Anticoagulants and dentistry
Atrial fibrillation
The most common reason for patients to be on anticoagulants is to prevent strokes due to atrial fibrillation (AF). AF is a very common heart condition in older people. In the UK every year about 200,000 new cases are diagnosed. People with AF may not know they have it, or may experience mild symptoms like palpitations, dizziness and shortness of breath.
Life-long anticoagulant drugs are used to prevent these clots forming in AF patients, and often the risk of stroke is reduced to normal levels.
Atrial fibrillation mechanism
A healthy heartbeat starts with a single electrical signal at the sino-atrial node (SA), which is near the top of the right atrium. The SA node is the heart’s natural pacemaker. As the electrical signal spreads away from the node, it causes the atria to contract, squeezing blood into the ventricles.
The SA node electrical wave continues travelling, and reaches the atrio-ventricular node (AV) further down. When it is received, the AV node sends out other signals (via the His-Purkinje system) which cause the ventricles to contract in a unified way.
Sometimes, the “initial” signal comes not just from the SA node, but from multiple other areas of the atria more… that have unfortunately developed the ability to fire similar electrical signals. These cause the atrial muscles to quiver erratically, like a bag of worms – Atrial Fibrillation. The commonest place for these ectopic foci is in the pulmonary vein that enters the left atrium.
These erratic signals reach the AV node at irregular intervals, causing the heart’s ventricles to beat irregularly and (because there are many signals) quickly – from 100 to 200 beats per minute.
Normal ECG
Atrial fibrillation
