The left atrial morphologic and functional parameters as predictors of paroxysmal atrial fibrillation in patients after ischemic stroke
Authors: Wilk A , Krol W , Kowalska M , Rozanski D , Braksator W 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Cardiogenic source of embolism is the most common cause of non-lacunar ischemic stroke (IS). Identifying the patients with undiagnosed paroxysmal atrial fibrillation (PAF) may reduce the risk of recurrent cardiogenic strokes. Reliable predictors of PAF seems to be crucial for selection the patients to prolonged ECG monitoring after IS.

Purpose
To assess the feasibility of echocardiography in selecting the patients with highest risk of PAF.

Methods
We present the preliminary data of prospective cohort study of patients after IS or transient ischemic attack of unknown aetiology and possible cardiogenic origin. The examined group comprises of 40 consecutive patients without history of AF, capable to perform ECG recording.
All patients included in the study had transthoracic echocardiography (TTE) prior the monitoring period. An offline analysis including left atrial functional and morphologic assessment was performed. Every patient enrolled in the study was equipped for 2 weeks with a mobile, on demand 1-minute single lead ECG recorder and was asked for at least two exams per day. After two weeks all recorded ECGs were checked for AF occurrence.
The level of statistical significance was set at p&lt;0.05.

Results
From 40 patients (aged 64,5 yrs in average) included in the study 45% were males; (n=18). 15% (n=6) of patients were diagnosed with PAF during ECG monitoring and comprised PAF subgroup, the rest of patients formed non PAF subgroup (nPAF).
Mean number of ECG records was 56,5 per patient, during the monitoring period.
There were no significant differences between PAF/nPAF in age, past medical history, and left ventricular (LV) size or systolic function.
Patients from PAF group have statistically significant higher values of left atrial (LA) area and volume see table 1.
PAF group has significantly lower (in absolute values) left atrial contraction strain – (LASct). There were no differences in conduit and reservoir LA (LASr) strains nor in LA ejection fraction.
The highest PAF diagnosis efficacy according to area under the curve (AUC) of ROC curves was noted for parameters of:
LA size: LA atrium volume index (LAVI) in 4 chamber view (AUC=0,82) and LA area index (0,81)
LA contraction function: LASct (Avg) (AUC =0,80) LV diastolic function: E/E’ (0,81)
For the threshold of 100% sensitivity the highest specificity was found for LA volume before active atrial contraction in 4 chamber view with cut-off value of &gt;=37,6 ml (specificity 64,7%) (Figure 1.) and LASct (Avg) with cut-off value &lt;=17% in absolute values (specificity 47,1%).

Conclusions
Both functional and morphologic parameters of LA can predict PAF diagnosis during ECG monitoring after IS.
TTE after IS can be used to select patients who would benefit the most from prolonged ECG monitoring.
High PAF detectability (100% sensitivity) with approximately 1/2 negative results of ECG monitoring can be achieved by both LA volumetric (LAV preA) and strain (LASct) analysis.