A Review of Arrhythmias



Patient Perspective Paper 11


These notes are a patient’s view on the subject following a talk given to the Oxford ICD Group by Laura Richmond from the Barts and the London Cardiovascular Biomedical Research Unit. You might like to refer to the various booklets on the subject and these are amongst the stock of information, which I hold and are listed on our website.

I must emphasise once again that notes such as these are very much my personal interpretation and I apologise but take no responsibility for any inaccuracy. If you are worried in any way concerning your own position, please consult your own doctor or consultant. Remember that you have an ICD which monitors you for certain conditions every second of every day, particularly for the very dangerous VF fibrillation.


What is an arrhythmia? A cardiac arrhythmia is when the heart beats too fast, too slowly or irregularly, because of faults within the heart’s electrical system. They are caused by or arise from a range of conditions including heart failure, blackouts, sudden cardiac arrest, stroke or cardiomyopathy. In some cases a damaged heart, as a result of scarring from a heart attack, may cause the problems or in other cases a patient may have completely healthy hearty arteries, valves or heart muscle and yet the “electrics” are faulty. Arrhythmias can occur in the upper chambers (atria) or the lower cambers (ventricles) of the heart.

Detection and monitoring of Arrhythmias. The ideal is of course the ICD itself. This normally has two wires – one to give you a shock in an emergency and the other to detect abnormalities in your sinus rhythm. The latter can be tested using an ECG machine but of course sometimes a person may only experience these disturbances from time to time and the ICD is monitoring 24 hours a day every day.

Monitoring can now take place remotely where the patient has a device at home that will send the readings from their ICD to their hospital using secure encrypted technology. This is now being offered to a percentage of those recently fitted with an ICD.

Common arrhythmia symptoms. Palpitations, irregularity in the pulse rate, dizziness, blackouts, shortness of breath, general lethargy or chest pain might indicate that a patient is suffering from an arrhythmia. It is important however to state that these symptoms might well indicate something else.

Various types of arrhythmia might be:

Atrial fibrillation. This is the most common arrhythmia found in practice. Those who have it have an increased risk of a stroke. It has been found that its prevalence roughly doubles with each 10 years of life.

There are three types of AF:

In these first two cases the AF can be eliminated by suitable treatment but in the third case any treatment will not eliminate it: only reduce it.

Atrial Flutter. This is usually paroxysmal, where the P wave in the ECG has a saw tooth appearance. The rhythm is fast but regular.

Supraventricular tachycardia (SVT). This is present in some between 20 and 40 years of age and is rarely evidence of heart disease. It is not sometimes shown by the ECG and further testing may be required. Some cases are due to an inherited condition called the Wolff-Parkinson-White syndrome (see below). It may degenerate into ventricular arrhythmias.

Ventricular Tachycardia (VT). This is almost always accompanied by palpitations and can be thought of as a sequence of consecutive ventricular premature beats. Sometimes it only occurs a few times or it can be more sustained for longer: in this case it usually occurs with people with structural heart disorder which has damaged the ventricles for instance after a heart attack. Sustained VT can be dangerous, because it may develop into ventricular fibrillation (VF) leading to cardiac arrest. Your ICD will protect you if this happens.

Bradycardia. An adult heart normally beats between 60-80 beats per minute. Infants’ hearts beat faster at about 110-130 beats per minute. If the beat is significantly less than this, the patient is said to be experiencing bradycardia. Slower than average heart beats are common in people who are physically fit or those asleep. Some illnesses and certain drugs used to treat high blood pressure may also slow the beat. There may be no symptoms or a patient may experience dizziness or fainting. Only severe bradycardia (down to <30 beats per minute) becomes dangerous. Any treatment will involve methods to speed up the heart rate, possibly by using drugs or a pacemaker.

Inherited arrhythmias. These may be inherited genetically through the family. They tend to be diagnosed through an ECG machine. In all cases there is a danger that these syndromes might lead into VT and hence cardiac arrest. However treatment may not always involve the use of the implantation of a device.


Treatment of arrhythmias. This can be broken down into different options:


References.

  • AA booklets: CRT/ICD patient information, Cardioversion, Catheter ablation, Drug treatment for heart rhythm disorders, What can I do about sudden cardiac arrest, Genetic testing for inherited heart conditions, Long QT syndrome, Atrial fibrillation patient information, Atrial flutter patient information.
  • BHF booklets: Heart rhythms (No 14), The heart – technical terms explained (No 18)
  • Other sources: Genetic Health, Health Scout, Merck Manual home edition, Univ of Rochester.

Geoff Shaw
GCS/06.01.10