You always know a medical condition is important when it's known by its initials - and every doctor knows all about AF, or atrial fibrillation. It affects over a million people in the UK, with 50,000 people diagnosed every year.
How common is AF?
When I was a medical student, AF was a bit of a medical rarity. But as we live longer and longer, it's getting more and more common. About one in 200 people in their 50s has AF, compared to one in 10 of over-80s. It's the most common cause of irregular heart rhythm in the UK, and along with age, other causes include high blood pressure , heart disease and overactive thyroid gland.
AF symptoms, which can come on suddenly, include an irregular heartbeat with no pattern to it; breathlessness on exercise; dizziness; and sometimes chest pain. These happen because the different parts of heart muscle aren't able to co-ordinate, so contractions are less efficient at pushing blood round the body. But about one in five people with AF have no symptoms at all, and it's picked up by accident when your doctor or nurse examines you. Keeping your blood pressure under control can cut your risk of developing AF - get it checked regularly.
How is AF diagnosed?
If your doctor thinks you might have AF, they'll send you for a tracing of your heart called an ECG. Sometimes AF comes and goes over minutes or hours, and you may be asked to wear a heart monitor for 24 hours to pick up bouts of AF. You'll also have a painless scan called an echocardiogram, and sometimes blood tests.
It's very important to get atrial fibrillation diagnosed and treated, even if you don't know you've got it. That's because if you don't have the right treatment, you're about five times more likely to have a stroke if you have AF. Fortunately, taking regular tablets to reduce the tendency of your blood to clot can hugely reduce that risk. Check your pulse - if it's completely erratic, with no regular rhythm at all, you could have AF.
AF - how can you cut your risk of stroke?
In the past, many people were put onto a regular low dose (75mg) aspirin tablet every day. In fact, we now know that this doesn't cut your risk of stroke by very much in AF. What's more, it can cause side effects like bleeding from the stomach. That's why it's no longer recommended for AF. It's important to know that even though aspirin hasn't proved that good for AF, it's extremely effective at preventing another heart attack or stroke if you've already had one. So if you're taking regular aspirin, don't stop it without your doctor's advice.
The most commonly recommended medicine to prevent strokes in AF today is the blood-thinning medicine, warfarin. It cuts your risk of stroke by nearly 60%. You need to have regular blood tests to monitor a clotting level called INR, which can be done with a fingerprick. People who aren't on treatment have an INR around 1. If you have AF, the aim will usually be to keep your INR between 2 and 3. If it's lower than this, you're at increased risk of a stroke; if it's higher, you're at increased risk of bleeding, including bleeding into your brain.
Because lots of things can interfere with how your warfarin works, your dosage may have to be adjusted when you have your test. Cabbage, spinach and broccoli, alcohol, cranberry and grapefruit can all upset your warfarin levels. So can other medicines including some herbal remedies, so always check with your pharmacist.
The 'new generation' of blood-thinning agents are called the NOACs or DOACs apixaban, dabigatran, exoxaban and rivaroxaban. You don't need the same blood monitoring, you don't need to change the dosage and they don't interact with food or other medicines in the same way. They aren't for everyone, but they are just as effective as warfarin and they may be an option if your warfarin levels are hard to control. The National Institute for Health and Care Excellence (NICE) recommends that doctors should consider switching you to a NOAC if you're on warfarin for six months and during that time:
- You have 2 INR levels above 5 or under 1.5
- You have one INR level above 8
- On average, fewer than 65% of your readings are in range.
AF - rate or rhythm?
If your AF is causing symptoms, you may be treated with regular medicines to slow your heart rate down or make it regular. In the past, rhythm control - getting your heart back into a regular rhythm - was thought to be safer than simply controlling the rate. However, more recent evidence suggests long-term outcomes are just as good with rate control, and the drugs used to achieve this are more reliable and often have fewer side effects.
So rhythm control is now only considered as a preferred option in the UK if you have a reversible cause, such as overactive thyroid (in which case treating the underlying problem should get your heart back into a normal rhythm); if your AF has only just started, especially if you're under 65; or if you have heart failure thought to be due to your AF.
What are the rate-controlling drugs for AF?
The first choice treatments to slow your heart down to a normal rate arebeta-blockers. Digoxin used to be widely used, but doesn't perform as well as beta blockers in active people. However, it or a calcium-channel blocker such as verapamil might be used as an add-on to beta blockers, or as an alternative if there's a medical reason you can't use beta blockers.
People who get occasional symptoms may be offered a 'pill in the pocket' to take when a bout comes on. Depending on your circumstances, you may be offered treatment with an electric shock, called cardioversion, to bring your heart back to its normal rhythm. Another procedure called catheter ablation, which aims to destroy small parts of the heart muscle which are triggering your atrial fibrillation, is considered in some cases too.
With thanks to 'My Weekly' magazine where this article was originally published.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Egton Medical Information Systems Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.