Cardiac arrhythmia

What is cardiac arrhythmia?

Palpitations are the feeling that the heart is beating abnormally or an abnormal throbbing sensation. An abnormal heart rhythm can be seen in an echocardiogram in only 40% of people who complain of palpitations. Cardiac arrhythmia may result in the heart racing, beating very slowly or beating irregularly.

If the heart rate is very slow – less than sixty beats a minute – the heart rate is considered to be slow and the term used is 'bradycardia'. This may be caused by, for example, medication, a slow thyroid or a condition of the heart itself.

In tachycardia, the heart beats faster: more than one hundred beats a minute. This can be the result of factors such as exertion, pain, anxiety, a fast thyroid, anaemia or atrial fibrillation.

An irregular heartbeat causes an extra heartbeat occasionally. This can be caused by anxiety, exertion or a condition affecting the cardiac valves.

What are the complaints associated with cardiac arrhythmia?

The symptoms of cardiac arrhythmia can vary widely: fatigue, dizziness, fainting or almost fainting, concentration problems, impaired memory, palpitations, lightheadedness, chest pain or the feeling that the heart keeps skipping a beat.

People with intellectual disabilities sometimes find it impossible to communicate these symptoms. The people around them may then notice only a change in behaviour.

How common is cardiac arrhythmia in the general population?

An irregular heart rate is found in 1 to 4%. ²³⁰
The one-year prevalence for cardiac arrhythmia caused by atrial fibrillation is 0.5% (this increases with age: from 0.04% in people aged between 25 and 45 years to 6% in people aged 75 years and over). ²³¹

How common is cardiac arrhythmia in people with intellectual disabilities?

This is not known. There is no reason to assume that cardiac arrhythmia is less common in people with intellectual disabilities.