Stable angina is a very common problem in the UK due to coronary heart disease and the diet and the health and fitness of the current demographics in the UK. What actually happens is the coronary arteries around your heart, the small blood vessels feeding the heart itself and feeding the heart muscle start to become flared up. It’s a little bit like limescale building up on pipes. What’s happening is the plaque or the fats that you eat start to build up on the inside of the coronary artery and that narrows the bowl of the coronary artery. And where you get a narrowing, you get an increase in pressure, because if you narrow the bowl, you increase the pressure inside the bowl. Which is why your GPs will always take your blood pressure, especially when you get over 40, because they’re looking for an upward trend in blood pressures, indicating flaring up of arteries increasing blood pressure. What you have got to understand is, that does not ever go away. Once it starts to build up and it starts to build up roughly from the age of four through the rest of your life, you can’t remove it. It doesn’t clear, it just gets worse and worse over time.
And patients, when they get older, not necessarily that old, into their late 30s, as this plaque starts to build up due to their poor diet and what they consume and smoking and everything else has an effect on it, the narrowing of the bowl restricts the flow. And when your heart requires more oxygen because it’s working harder, for instance, when we start walking uphill, exercising, doing anything strenuous, your heart muscles starts to call for more oxygen, your heart beats faster to produce that, but the flow can’t get past the narrow passage of the flared up artery. And what happens is, the muscle becomes starved of oxygen and starts to get a cramp. So, basically, angina pain is cramping of the heart muscle, which gives you the pain, central pain to the middle of the chest, which is hard to distinguish if not impossible to distinguish between a heart attack. But remember, a heart attack, angina, and cardiac arrest are all totally different things. They can all lead to each other, but they’re all separate occurrences. We are talking about stable angina. The reason it’s called stable angina is because we know what brings it on and we know what takes it off.
We know that strenuous exercise, walking uphill and that type of thing, when the heart has to work harder will bring that pain on. But we also know that if we stop, we relax, we rest, the heart slows down, the blood flow is reduced, so the pain disappears. It’s stable, we bring it on, we can take it off. If that becomes more common and it starts to happen with less and less exercise, we know those coronary arteries are beginning to get more and more flared up, and people who are suffering from angina regularly will be on medication. One of the most common medications you will come across is GTN, Glyceryl Trinitrate, normally in a little red bottle with a metered dose when they spray it. There also may be on the same stuff as a tablet, or the same medication in tablet form, which they put in their mouth, behind their lip, against their gums, which absorbs slowly into their bloodstream. And what the GTN does is, it dilates the blood vessels, it restricts or it actually reduces the restriction of the blood vessel, it slackens off the muscles that constrict the blood vessels increasing the flow of blood to the muscle of the heart taking away the pain.
One of the side effects of GTN is a splitting headache. It will give the person who is taking the GTN a very, very pounding headache, which is common that will happen on all casualties or nearly all casualties that have used GTN. But another side effect that you need to be aware of is a vasodilator. It dilates blood vessels which drops blood pressure. If GTN is taken in too great a dose, it’s very common for the patient to actually pass out or faint due to their dramatic drop in blood pressure. So it has to be taken with caution, by the patient that it’s been prescribed for, and we have to make sure that we look for any side effects. So if somebody has collapsed in a shopping centre or walked out in the street and they have angina, it can quite often mean that the pain came on, they took a little bit too much of the GTN drug and passed out due to the vasodilation.