Evaluation of Left Atrial Function by 2D Speckle-Tracking Echocardiography in Patients With Vasovagal Syncope

Vasovagal syncope (VVS) is the most common cause of syncope and is traditionally attributed to autonomic dysregulation and reduced preload. Recent evidence suggests that left atrial (LA) size and function may influence susceptibility to syncope. Two-dimensional speckle-tracking echocardiography (2D-STE) allows detailed assessment of LA mechanics. This study aimed to evaluate LA structure and function in patients with VVS using conventional echocardiography and 2D-STE.

This study included 100 participants recruited from Al-Zahraa University Hospital between January and December 2025: 50 patients with head-up tilt test (HUTT)-confirmed VVS and 50 healthy controls. All subjects underwent clinical assessment, electrocardiography, conventional transthoracic echocardiography, tissue Doppler imaging, and 2D speckle-tracking echocardiography (2D-STE). Left atrial dimensions, volumes, and functional indices were measured. LA strain parameters including reservoir (S-R), conduit (S-CD), and contractile strain (S-CT) were derived from apical views. Data were analyzed using SPSS version 27, with p < 0.05 considered statistically significant.

Compared with controls, VVS patients exhibited significantly smaller LA dimensions and volumes. LA volume was markedly reduced in the VVS group (30.30 ± 8.77 vs. 43.60 ± 10.54 mL, p < 0.001), as was the LA volume index (17.30 ± 4.27 vs. 24.79 ± 5.31 mL/m², p < 0.001). Speckle-tracking analysis demonstrated significant impairment of LA reservoir strain (35.9 ± 8.26 vs. 43.36 ± 8.90, p < 0.001) and LA contractile strain (-10.48 ± 3.82 vs. -14.6 ± 4.5, p < 0.001) in VVS patients. No significant difference was observed in LA conduit strain.

Patients with vasovagal syncope (VVS) may have smaller left atrial size and impaired atrial mechanical function, particularly in reservoir and contractile phases. Left atrial strain assessment by 2D speckle-tracking echocardiography (2D-STE) may provide incremental value in identifying atrial involvement in VVS and offers a potential noninvasive marker for syncope susceptibility.