Arrhythmias (abnormal heart rhythms)

Arrhythmias can happen when your heart's electrical system breaks down or malfunctions. This may be a symptom of underlying coronary heart disease or other medical problems.

Irritable heart cells

Sometimes cells within your heart will malfunction and send out electrical signals when they shouldn't. Signals from these cells interfere with the proper signals from your heart's natural pacemaker and confuse your heart, making it beat irregularly.

Blocked signals

If the electrical signal that makes your heart beat becomes blocked, the signal may not reach the main pumping chambers of your heart (the ventricles). This makes your heart beat very slowly (bradycardia).

Abnormal pathway

Sometimes your heart's electrical signal might start at the right place and time, but get interrupted, misdirected and not follow its normal path. This can cause an arrhythmia.

Medicines and stimulants

Certain medicines and stimulants, such as caffeine and nicotine, can make your heartbeat abnormal.

Coronary artery spasm (Prinzmetal angina)

Severe or prolonged coronary artery spasm (which generally causes chest pain or angina) can also cause arrhythmias.

Your doctor may use one or more of the below tests to diagnose arrhythmias.

Electrocardiography (ECG)

Electrocardiography (ECG) shows your doctor how the electrical system in your heart is working.

During an ECG test, electrical leads are placed on your chest, arms and legs. These leads detect small electrical signals and produce a tracing on graph paper that illustrates the electrical impulses travelling through your heart muscle.

ECGs can be performed in several different ways, including:

• resting ECG – performed with you lying still and quiet; it lasts only a few minutes
• Holter ECG – a Holter monitor (portable ECG machine) records heart activity continuously as you go about your daily activities, usually over a 24-hour period
• stress ECG (also known as 'exercise’ ECG or 'stress test') – usually performed while you are exercising on an exercise bike or treadmill.

Tilt tests

Tilt tests can help doctors to know whether or not different body positions will trigger an arrhythmia. They are especially useful for investigating the hearts of people who faint without explanation.

Electrophysiology studies

Electrophysiology studies may be done to find out more about an abnormal heartbeat.

During an electrophysiology study, special catheters are inserted, via a vein in your leg, into your heart. The catheters record your heart's electrical activity and test its response to various stimuli.

Your heart's electrical response to these stimuli helps doctors to determine the type and cause of your arrhythmia.

Treatments for arrhythmias can vary depending on the cause and the extent to which your health or lifestyle is affected.

Appropriate treatments can include simple lifestyle modifications, medicines, implantable medical devices and surgical or other procedures.

Medicines

Several medicines are available that slow down a very fast heartbeat (tachycardia), including anti-arrhythmic medicine and beta-blockers. They may be used for short or long term.

Medicines may also be used to treat other types of arrhythmias.

Artificial pacemakers

Artificial pacemakers are usually given to people with a slow heartbeat (bradycardia).

Like a normal heart's electrical system, an artificial pacemaker uses small electrical currents to stimulate your heart muscle and make it pump regularly.

Implantable cardiac defibrillators (ICDs)

Implantable cardiac defibrillators (ICDs) are small devices that can be put into your chest and connected to your heart to monitor and correct your heartbeat. They are sometimes given to people who are at risk of dangerous heart arrhythmias.

Cardioversion

Cardioversion may be used to return the heart to a normal rhythm if you have a long or serious episode of atrial fibrillation.

In electrical cardioversion, your heart is given an electrical shock (while you are under an anaesthetic) to help restore a normal heart rhythm and reduce long term risks associated with atrial fibrillation.

In pharmacological cardioversion, medicines are used to return your heart to a normal rhythm.

Catheter ablation

In catheter ablation procedures, a long, thin tube (catheter) is inserted into a blood vessel in the leg and threaded through the vessel until the tip reaches the heart. At the tip of the catheter is an electrode, which can emit radiofrequency waves to burn and inactivate the area(s) of the heart responsible for creating or passing abnormal signals.

Surgery

In some cases, arrhythmias can be treated by surgically removing the sections of the heart muscle that are malfunctioning. Although not commonly used, surgery can be very effective in treating some arrhythmias.

Arrhythmias are often associated with other forms of cardiovascular disease, and it is important to manage the risk factors for these conditions.

To reduce your risk of more heart problems you should:

• take your medicines as prescribed
• be smoke-free
• enjoy healthy eating
• be physically active
• control your blood pressure and cholesterol
• achieve and maintain a healthy body weight
• maintain your psychological and social health
• maintain blood glucose levels if you have diabetes.