What is an arrhythmia?

Arrhythmia is an umbrella term to describe a number of conditions where the muscle contraction of the heart is too slow, too fast or irregular because of a disturbance in the heart’s normal electrical activity.

Most arrhythmias just occur with no obvious cause. They can be due to genetic disorders or an acquired condition. Arrhythmias can range in severity from a minor inconvenience or discomfort to a potentially fatal problem. Atrial fibrillation is the most common form of sustained arrhythmia and can cause considerable disability and predispose a person to stroke.

Types of arrhythmia

There are two basic types of arrhythmia, with variations of each:

Bradycardia - a heart rate that is too slow, usually less than 60 beats per minute
Tachycardia - a heart rate that is too fast, usually more than 100 beats per minute


  • Atrial fibrillation
    • Ths is the most common, serious, abnormal heart rhythm involving rapid and irregular activity in the chambers of the heart
    • Although it may affect young people, it becomes more common with increasing age, and typically affects older patients of 65 and over. It affects men and women equally
    • Atrial fibrillation is a common cause of stroke. The overall incidence of stroke is approximately 5% per year in people with atrial fibrillation
    • It is the most common cause of hospital admissions for arrhythmias
  • Ectopic beats
    • These are heart beats which occur earlier than normal within the normal heart cycle
    • Ectopic beats can come from either the atria (the two top chambers of the heart) or the ventricles (the two lower chambers of the heart)
    • They can sometimes cause palpitations described as missed or extra beats
    • Ectopic beats are not normally dangerous and don’t damage the heart
  • Atrial flutter
    • Occurs due to the atria beating very rapidly as electricity circulates around this chamber and is commonly seen in middle aged and elderly patients
    • It can occur in those with no other heart problem but also is seen in patients with some form of structural heart disease or who suffer from atrial fibrillation
  • Atrial tachycardia
    • A fairly uncommon arrhythmia but results in the heart beating far more rapidly than normal
    • It is often seen in diseased hearts, although it also occurs in patients with otherwise normal hearts
  • Supraventricular tachycardia
    • Supraventicular tachycardia is a rapid abnormal heart rhythm that begins in the upper chambers of the heart, the atria
    • Symptoms include palpitations, light headedness, dizziness, chest pain, shortness of breath and loss of consciousness
    • In general the majority of supraventricular tachycardias are not a life-threatening condition. Nonetheless, if any of these symptoms develop, immediate medical attention should be sought
    • Most supra-ventricular tachycardias will recur and can be safely and very effectively treated by a procedure called catheter ablation
  • Ventricular tachycardia
    • A fast rhythm originating in the bottom chambers of the heart (the ventricles) which leads heart to beat so rapidly that it cannot fill and pump out enough blood adequately
    • Although it can occur in patients with an otherwise normal heart, it is more commonly seen in patients with heart disease, such as those who have suffered a previous heart attack or have a cardiomyopathy. In these sort of settings, they may be life-threatening and proper assessment and treatment is essential