which is localized. And that repair process is driven by factors that have caused irritation to the lining of the blood vessel. That lining of the blood vessel is like the Teflon within our blood vessels preventing components of the blood from sticking. and clogging our arteries up so we have this amazing layer of cells within the arteries which we call the endothelium or the inside lining and that inside lining if it gets traumatized in a local spot maybe by movement maybe by blood pressure must send out some messages to the body which sets off a chain of events, bringing cholesterol into that area for repair processes. So in this local spot of wear and tear within an artery, cholesterol moves in as it does. There are signals from within that location, letting the body know that cholesterol is now in a spot where it necessarily wouldn't be. It's generally put there by the so-called LDL or low density lipoprotein, the so-called bad cholesterol, is the one that gives up its cholesterol component into the tissue of the blood vessel. As markers, as messengers, as chemicals within the wall of the artery are liberated with the cholesterol being there, then there are white cells which are our body's response or inflammatory response, immune response cells that move in following the cholesterol. Some of those white cells are called macrophages. And if you think of a macrophage as sort of a cleaning agent, it's a big fat cell that gobbles stuff up. It moves into the artery to gobble up the redundant cholesterol that's starting to be deposited. The trouble is that if cholesterol is moved in there to any degree, that the macrophages get in and they gobble it up, but there's still plenty left. They eat so much, they swell to a point that they burst. They literally explode from eating too much fatty cholesterol within that artery. But as they explode, because they're the garbage guts of the immune system, they have enzymes within them. gets spilt where they've ruptured, where they've exploded in that artery wall. Those enzymes obviously have destructive properties and cause local micro scarring. And that micro scarring creates the architecture that subsequent deposition of calcium can occur on. And so now we've got this process occurring within the artery under that a thin lining, which is our Teflon lining within the artery. We've got fatty components, which are the cholesterol. We've got some inflammatory cells, our white cells, our macrophages. So there's an inflammation process occurring. We've got some scarring and calciums moving in there. And we've now got the components of a plaque. Now, sometimes the fatty bit can all be gobbled up and a little bit of scarring might occur and not much further happens. It can be quite benign. And the repair process satisfies exactly what the body needs. But sometimes it can be a bit out of balance and fatty cholesterol tissue can continue to be deposited into that plaque region. Now, the problem is if that fatty tissue continues to be deposited and the inflammation process occurs, then the covering of that fatty plaque, that fatty inflamed plaque is a thin fibrous cap and growth of that fatty plaque together with inflammation may lead to a small bleed into that plaque or something that distorts. the quality and nature of that plug so that it can rupture and it ruptures inward into the artery. Now, if the contents of the plaque rupture into the inside of the artery, what we call the lumen of the artery, then what we find is that the contents of the blood are mixing with the contents of the plaque and these were never meant to come together. Remember, we had that Teflon lining within the artery preventing the components of the blood clogging up well in the absence of that teflon lining with the contents of the plaque merging mixing with the contents of the blood it sets off a reaction to form a clot because the body thinks that it may be under attack or bleeding and to protect blood loss forms a clot. Well, of course, if that's occurring within an artery and an artery is only a couple of millimeters across, that clot can suddenly block that artery. And before you know it, no blood flow going down that artery. Suddenly there's myocardial ischemia, i.e. the muscle of the heart short of blood. And if that's left for too long, myocardial. infarction. It is that irritated ischemic lack of blood flow muscle that can become irritable and flip into an electrical rhythm which can kill the individual affected by the process. Well I hope that makes some sense but the bit that's probably really concerning and the bit I really want to underline for you is that often is the case that people can be perfectly well before their heart attack. Well, why does that occur? Well, the answer is that the fatty, inflamed plaque may not be limiting blood flow in the artery up until the point that it ruptures. And so we see that about 40% or even a bit more of all heart attacks occur on plaque. that is not limiting flow in the artery prior to the time that it ruptures. This means that the person can feel perfectly well right up until that second where the artery closes off. This is why cardiac health, cardiovascular maintenance, cardiovascular well-being, knowing your risk, dealing with these issues, this is why it's so important because it can be completely silent. until it rears its ugly head. And remember, two in 20 people, two in 10, 20% of people that this occurs in will be under 65 years of age. That's how heart attack occurs. I hope you've learned something today. If you've got any queries or questions, drop us a note at the usual email address. Till next time, of course, I wish you the very best. And please, don't drop down from a heart attack. Goodbye. You have been listening to another podcast from Dr. Warrick. Visit his website at drWarrickbishop.com for the latest news on heart disease. If you love this podcast, feel free to leave us a review.
