About abnormal heart rhythms
Your heart is a muscle that pumps blood, oxygen and important nutrients to all parts of your body.
Normally, the pumping action of your heart (your heartbeat) is controlled by your heart’s electrical system. In a healthy heart, regular electrical signals cause the heart to contract and relax in a steady rhythm of 60 to 100 beats per minute.
Sometimes, your heart’s electrical system may not work properly because of heart disease, some medicines, or sometimes for no known reason. Changes in your heart’s electrical system can cause abnormal heart rhythms, also called ‘arrhythmias’.
Palpitations are a sensation or awareness of your heart beating. It may feel like your heart is racing, thumping, fluttering, pounding or skipping beats. Almost everyone has palpitations at some time in their life.
Palpitations may have no obvious cause, but can be triggered by:
- physical activity
- emotional stress
- stopping some medicines
- illicit substances.
An occasional palpitation that does not affect your general health is not usually something to worry about. See your doctor if you have more frequent or consistent palpitations, which may be associated with a serious abnormal heart rhythm.
Types of abnormal heart rhythms
There are many kinds of abnormal heart rhythms. Some may cause your heart to skip or add a beat now and again but will usually have no effect on your health or ability to lead a normal life. Other abnormal rhythms are more serious and can be life-threatening if left untreated.
Abnormal rhythms are classified by their rate and rhythm: fast heartbeat (tachycardia), slow heartbeat (bradycardia) or irregular heartbeat.
Tachycardia is when your heart beats too fast, generally more than 100 beats per minute. Some forms of tachycardia are easily treated and not serious, but others can be life-threatening.
The two main types of tachycardia are supraventricular tachycardia (problem with the upper chambers of the heart) and ventricular tachycardia (problem with the lower chambers).
Supraventricular tachycardia is not usually life-threatening. Common types of supraventricular tachycardia are atrial flutter and atrial fibrillation.
Ventricular tachycardia happens when the ventricles (the lower chambers) beat too fast, and it’s very dangerous. If ventricular tachycardia becomes so severe that the ventricles can’t pump effectively, it can lead to ventricular fibrillation. This life-threatening condition occurs when the electrical signal that should trigger your heartbeat behaves erratically. It must be corrected immediately, otherwise it may cause low blood pressure, loss of consciousness and even death.
Bradycardia is when your heart beats too slowly, generally less than 60 beats per minute. It becomes serious when your heart beats so slowly that it can’t pump enough blood to meet your body’s needs.
Bradycardia may be normal for you, and some people who do a lot of exercise and are physically fit can have a slower heart rate. However, it can also be caused by heart disorders, such as sick sinus syndrome and heart block.
‘Sick sinus syndrome’ occurs when the natural pacemaker (sinus node) in your heart malfunctions and ‘fires’ too slowly, telling your heart to beat slowly. It can also cause heartbeats that are too fast or heartbeats that alternate between slow and fast.
‘Heart block’ is when there is a block or delay in the electrical signal from your heart’s upper chambers (atria) to its lower chambers (ventricles). It often results from damage to your heart’s electrical pathways. Types of heart block include atrioventricular heart block and bundle branch block.
Other types of abnormal heart rhythms
- Ectopic heartbeats occur when your heart misses a beat or adds an extra beat. They can arise from the atria or ventricles.
- Long QT syndrome, Brugada syndrome and Wolff-Parkinson-White (WPW) syndrome can cause fast and irregular heartbeats. These conditions are related to a specific abnormality in the heart’s electrical system that can lead to fainting or even cardiac arrest.
- Paroxysmal arrhythmias are when the abnormal rhythm starts and stops suddenly. Episodes of paroxysmal arrhythmia can last for seconds, minutes, hours or up to a week.
Symptoms of abnormal heart rhythms
Occasional palpitations during periods of emotional or physical stress are normal and are nothing to worry about. However, an irregular heartbeat can be a sign of an abnormal heart rhythm, or another heart condition. Talk to your doctor if you feel your heart beating too fast, too slowly or irregularly.
Symptoms of an abnormal heart rhythm can include:
- palpitations (a feeling of your heart racing, thumping, fluttering, pounding or skipping beats)
- light-headedness or dizziness
- shortness of breath
- chest pain
Immediately call Triple Zero (000) and ask for an ambulance if along with palpitations, you start to feel any of these warning signs:
- pain or discomfort (pressure, heaviness or tightness) in your chest, neck, jaw, arms, back or shoulders
- you feel nauseous, you’re having a cold sweat, you feel dizzy or are short of breath, and you feel this way for more than 10 minutes.
Causes of abnormal heart rhythms
There are some conditions that can lead to an abnormal heart rhythm, including:
- a heart attack
- congenital heart disease
- coronary heart disease
- heart failure
- high blood pressure
- obstructive sleep apnoea
- structural heart abnormalities – such as from cardiomyopathy, heart valve disease or scarring from a previous heart attack
- thyroid problems
- excess alcohol intake.
Abnormal heart rhythm triggers
Other common triggers of an abnormal heart rhythm include:
- nicotine (either in cigarettes or e-cigarettes)
- other unrelated illness such as a cold or flu
- recreational drugs
- some medicines (over-the-counter or prescription)
- stress (physical or emotional)
Talk to your doctor if you think your medicine is triggering an abnormal rhythm. Never stop taking prescription medicine without talking to your doctor or pharmacist first.
In some people, certain types of exercise may trigger an abnormal heart rhythm. If you think this is happening to you, talk to your doctor. Physical activity is very important for your heart health and overall wellbeing and should not be avoided without talking to your doctor first.
Diagnosing abnormal heart rhythms
If you experience any symptoms of an abnormal heart rhythm, including palpitations, see your doctor. Ways of diagnosing heart failure include:
- physical examination including listening to the heart with a stethoscope and checking your heart rate
- blood tests
- electrocardiogram (ECG) – records a detailed snapshot of your heart rate and rhythm. You may have this done while you are resting or exercising (for example, on a treadmill), or have a portable ECG recorder attached to you for a longer period of time (for example 24 hours)
- echocardiogram (ultrasound scan of the heart)– helps your doctor check if there are any problems with your heart’s valves and chambers, and see how strongly your heart pumps blood
- electrophysiology studies – a catheter is inserted into your body and directed to your heart while you are sedated. It records your heart’s electrical activity and response to certain triggers
- tilt test – to find out if different body positions trigger the abnormal heart rhythm.
Treatment for abnormal heart rhythms
Treatment for an abnormal rhythm depends on its cause and how much it’s affecting your health and lifestyle. It’s important to remember that not all abnormal rhythms are dangerous or life-threatening.
Treatments for abnormal heart rhythms include:
- medicines – to stabilise the heart rhythm, or treat conditions that are causing the abnormal heart rhythm
- electrical cardioversion – a mild electrical current that restores a normal heart rhythm. Electrical cardioversion is usually a planned procedure given under sedation.
- catheter ablation – a catheter with an electrode on the end is inserted into your body and directed to your heart, where it gently disrupts or deactivates the area of the heart where the abnormal electrical signals are coming from
- implantable cardioverter defibrillator – a device to monitor and correct your heart rhythm if it’s dangerous
- pacemaker – a small electronic device that electrically stimulates the heart to maintain a regular heart rhythm
- surgery – to remove or inactivate the malfunctioning area(s) of the heart
- defibrillation – use of a mild electrical current to ‘reset’ your heart rhythm. Defibrillation is usually given in an emergency situation.
Living with an abnormal heart rhythm
If you’ve been diagnosed with an abnormal heart rhythm, you may wonder how serious your condition is and what it means for the future.
It's also normal to experience a range of emotions such as fear, uncertainty, anxiety and low mood. If you are worried about your thoughts or how you are feeling, talk to your doctor and seek support from your loved ones.
To help manage your condition:
- identify your abnormal heart rhythm triggers
- take your medicines as prescribed
- make healthy lifestyle changes – including managing stress, quitting smoking, drinking less alcohol, following a heart-healthy eating pattern and staying active
- manage blood pressure and cholesterol levels
- maintain a healthy body weight.
Where to get help
- In an emergency, always call triple zero (000)
- Your GP (doctor)
- Heart Foundation
- Emergency department of your nearest hospital
- NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice 24 hours a day, 7 days a week