Arrhythmia: Types, testing and diagnosis« Back to Articles
Arrhythmia occurs as the result of a fault in the heart’s electrical system. This then affects the heart’s pumping rhythm, causing it to beat irregularly, too fast, or too slow. Many patients report they can feel a ‘thumping’ in their chest although this may not always be the case.
Most arrhythmias are not serious or a threat to life, but they will need to be managed correctly.
What are the various types of arrhythmias?
“Arrhythmia” is an umbrella term that covers a spectrum of electrical system problems which control the heart’s pumping rhythm. The type of arrhythmia depends on whether it’s located in the atria or ventricles. They’re also classified by the speed of heart rate they cause slow heartbeat (bradycardia), fast heartbeat (tachycardia) or irregular heartbeat. Here are the main types of heart arrhythmia to be aware of:
Abnormal electrical activity in the heart’s top chambers overwhelms the heart’s electrical system, causing signals to become chaotic. The heart’s top two chambers (atria) twitch instead of properly contracting. The atria then beat too fast and out of rhythm with the heart’s lower two chambers (ventricles).
Atrial flutter is similar to atrial fibrillation. The main difference however is that with atrial flutter the heart rhythm is less irregular and chaotic than the abnormal rhythm in atrial fibrillation. Sometimes an atrial flutter can develop into atrial fibrillation and vice versa.
This one can frequently affect otherwise healthy individuals. It’s where the heart either adds a beat or misses one. Ectopic beats can occur in the bottom (ventricle) or top (atria), or in the heart chambers.
Paroxysmal arrhythmias start and stop suddenly. Episodes can go on for just a few seconds, minutes or hours, but they may sometimes last up to a week. Generally, this type of arrhythmia will have a particular trigger such as over-exercising.
Heart block (atrioventricular heart block and bundle branch block)
Heart block (also referred to as atrioventricular (AV) heart block and bundle branch block) is where there’s a delay in the heart’s electrical messages possibly due to a blockage. This can cause the heart to pump in an abnormal way, often slowing down to under 60 beats per minute.
Long QT syndrome, Brugada syndrome and Wolff-Parkinson-White (WPW) syndrome
These different conditions can all bring about fast and irregular heartbeats. They are related to a particular abnormality in the heart electrical system that can lead to fainting spells or even cardiac arrest.
Supraventricular tachycardia (SVT)
These are a group of arrhythmias caused by abnormal electrical activity in the heart’s atria. They are characterised by the heart suddenly beating very quickly, often over 100 beats per minute.
Tachybrady syndrome (sick sinus syndrome)
This type of arrhythmia is due to a problem with a part of the heart’s electrical system called the sinus node. It causes the heart rate to vary from extremely fast to extremely slow.
This arrhythmia is caused by abnormal electrical activity in the heart’s ventricles. This causes a fast heartbeat that can start very quickly and last for seconds or go on for longer. If it continues, it must be treated as soon as possible due to the risk of cardiac arrest.
Ventricular fibrillation is caused by abnormal electrical activity in the heart’s ventricles that causes a very fast, erratic and ineffective pumping rhythm. This is a medical emergency is it often leads to cardiac arrest.
If you suspect an arrhythmia, you’ll need to carry out a full physical examination and patient history. You may well also need to refer the patient for the following diagnostic tests in order to confirm arrhythmia or rule out other conditions:
Electrocardiogram (ECG) – To measure the heart’s electrical signals, as well as the timing and duration of each electrical phase in the patient’s heartbeat.
Holter monitor – A portable ECG that records the heart's activity for period of at least 24 hours.
Event recorder – Another type of portable ECG that records the heart's activity over a period of weeks or months.
Echocardiogram – This test generates moving images of the heart and can assist in diagnosing blood clots and structural heart disease.
Implantable loop recorder – An implantable loop recorder can be implanted in the patient’s chest under the skin. It continuously records the heart's electrical activity and detects abnormal heart rhythms.
Stress test (exercise testing) – This test measures arrhythmias triggered by exercise.
Tilt table test – The Tilt table test monitors the patient’s heart rate and blood pressure as they lie flat on a table. It also examines how the heart responds when the patient stands up.
Electrophysiological testing and mapping – In this test, electrodes can map the spread of electrical impulses through the patient’s heart. Electrodes are then used to stimulate the heart to trigger an arrhythmia.
Could you accurately diagnose an arrhythmia?
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