Sometimes palpitations or an irregular heart beat can be symptoms of a group of conditions known as arrhythmias.
"Arrhythmia is an umbrella term for a heart rhythm that is either faster, slower or more irregular than the normal heart rhythm”
Tachycardia is a faster than normal heart rate, whereas bradycardia is an abnormally slow heart rate. There is also a form of arrhythmia called ectopy, which are “extra beats” often triggered by stress, caffeine intake or an overactive thyroid.
“The slow heart rhythms, the bradycardias, are more common with increasing age but also as side effects from some heart medications,” Dr Ellims says.
Supraventricular tachycardia (SVT) is caused by “abnormal wiring” of the heart’s electrical circuit and commonly occurs in young people, with a rapid onset of fast palpitations often accompanied by dizziness.
Ventricular tachycardia (VT) is a regular, fast heart rate caused by abnormal electrical signals in the “pumping” chambers of the heart.
“VT usually occurs in someone who has an abnormal heart, whether they have had a previous heart attack or an inherited heart disease, called cardiomyopathy,” Dr Ellims says.
Another form of arrhythmia is atrial fibrillation (AF), in which the “collecting” chambers of the heart quiver rather than beat normally. Dr Ellims explains that AF is associated with an increased risk of stroke.
“The prevalence of AF increases as we get older but can also occur in the context of abnormal heart structure, like leaky or narrowed valves. It can also occur with binges of alcohol,” he says.
How are arrhythmias diagnosed?
“Patients who are experiencing unexplained dizziness or palpitations should see their GP to investigate it further.” - Dr Andris Ellims, Cardiologist, Epworth HealthCare
Dr Ellims explains that a key aspect of diagnosis of arrhythmia is to obtain a recording of the heart rhythm at the time of symptoms, usually with a 24-hour Holter monitor.
“The chances of experiencing symptoms in a 24-hour period are minimal, so in recent years there have been new ways of increasing the chance of catching an arrhythmia,” he says.
New devices include an implantable loop recorder, dubbed the “three-year black box” by Dr Ellims, which records the heart’s electrical rhythms and wirelessly uploads the data to the cardiologist. Another involves patients placing their fingers on a credit-card sized pad, paired to their smartphone, to create an electrical trace when they experience symptoms. Some smartwatches currently on the market can also detect some forms of arrhythmia but are usually limited to atrial fibrillation.
“On the horizon, the new generations of smartwatches will likely increase the chance of recording symptomatic arrhythmias. Increasingly, we will also need to manage incidental arrhythmias that people haven’t really felt but have been picked up on their monitor,” Dr Ellims says.
How is arrhythmia treated?
Lifestyle adjustments can help patients with arrhythmia, such as good sleep patterns, a balanced diet, regular exercise, managing psychological stress and moderating alcohol and caffeine intake.
Some patients may require medication or an implanted cardiac device such as a pacemaker or defibrillator to assist the heart to keep a regular, healthy rhythm. Some arrhythmias, such as SVTs, can be treated with an ablation, which is a “microburn” inside the heart to neutralise abnormal electrical circuits within the heart.
Many patients with arrhythmia should also have their blood thinned to prevent stroke risk. Dr Ellims says new drugs have superseded warfarin but are still underutilised.
“There are still patients with stroke-associated arrhythmias such as atrial fibrillation who should be on blood thinners but, for a variety of reasons, are not. Patients should proactively ask their doctors about their stroke risk.”
01 November 2019