Left Atrial Strain Values as an Early Predictor of Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent type of arrhythmia within an adult population and is characterised by disorganised, chaotic, electrical activity and thus, ineffective atrial contraction causing irregular ventricular contraction. AF can be categorised into three different groups: paroxysmal, persistent and permanent. The prevalence of AF increases with age and is associated with a range of risk factors including: hypertension, obesity and alcohol consumption. There is a plethora of both cardiac and non-cardiac causes of AF and the cause is not always clear for each patient. Furthermore, causes of AF can also present as the by-product of AF, this increases the difficulty in determining the individual patient's cause of onset. A diagnosis of AF can be incidental as not all patients are symptomatic. If AF goes undetected, this puts the patient at an increased risk of blood clot formation and stroke. Patients suspected of having AF are routinely referred for a transthoracic echocardiogram (TTE). It is common for AF patients to have a dilated left atrium (LA). This can be visually confirmed, and the LA area and volume can be measured during a TTE. LA strain measurements are not routinely measured during TTEs but may be able to detect subtle changes in longitudinal strain patterns of the myocardium. By comparing the strain patterns in patients with normal sinus rhythm (control) to those with AF, a scale can be created to suggest and predict whether a patient is likely to develop AF in the future based on these subtle changes before any changes in LA size occur. Furthermore, this can then be further developed to determine whether there are any significant differences in strain patterns between the three AF groups. Objectives: To determine whether there is a significant difference in atrial strain values between patients that are in normal sinus rhythm (NSR, control group) to patients that are known to have atrial fibrillation (disease group). A disease-control group of controlled hypertensive patients in NSR will also be utilised as hypertension is a known risk factor for atrial fibrillation. Providing that there is a significant difference in the values between NSR and AF patients, a further comparison will be conducted on patients in different type of AF: paroxysmal AF, persistent AF and permanent AF to determine if there is a deterioration in atrial strain values within AF patients. Left atrial area and volume size will also be measured in all patients and this can then be compared to atrial strain values.