Heart attacks (Part 2)

There are a number of different ways that coronary heart disease that ultimately leads to a heart attack can be diagnosed. This includes the ECG methodology that you’ve learned about already. But also angiography is a technique that’s commonly used. This involves the infusion of a dye into the circulation, a dye that is recognised or lights up on an x-ray, and then a rapid series of x-rays are taken to visualise the circulation within the heart. And this can lead to the identification of a region where blood flow is restricted or completely blocked. And this can give a lot of information about the type of strategy that would be used for treatment.

Other types of imaging techniques that are used for this and other areas of cardiovascular disease include magnetic resonance imaging and echocardiography, which enables the size, structure, and function of the heart to be monitored. Now clearly the occurrence of a heart attack is the endpoint of a long-term chronic disease. But we can do a lot to reduce the risk of developing a heart attack in individuals who are at risk. So these may be individuals who’ve already had a heart attack or they have a number of high-risk factors that they may go on to develop a heart attack later on. So these include inhibiting the processes that ultimately lead to the thrombosis in the first place.

And these are the types of drugs I introduced earlier, thinking about anticoagulant drugs or also drugs that target platelets and reduce the likelihood of them becoming activated. And these will be used long term as a prophylactic treatment to try and reduce the risk of heart attacks occurring. In individuals unlucky enough to suffer from a heart attack, it’s important that the thrombosis is removed as quickly as possible. This isn’t always possible, but an approach that is frequently used and often successful is the administration of a protein intravenously, a protein and its tissue plasminogen activator, tPA. And this is a natural protein. It’s normal job is to activate a process that leads to the production of an enzyme known as plasmin.

Plasmin’s role is to digest fibrin, and it’s part of the normal healthy process that enables blood clots to be cleared once they’re no longer needed within the normal context of injury. But remember, this thrombosis occurs within the blood vessels. So the tPA is infused into the blood vessel and, in time, enables the fibrin to be digested and the thrombus to clear. It’s very important that this is administered very quickly before too much damage is done. And so this is a front-line therapy that will be administered often before admission to hospital.