What is cardiac arrhythmia?

Most healthy adults have a resting heart rate between 60 and 100 beats per minute. Arrhythmia is when the heartbeat is irregular – too fast, too slow, or out of time. Arrhythmia comes in many forms, some of which include:

  • Bradycardia – a slow resting heart rate (less than 60 bpm)
  • Tachycardia – a fast resting heart rate (over 100 bpm)
  • Fibrillation/flutter – a rapid, uncoordinated heart rate
  • Premature contraction – extra heartbeats that occur one at a time

Prof. Dion Stub is a leading interventional cardiologist that provides arrhythmia diagnosis and management from locations across Melbourne.

Causes & risks

Factors such as age, lifestyle, and family history can impact your chances of developing cardiac arrhythmia. Some medications (including some cold and flu medications), previous heart injury (such as scarring from a previous heart surgery), and alcohol and drug use may also trigger it. Some studies suggest that men may have a higher risk.

Symptoms of arrhythmia

  • A fluttering sensation in the chest
  • Heart palpitations (being uncomfortably aware that your heart is beating)
  • Dizziness and/or fainting
  • Light-headedness
  • Weakness
  • Breathlessness

Some arrhythmias don’t cause symptoms at all and may remain undetected until your GP notices it during a check-up.

Why is cardiac arrhythmia dangerous?

Arrhythmia means that the heart is not pumping effectively. While most arrhythmias aren’t life-threatening on their own, they can contribute to more dangerous conditions.

Ineffective pumping can contribute to blood clots forming, which may dislodge and cause a stroke or pulmonary embolism. Atrial fibrillation in particular is a common cause of this.

Prolonged arrhythmia can also cause the heart to lose its ability to pump blood effectively, leading to heart failure.


Your cardiologist needs to identify the irregular rhythm and find its source or trigger. Prof. Dion Stub can organise the appropriate tests and diagnostics to assist in diagnosis of arrhythmia.

Tests used for diagnosing cardiac arrhythmia may include:

  • ECG – this is the most common and most effective way to diagnose arrhythmia. It measures your heart’s electrical signals and records any abnormalities.
  • Exercise ECG – similar to a regular ECG test, but performed while you are exercising (usually on a treadmill). It allows the cardiologist to see how your heart responds to stress.
  • Holter monitor – this may be recommended if a standard ECG cannot detect the arrhythmia accurately. It is worn over 1-3 days and records your heart’s electrical signals periodically, showing how your heart behaves throughout the day.
  • Cardiac event recorder – this battery-powered device records your heart’s activity over weeks or months. You will need to carry a small remote and press a button when you have symptoms, which will signal the device to record it.
  • Echocardiogram – an ultrasound of the heart, which your cardiologist may use to check your heart’s rhythm and the passage of blood through it.
  • Electrophysiological (EP) study – a minimally invasive procedure done in a hospital, in which a team of specialised cardiologists introduce catheters to your heart via blood vessels. These can map the heart or be used to introduce medications and monitor your heart’s response.

Arrhythmia treatments

Arrhythmias are not always life-threatening and may not require treatment. If treatment is required, Prof. Dion Stub will always thoroughly assess your condition and ensure you are fully informed before starting any.

Treatment options may include:

  • Medications – a wide range of heart medications can be prescribed to treat arrhythmia based on its underlying cause. Prof. Dion Stub may prescribe anticoagulants, beta-blockers, or other suitable medications.
  • Lifestyle changes – Prof. Stub will work with you to identify arrhythmia triggers and manage them. Staying physically active and maintaining a healthy diet can help reduce your symptoms and risk of complications.
  • Cardioversion – this involves administering an electric shock to your chest under general anaesthesia to restore normal heart rhythm. Cardioversion is usually performed as an outpatient procedure and may be recommended if medication has not been effective.
  • Pacemaker/ICD – these devices are implanted in the chest to monitor your heart rhythm and correct it with electrical stimulation if needed. They are usually recommended after other treatments have faied and may be used in conjunction with other therapies.

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