Arrhythmia

Introduction

Heart arrhythmia - the cause of that fluttering feeling - is often nothing more than a blip in your heart's rhythm. Many people feel a flutter or skipped beat, from time to time, and these are usually nothing to worry about. But for some people, arrhythmia can be a sign of something more serious, such as a heart condition, or damage following a heart attack, so it's important to get those flutters checked out.

What is arrhythmia?

You may have heard the heartdescribed as a pump, which keeps blood circulating around your body. Electrical impulses keep your heartpumping at a regular rate.

The hearthas four chambers that pump blood. The two at the top are called the atria. The two lower chambers are the ventricles. The electrical impulses come from a bundle of nerves called the sinus node located in your right atrium. This node is your heart's natural pacemaker and keeps it beating normally.

If the normal, steady delivery of these impulses changes and becomes irregular, it can cause arrhythmia, where the heartbeats faster or slower than normal, or beats irregularly, interfering with its ability to pump blood effectively.

Supraventricular arrhythmias, or arrhythmias which occur in top part of your heart, include atrial fibrillation (AF), atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and Wolff-Parkinson-White (WPW) syndrome. Arrhythmias can also happen in the bottom part of the heart. Both types of arrhythmias should be investigated by your doctor, as they can be very dangerous to your health.

 What are the symptoms of arrhythmia?

You don't always get symptoms with an arrhythmia. It may be something that your GP picks up during a check-up for something else.

If you do feel symptoms they can include either a fast or a slow heartbeat, fluttering in your chest, chest pain, feeling short of breath, light-headed or dizzy, or even fainting. If you have these symptoms, you should see your GP.

Are there different types of arrhythmia?

• Sinus Tachycardia:this type of arrhythmia means that your heart is beating too fast - usually at more than 100 beats a minute. The normal rate for an adult heart is 60-100 beats per minute, although this increases when you exercise
• Sinus Bradycardia:this type of arrhythmia means that your heart beats more slowly than normal (under 60 beats a minute)
• Ectopic heartbeats:these are extra heartbeats. Most people have one, at least, every 24 hours. People with a heart condition are more likely to have them. These extra heart beats are normal, and aren't generally dangerous

What causes arrhythmia?

This varies depending on the type of arrhythmia you have. A range of different conditions can cause arrhythmia, including ischaemic and heart valve disease, high blood pressure and other heartdisorders. However, doctors aren't always able to find a specific cause.

Often tachycardia that comes on gradually occurs due to natural everyday events, such as exercise, excitement or other emotions. Stress and stimulants, such as caffeine, alcohol and cigarettes can also cause tachycardia. A high fever and anaemia can also be a cause, as can an overactive thyroid gland.

Some prescription drugs, including asthma medicine, cough and cold remedies and diet pills can cause arrhythmia, so be sure to tell your doctor about any medicines you've been taking.

Anirregular tachycardia, where the heart's rhythm is erratic, can be a result of a condition known as atrial fibrillation. It occurs when the heart's atria, the upper chambers, are beating irregularly, and often faster than normal.

Atrial fibrillation can increase your risk of blood clots and, as a result, stroke. Your doctor may feel that you need treatment with anticoagulants, to reduce the likelihood of blood clots forming.

A number of different conditions can cause bradycardia:

• Sick sinus syndrome:when your heart's pacemaker (sinus node) isn't working properly
• Syncope:when you lose consciousness, or faint (a symptom of bradycardia)
• Heart block:when the passage of electrical impulses through your heart is interrupted or blocked

There are a number of tests to check for arrhythmia:

• Electrocardiogram (ECG):This test shows your doctor how your heart is beating, and whether you have any irregularities in your heartrhythm
• ECG/Holter monitor:If your doctor wants to monitor and record your heart rhythm for a longer time - from 24 hours to seven days - you may be asked to wear a Holter monitor. It's a small device that you wear around your waist, and has three or four electrodes that will be attached to your chest with sticky pads
• Cardiac Event Monitor (CEM):Also used for longer periods of monitoring, the cardiac event monitor is worn around your neck and has two leads that are attached to your chest. This device monitors your heart rhythm all the time it's on. You'll be asked to press a button whenever you notice any symptoms, this will store the recording

These tests are useful, because their results give your doctors information about your heartbeat and rhythm - whether it's regular or irregular. This will help them make an accurate diagnosis.

Other options to help diagnose arrhythmia include:

• Implantable loop recorder, which is fitted under your skin, on your chest, and records your heart's electrical activity
• Electrophysiological study where fine electrode catheters are fed through a vein and then into your heart. They can then trigger palpitations and then stop them, which also helps find the cause of the problem.

What is the treatment for arrhythmia?

You may not need any treatment, especially for tachycardia that happens normally and doesn't pose a risk to your health. Your doctor will talk to you about the treatments available, and suggest the most suitable for you.

Advice may include being aware of what sets off your arrhythmia, and steering clear of those causes, or teaching you how to stop arrhythmia once it has started. You may be also be prescribed medication (anti-arrhythmic drugs) or electric shock treatment under sedation.

These are some of the other treatments available:

• Surgical treatment: your doctor may feel that surgery is the most suitable treatment in your case
• Catheter Ablation: usually carried out under local anaesthetic for atrial fibrillation, often with a sedative to make you feel relaxed. Wires (catheters) are passed through fine tubes into an incision, usually at the top of your leg. From there, they travel through your blood vessels to your heart. Using heat, or cryo-therapy (extreme cold), the doctor will ablate (destroy), the cells that are causing the electrical disturbance and the atrial fibrillation. In most cases, catheter ablation cures arrhythmia, although a few people may need to have this carried out more than once
• Implantable Cardioverter Defibrillator (ICD): may be used in cases where unstable rhythms are life-threatening. It is implanted under the skin, and a wire is fed from the device to the interior of the heart. It can sense - and stop - abnormal rhythms by giving the heart a brief electric shock
• Cardioversion: carried out under general anaesthetic. Cardioversion is aims to convert an arrhythmia back to normal sinus rhythm. Electrical cardioversion is used when the patient has a pulse but is unstable or has not responded to chemical cardioversion
• Pacemaker: if you have bradycardia, your doctor may recommend you have a pacemaker fitted. This small device is fitted under your skin near your collarbone, with leads that attach to your heart. When it detects that your heartbeat is too slow, it sends an electrical impulse to speed it up to a normal rate. Pacemakers are also used to treat atrial fibrillation

 Questions to ask your doctor

• What kind of arrhythmia do I have?
• How will this affect my health?
• What tests do I need to have?
• What treatment is available to me?
• Will the treatment cure the arrhythmia?

Clickthrough information and support links:

Arrhythmia Alliance
British Heart Foundation