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What is Heart Block?

By: Jo Johnson - Updated: 1 Jan 2013 | comments*Discuss
 
Heart Block First Degree Third Degree

Heart block is a term given to a condition when the upper chambers of the heart do not send signals to the lower chambers of the heart properly or sometimes at all. In the upper chambers part of the anatomy is called the sinoatrial node (SA node), which triggers the electrical impulses through the upper sections of the heart and passes it to the atrioventricular node (AV node), which conducts the electricity through the lower chambers of the heart. Sometimes the communication between the two does not occur properly or is lost entirely, this is known as heart block. There are three classification of heart block depending on the severity of the signal transmission failure; these are called first, second and third degree heart block.

First Degree Heart Block

This type of heart block is diagnosed when the signals passing through the AV node occur more slowly than normal. It is quite common in those who are very fit, or as a side effect of certain medications. It is not normally serious and often no treatment is required as heart rate and rhythm are usually unaffected.

Second Degree Heart Block

Second degree heart block is divided into two further categories: type 1 and type 2. Type 1 of this group occurs when the signals are interrupted and slowed until they become more and more delayed until eventually the beat is skipped entirely. Although it can cause feelings of dizziness and faintness, it is not very serious and sometimes is left untreated.Type 2, is more serious as the signals from the upper chamber do not reach the lower chambers properly, slowing the heart rate so much so that often a pacemaker will need inserting to regulate the heart rate and keep it beating in a strong regular pattern.

Third Degree Heart Block

The most serious form of heart block, it means the signals from the atria, do not reach the ventricles at all leading to a very slow heart rate and overall poorly functioning heart. It can be an emergency as the person is at risk of cardiac arrest and can also suffer from the consequences of dysfunction of the heart muscle. It is often a side-effect of heart disease but can be present at birth and is treated by the use of a pacemaker.

Signs and Symptoms

For those diagnosed with first degree heart block, there may be no obvious symptoms at all but as the condition becomes more serious leading into second and third degree, breathless, dizziness, chest pain and palpitations are likely.

Diagnosis

Heart block can be diagnosed using one or all of the following tests: and electrocardiogram, which monitors the electrical activity in the heart, blood tests, a 24 hour tape, which records the heart beats over 24 hours, and echocardiogram, which involves visualising the heart under ultrasound scan or by using electrophysiology, which tests the conductivity of the heart tissue using tiny electrical impulses.

Risks of Heart Block

If heart block is serious, there is significant risk of suffering from a stroke or heart attack. Any symptoms relating to the heart must be professionally diagnosed and treated effectively in order to prevent more serious injury occurring.

Heart block can be both non-serious and require no active treatment, or it can be life threatening if left untreated depending on the type of heart block diagnosed. It is important to seek medical advice if any of the mentioned symptoms are experienced.

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