An introduction to atrial fibrillation

Under normal heart health, our heart will pump at a regular rate of 60 to 100 beats per minute to pump the blood out to our systemic cells and organs for perfusion. However, in certain conditions called arrhythmias, our heart tends to pump at an irregular rate either slower or faster than the normal pace. This can be either called tachyarrhythmias or bradyarrhythmias depending on the rate of heart beat.

To understand what is atrial fibrillation, you have to first understand how the heart works to pump the blood out from a so called electric circuit within the chambers. Our heart is divided into 4 chambers, namely 2 atriums and 2 ventricles. The electric signal to start pumping the heart will start at the top corner of the right atrium called the sinoatrial node. The sinoatrial node will send adequate electrical impulses to the left and right atrium to start contract and fill the blood to the ventricles below.

Once the atrium is completely contracted, the signal then reaches the atrioventricular node located at the septum separating the left and right ventricles. Here, the electrical impulses are then transferred through some small fibres around the septum to reach the bottom of ventricles to start pumping them and eventually the blood is pumped out of it.

In atrial fibrillation, the defect in the surface of atrium walls leads to multiple electrical impulses conducted rather than just one impulse generated at the sinoatrial node under normal circumstances. As a result of this, the atrium walls will start to fibrillate leading to irregular heart beats.

Common signs and symptoms of atrial fibrillation will include having palpitations, profuse sweating and chest pain at occasions. Atrial fibrillation is a life threatening disease as it can cause multiple complications like stroke and peripheral vascular diseases due to the migration of thrombus to systemic circulation.

Diagnosing atrial fibrillation can be difficult at times as not all patients will be presented with symptoms of it. An electrocardiogram can be a useful tool to diagnose atrial fibrillation from its pattern which will be an irregular pattern with loss of P waves on it. Some patients where this cannot be detected, a machine will be attached to patients to detect the abnormalities for a period of time at home. Apart from that, other imaging investigations like chest xray and echocardiography can be taken to support the diagnosis of atrial fibrillation.

Causes of atrial fibrillation

There are multiple causes for atrial fibrillation to occur. Most of the causes will lead to alteration of atrium walls leading to formation of multiple center points that generate electrical impulses. It is important to recognize and treat the cause or risk factors to prevent progression of the disease to a worse state. Below are some of the most common causes of atrial fibrillation that can be detected and treated appropriately.

  • Ischemia of the heart

This is commonly known as heart attack in layman terms. Once there is a cut of blood supply due to clot formation, the surface wall which went ischemic will undergo some major alterations leading to these surfaces to generate their own electrical impulses.

  • Thyroid conditions

Thyroid conditions like hyperthyroidism can increase the basal metabolic rate and increase the heart rate leading to atrial fibrillation. Other associated symptoms will include heat intolerance, palpitations and neck swelling in some cases

  • Electrolyte imbalance

Electrolyte imbalances like potassium derangements and magnesium level abnormalities can cause atrial fibrillation as well.

  • Anemia

Anemia can cause the heart to pump much harder than usual due to reduced cardiac output. This can exhaust the surface wall of the heart leading to atrial fibrillation.