Introduction

Atrial fibrillation (AF) is one of the most common forms of heart arrhythmias found in the modern world. It can have quite a profound impact on the quality of life of those suffering due to the range of symptoms that it can cause as well as the other health implications that come along with it. Even when treatment has been provided, atrial fibrillation can recur in the future due to different issues with the heart; One of which being left atrial enlargement. Alongside other circulatory issues, uncontrolled AF can also lead to an increased risk of stroke development and thus need to be adequately monitored and maintained. 

Atrial Fibrillation

Statistically, 1 in 5 people over the age of 45 suffer from AF in their lifetime, making incidence of AF quite common. It is also the most common type of arrhythmia seen in healthcare settings. Oftentimes, onset of AF is linked to other cardiac or circulatory issues like heart attack, stroke and heart failure as well as dementia.¹ A scientific phenomenon known as ‘Virchow’s Triad’ can be used to explain why AF occurs in the body. In the case of AF, the vessel wall abnormalities that can happen usually coincide with the onset of AF as the heart chambers and vessels weaken over time and with other concurrent medical conditions affecting the pumping of the heart.²

The main symptoms often associated with AF are dizziness, shortness of breath, fatigue when both exercising and resting, chest pains and a tachyarrhythmia. Usually, hospitals will organise special testing to monitor the heart including ECGs and echocardiograms to check the quality of the heart pumping system. A typical ECG positive for AF would include a very fast heartbeat, typically over 100 and often reaching closer to 200 beats per minute as well as absent p waves on the ECG trace.³

Left Atrial Enlargement

In left atrial enlargement, there is an abnormal change in the size of the left atrium that isn’t usually seen in healthy hearts. This increase in size of the chamber is thought to occur due to increases in atrial pressure where there are long periods of increase and fewer periods of relaxation and lower pressures. Often, pressure changes can be linked to other heart conditions that include high blood pressure, mitral valve disease and heart failure as well as in larger or obese populations. It has also been found that males are more likely to develop left atrial enlargement than their female counterparts.⁴

Over time, the consistent enlargement of the left atrium can cause fibrosis and remodeling of the very thin, muscular wall of the heart. These changes away from the normal anatomy of the heart means that normal atrial contraction is disrupted leading to an increased risk of arrhythmia onset like AF. If someone is found to have heart failure or AF coinciding with left atrial enlargement then they have a poorer prognosis than those without the addition of the enlargement.⁵

Treatment and Prevention

There has been some research into understanding how the remodelling of the enlarged left atrium can be halted or reversed with some success. Traditionally, controlling the modifiable risk factors of heart diseases including increasing healthy lifestyles, reducing alcohol and smoking, lowering cholesterol and working to lower blood pressure through diet, stress reduction and pharmacological options. Often, patients will be prescribed blood pressure lowering medications like ACE inhibitors and ARBs, these are typically taken once or twice a day for life if blood pressure is controlled using them. It has been shown that by treating these conditions with both drug types, the risk of AF episodes is greatly reduced.⁶

In AF there are two avenues to go down when deciding what treatment option is preferred for each patient. Medications or interventions can either be used to control heart rhythm or to control heart rate.⁷ If AF is persistent and doesn’t respond to first line medications, a very good option would be to undergo an intervention to reset the heart back to a normal rhythm. This intervention is very commonly used in practice and is known as cardioversion as well as the use of catheter ablation to reset the heart.⁶  If cardioversion is used however, there are strict rules that must be followed in order to reduce the risk of a stroke that is associated with AF. Anticoagulation using blood thinners are usually prescribed to those with AF and are taken lifelong.⁷ There are risk tools used by doctors in order to determine whether or not someone will need anticoagulation following AF and how risky it would be to give them this medication.

Other less invasive ways to reduce the risk of AF recurrence in left atrial enlargement would be to use more simple medication that can be taken once a day in order to control the heart rate. These usually come with very little risk and side effects and are less likely to cause hospital admissions in relation to future AF. There are few different medications to use in this choice depending on the specific needs of the patient. These include beta blockers, digoxin and calcium channel blockers (CCBs).⁸ If people would prefer to not have surgical interventions or try tablets straight away, risk modification programmes can be offered in which they focus on lowering blood pressure and changing diet and smoking habits. This has had a very startling improvement on AF survival rates with the current rate being at 87% if followed correctly.⁸

Summary

Atrial Fibrillation is a very common heart arrhythmia that affects many in later life. It can coincide with other circulatory abnormalities and is often associated with cases of high blood pressure for long periods of time. In left atrial enlargement, the constant elevated pressures affecting the left side of the heart have a dramatic impact on the strength and health of the thin left atrial wall, often leading to the onset of AF symptoms. This poses a significant risk to those suffering from these diseases as quality of life is vastly reduced and there is a much higher risk of sudden death due to the rapid firing of the heart. Luckily, in modern medicine, there are many ways in which we can adequately control the heart rhythm and rate in order to reduce the risk of AF recurrence in the future. There have also been studies that show heart remodelling can be reversed somewhat, when a healthy diet and lifestyle is followed closely over a long period of time. This is good news for those suffering from left atrial enlargement that have yet to experience AF as they may still have a chance or reversing a portion of the damage done and reducing the risk of AF occurrence.