Using left atrial strain values and correlating changes in left atrium area and volume size as an early predictor of atrial fibrillation: a prospective, single-centre case-control study
Authors: Hwozdyk L , Cudd T H , Anatoliotakis N , Junejo R T 
Published: January 2025

Abstract

Background
Atrial fibrillation (AF) is the most common type of arrhythmia and is characterised by chaotic, fast, and irregular electrical activity. AF detection is often incidental as patients may be asymptomatic. Turbulent blood flow and poor atrial contraction increase the likelihood of thrombus formation, and ultimately, increase stroke risk. New techniques focussing on LA strain analysis may be able to detect subtle changes within the LA, before gross cardiac structural and electrical remodelling has occurred.

Aim
Differences in LA strain values between three groups: normal sinus rhythm (NSR) and normotensive, NSR and hypertensive, and chronic AF. Correlations between LA strain to LA area and volume size were also investigated as well as the use of LA strain as an early predictor of AF.

Methods
A total of 72 participants were successfully recruited and allocated into one of three groups. 24 participants in the control group, 28 in the disease-control group; and 20 in the disease group. LA strain analysis was performed using the AFI LA atrial strain tool to obtain reservoir (LASr), conduit (LAScd) and contractile (LASct) strain from apical 4- and 2-chamber images. Area and volume (LAVMax) measurements were also obtained, allowing for Pearson’s Correlation Coefficient analysis comparing LA strain values to LA area and volume size. Linear regression was also performed to determine whether a reduction in LA strain may increase the risk of AF development.

Results
All data was found to have normal distribution. A One-Way ANOVA demonstrated that there were statistically significant differences in LA area, LASr (A4C, A2C and Biplane), and LAVMax (A4C, A2C and Biplane). When comparing mean LA area, volume and LASr between the control and disease groups, all p values &lt; 0.001. Average Biplane LASr values are as follows: NSR and normotensive = 25.2% (±6.22%); NSR and hypertensive = 23.3% (± 618%); and AF group = 11.3% (±7.24%). This creates a scale demonstrating the significant reduction in LA strain in AF patients. Pearson’s Correlation indicated that there was a significantly moderate, negative correlation between Biplane LASr and LA area (r = -0.454, p &lt; 0.001, N = 57), and between Biplane LASr and Biplane LAVMax (r = -0.580, p &lt; 0.001, N = 72). Furthermore, a simple bivariate linear regression indicated that an increase in one point in research group type, would correspond, on average, with a decrease in Biplane LASr value by around 0.38 to 0.72 points. Suggesting that as LASr values decrease, the likelihood of AF increases.

Conclusion
LASr values are significantly different between patients in NSR and AF and LASr values correlate negatively with LA area and volume. It is possible to suggest that decreased LASr values, in patients with or without hypertension, can be used as a novel and alternative measure of atrial dysfunction in patients with risk factors for AF; LASr may be able to predict risk of AF development and subsequent progression.