Diagnosis - Arrhythmias

Arrhythmias
Any disturbance of the normal electrical activity that controls the rhythm of the heart is caused an arrhythmia. There are many different kinds of arrhythmia and the common ones are described in this section. Symptoms experienced by patients with arrhythmias may include palpitations, dizziness and less commonly blackouts.

Extra (ectopic or premature) beats
These are the commonest cause of palpitations and are called ectopic beats. They occur in people of all ages and are nearly always benign. Treatment is often by reassurance alone, although sometimes medications are used.

Supraventricular Tachycardia
Fast heart beats (‘tachycardias’) arising from the top of the heart is called supraventricular tachycardia, or SVT. They are usually caused by extra electrical pathways, and cause rapid palpitations that usually start and stop abruptly. They often respond to medications if treatment is required. Catheter ablation offers a cure in resistant cases or for patients who do not like taking medications. See treatment section, catheter ablation.

Atrial Fibrillation
This is the commonest sustained disturbance of heart rhythm. Causes of atrial fibrillation, or AF, include high blood pressure, alcohol, heart failure, heart valve disease and an overactive thyroid. In younger patients frequently no cause is identified, and AF is believed to be just an electrical disturbance caused by extra beats arising from veins at the back of the heart – the pulmonary veins. AF is an important condition to diagnose for a number of reasons. As well as sometimes causing unpleasant symptoms such as palpitations, shortness of breath and tiredness, AF may increase the risk of blood clots and stroke. Effective treatments are available, including drugs (such as heart rate slowing drugs, rhythm controlling drugs and blood thinners) as well as invasive treatments including catheter ablation. See treatments section, catheter ablation.

Arial flutter
An arrhythmia related to but distinct from AF is called atrial flutter. It is often seen in a similar group of patients to those with AF, and some patients may experience both arrhythmias. Like AF, atrial flutter may cause unpleasant symptoms, and also may place the sufferer at an increased risk of stroke. An important difference from AF is that atrial flutter is a better understood arrhythmia, and catheter ablation treatment is very successful in eliminating it, in approximately 90% of patients. See treatments section, catheter ablation.

Ventricular Tachycardia
This arrhythmia may occur in people with otherwise normal hearts, when it is usually benign. Importantly it is also seen in patients who have a weakened heart often secondary to a previous heart attack. In this setting ventricular tachycardia, or VT, is potentially very dangerous. It commonly presents with severe dizziness or blackouts, and may be life-threatening. Treatment often involves a special sort of pacemaker called a defibrillator. See treatments section, implantable defibrillator.