10 July 2017

What is an arrhythmia?

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Arrhythmia is an abnormal heart rhythm caused by problems in the heart’s electrical system. Any change in the normal sequence of electrical impulses, which may feel like your heart is racing, thumping or skipping beats, is considered as arrhythmia.

Arrhythmias are quite common, especially as you get older. Most cases are harmless, but some arrhythmias are extremely dangerous and require treatment. When your heart doesn’t beat properly, it cannot pump blood effectively, so the lungs, brain and all other organs can’t work well and may get damaged or even shut down. Therefore, it’s important to see a doctor or health practitioner to find out the cause and the type of arrhythmia.

They are usually classified by an origin site: atria or ventricles; or by a heartbeat they cause:

  • Tachycardia – a fast heartbeat greater than 100 beats per minute.
  • Bradycardia – a slow heartbeat less than 60 beats per minute. Not all tachycardias or bradycardias mean you have a heart disease. It’s normal to develop a fast heartbeat during the exercise, or slower one during the sleep or relaxation.
Sinus tachycardia with 160 bpm heart rate
Sinus tachycardia with 160 bpm heart rate

Supraventricular Arrhythmias

Supraventricular arrhythmias are tachycardias that start in the atria, the heart’s top chamber, or atrioventricular (AV) node. These arrhythmias are not responsible for dramatic events such as sudden cardiac death, but the most common one, atrial fibrillation, can lead to fatal strokes. There are four main types: atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia and Wolff-Parkinson-White syndrome. Most of them have a narrow QRS complex.

Ventricular arrhythmias

Ventricular arrhythmias start in the heart’s lower chambers, the ventricles. Considering that the ventricles are the heart’s main pumping chambers, the majority of the potentially lethal arrhythmias are ventricular in origin and usually require medical care right away. They may be caused by coronary heart disease, heart attack or weakened heart muscle; and almost always have a wide QRS complex. They include ventricular tachycardia and ventricular fibrillation, which is a cause of cardiac arrest and sudden cardiac death.

Sinus bradycardia with 40 bpm heart rate.
Sinus bradycardia with 40 bpm heart rate.


Bradycardia is a low resting heat rate and it doesn’t always signal a problem. If you’re physically fit, your heart can pump adequate blood supply with less than 60 bpm at rest. Also, if you use certain medications to treat other conditions, like high blood pressure drugs, they may lower your heart rate. However, if your heart isn’t pumping enough blood, you may have one of bradyarrhythmias, including: sick sinus syndrome and heart block. Bradycardia is treated by discontinuing any medication that slows down the heartbeat, treating any underlying condition and/or by implanting a permanent pacemaker.

Premature heartbeats

Premature heartbeats are the most common type of arrhythmia and may feel like chest fluttering or skipped heartbeats, but they are actually an extra beats. They are usually caused by stress, too much exercise or stimulants like caffeine or nicotine.

Basically, if you have bradycardia, you may feel tired, short of breath, dizzy or faint. And if you have tachycardia, your heartbeat might feel like a strong pulse in your neck or a fluttering, racing beat in your chest. Also, you can feel discomfort in your chest, weakness, shortness of breath, faint, sweaty or dizzy. So, if you have any of these symptoms, see your doctor immediately. It is important to start treatment on time.

Sources: http://www.mayoclinic.org/diseases-conditions/heart-arrhythmia/symptoms-causes/dxc-20188128 https://www.nhlbi.nih.gov/health/health-topics/topics/arr/types http://www.texasheart.org/HIC/Topics/Cond/arrhycat.cfm