Skip to 0 minutes and 5 secondsHeart attacks are the culmination of many of the processes we've been learning about in the sessions previously. We've learned about the formation of atherosclerosis, atherosclerotic lesions, within the arterial circulation. And, unfortunately, particular hot spots for the formation of these lesions are coronary arteries. Now coronary arteries are the blood vessels that supply the muscle of the heart with oxygenated blood. So they're responsible for supplying the energy needs of a very metabolically activity tissue. And when that supply is diminished, this affects the function quite dramatically and can lead to the ischemic damage or cell death. And cell death can be very damaging to the function of the heart. Now heart attacks are actually very common, very prevalent.
Skip to 0 minutes and 57 secondsWithin the UK, for example, each year more than 100,000 heart attacks are suffered. And they're responsible for about 80,000 deaths. That's in a population of around 70 million people, to put this in perspective. It's also estimated that around 1.3 million people in the UK live with the aftereffects of having had a heart attack. So this has changed, in many respects, the way we look at the long-term treatments of individuals who suffer these types of conditions, because quite often they do survive but then go on to suffer from other long-term effects.
Skip to 1 minute and 34 secondsNow the reason why this occurs is principally because platelets are activated and form a thrombus at sites of an atherosclerotic lesion either because the lesion itself is sticky - often they have collagen on their surface, which, as we've heard earlier, the platelets like to stick to - but also they rupture. A thrombus forms, and because these vessels are actually quite tiny, they can have quite damaging effects very quickly. The acute symptoms of a heart attack include crushing chest pain, shortness of breath, nausea, vomiting. And approximately 50% of deaths occur within one hour of the initiation of this type of event. And it's for that reason why very prompt action is essential if the patient is to survive.
Skip to 2 minutes and 21 secondsThe consequences of a heart attack can be catastrophic. For example, it can lead to ventricular fibrillation, which will ultimately lead to a loss of cardiac output. The heart is unable to coordinate contraction properly, and blood flow ceases. And clearly, this is fatal. Many individuals, however, do survive. The damage to the heart, unfortunately, is irreversible. The cells that the heart is composed from, the contractile machinery within the heart, is unable to repair itself. So what happens is that the cells that have died or the cells that have been lost within the heart become replaced with scar tissue, often collagen. And whilst this holds the tissue together, it is not functional. It is unable to contract. So the heart becomes floppy.
Skip to 3 minutes and 9 secondsIt becomes unable to meet the demands of the body. This ultimately leads to a process known as heart failure or congestive heart disease, which is a topic that's going to be covered in a different session.
Heart attacks (Part 1)
Heart attacks are caused when a thrombus blocks the blood vessels that supply the heart muscle. In this video Professor Jon Gibbins discusses how and why heart attacks occur, and also looks at symptoms and survival statistics.
You can download the Week 2 supplement, which contains additional images and descriptions to help you understand the topics covered in this video.
British Heart Foundation resources
You can find out more information about this topic in the following booklets produced by the British Heart foundation: