Heart Rhythms

What is a normal rhythm?

The normal electrical pattern of the heart is called sinus rhythm. This means that the impulse comes from the sinus node. The sinus node is the hearts natural pacemaker.

The electrical impulses produced by the sinus node make the atria (the top chambers of the heart) contract and push blood into the ventricles (the bottom chambers of the heart). The impulses travel to the ventricles through the atrioventricular (AV) node.

The impulses then enter the ventricles through fibres which act like wires - the purkinge fibres. When the impulses reach the ventricles they both contract pushing the blood out of the heart to the lungs and the rest of the body.

In a normal heart rhythm each impulse from the natural pacemaker makes the atria and the ventricles contract regularly and in the correct order. While you are resting your hearts pacemaker normally produces between 60-100 beats per minute (bpm). Therefore a normal resting heart rate for an adult is between 60-100 bpm. It is the heart pumping the blood that produces your pulse, which you can feel, for example, at the artery in your wrist. Doctors and nurses can measure the rate and rhythm of your heart by taking your pulse. The rate is how quickly your heart beats and the rhythm is how regular the beats are.

What is a palpitation?

Palpitation is a word that is used to describe the feeling that you get when you are aware of your heart beat. The heart may be beating at a normal rate, quickly, slowly or irregularly or it may feel like it is missing beats.

Although palpitations can feel unpleasant, in most cases they are completely harmless and do not mean that anything is wrong with the heart. The majority of palpitations happen because of ectopic beats. Feeling anxious, stressed or very tired may contribute to palpitations. Smoking, drinking caffeine or excess alcohol many also play a part.

In a small number of cases palpitations may be due to an abnormal heart rhythm.

What is an ectopic beat?

An ectopic beat is an 'extra' beat of the heart and is the most common cause of palpitations. It occurs when cells in another part of the heart release an electrical discharge causing an 'extra' heart beat. There is sometimes a very short a pause after the extra beat has occurred giving the sensation of a 'missed beat'.

Ectopics are very common and most people are totally unaware of them. They can occur in people of all ages and in those with or with out a heart condition. For most people ectopics are completely harmless and do not need any treatment. Feeling anxious, stressed or tired may increase the risk of ectopics, as can smoking, drinking caffeine and excess alcohol.  Avoiding cigarettes, coffee, and alcohol can help to reduce ectopics. If you have been under a lot of pressure recently it may help to take some steps to try and control your stress levels. For more information, please see our booklet Stress and your Heart

In a small number of cases ectopics may indicate that there is an underlying problem with the heart. For people who have an existing heart condition and experience ectopic beats, this may also need investigation.  For more information on Ectopic beats, please see our Fact sheet under our Any Questions section.

What do tachycardia and bradycardia mean?

Sometimes the heart will beat faster or more slowly. This depends on the individual make-up of a person and many other things, such as whether an individual has been active or resting. 

When the heart is beating fast, over 100bpm, it is called sinus tachycardia.

When it is beating slowly, less than 60bpm, it is called sinus bradycardia. 

These are often harmless heart rhythms and do not mean that there is anything wrong with the heart. Also, there may be minor irregularities in the rhythm of your heartbeat which are quite normal.

What is an abnormal rhythm?

An abnormal rhythm is known as an arrhythmia. These can occur when

• The heart is beating at a very fast or a very slow rate
• The electrical impulses come from another part of the heart and not the sinus node, causing the heart to beat irregularly
• The electrical impulses come from the sinus node but go to the bottom of the heart via a different path

One of the most common abnormal heart rhythms is called Atrial Fibrillation. Please see our Any Questions section for more information on Atrial Fibrillation.

For more information on abnormal heart rhythms please see our booklet Palpitations or visit our Any Questions section.

How to do a pulse check

What is Heart Block?

Heart Block occurs when the normal passage of the electrical impulses through the heart is delayed or disrupted.  There are different types of heart block. These include first degree heart block, which generally does not need to be treated and third degree heart block which may require treatment with a pacemaker. For more information please see our Any Questions section or our booklet about pacemakers.

What about Bundle Branch Block?

Bundle branch block is an unusual pattern that shows up on an ECG reading. It is not a condition in itself and may not mean that anything is wrong with the heart. However, it may indicate that there may be some underlying heart disease. Bundle branch block can cause a slight delay in the electrical impulses to the hearts two pumping chambers - the right and left ventricle. If bundle branch is picked up it may lead to a need for further tests on the heart. For more information on bundle branch block please see please see our Any Questions section.

How are heart rhythm problems diagnosed?

The doctor will want to listen to your heart through a stethoscope and will ask you about any symptoms you are having and when they occur.   To help diagnose an abnormal heart rhythm an ECG (electrocardiogram) recording will be performed. For more information on the tests that may be involved please see our our section on Tests and our booklet Tests for heart conditions.

What about treatments?

Treatments will vary greatly depending on the type of heart rhythm problem and the individual person. The cardiologist or heart specialist will need to assess each individual case and prescribe any treatment necessary.  For more information on types of treatments, please see our booklets Palpitations and Pacemakers and see the Treatments section of our website.   

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