Echocardiographic markers for left atrial stiffness and left atrial conduction delay in patients with silent paroxysmal atrial fibrillation compared to age-matched controls.
Indices reflecting LA stiffness and atrial conduction delay were significantly elevated in recently diagnosed PAF patients, and LASI and LA-AT thresholds might non-invasively detect early atrial remodeling without structural enlargement in elderly patients with high risk of PAF and mildly increased NT-proBNP levels.
Key Findings
Results
Older adults with newly diagnosed silent paroxysmal AF had significantly higher left atrial stiffness index (LASI) than age-matched controls.
LASI was 0.41 (0.29-0.60) in the PAF group (n = 67) vs. 0.32 (0.29-0.43) in controls (n = 94), P = 0.001.
LASI was calculated as the ratio of left ventricular filling (E/e') to peak atrial longitudinal strain (PALS).
Participants were enrolled from the STROKESTOP2 study; mean age was 76 ± 0.3 years, and all had NT-proBNP levels of 125-900 ng/L.
Results
Left atrial activation time (LA-AT) was prolonged in the PAF group compared with controls.
LA-AT was 170 (140-180) ms in PAF vs. 140 (120-144) ms in controls, P < 0.001.
LA-AT was measured as the time delay between the onset of the ECG P-wave and the tissue Doppler A' peak wave in the lateral LA wall.
TTE examinations were analyzed retrospectively offline using dedicated software.
Results
LASI and LA-AT remained significantly different between PAF patients and controls among participants with normal left atrial volume index.
Subgroup analysis used LAVI ≤ 34 ml/m2.
The subgroup comprised 27 PAF participants and 72 controls.
LASI and LA-AT remained significantly increased/prolonged in PAF in this subgroup, suggesting changes without structural LA enlargement.
Results
NT-proBNP levels did not differ between PAF patients and controls.
NT-proBNP was 228 (181-348) ng/L in PAF vs. 216 (156-317) ng/L in controls (P = 0.18).
All participants had mildly elevated NT-proBNP (125-900 ng/L) by inclusion criteria.
Results
ROC curve analysis identified thresholds of LASI and LA-AT for discriminating silent PAF.
The identified thresholds were LASI > 0.54 and LA-AT > 139 msec.
The authors suggest these thresholds might non-invasively detect early atrial remodeling in elderly patients at high risk of PAF with mildly increased NT-proBNP.
What This Means
This study compared older adults (average age about 76) who had been newly found to have silent, intermittent atrial fibrillation (an irregular heart rhythm) with similar-aged people without it. All participants came from a screening program and had mildly raised levels of a blood marker of heart strain (NT-proBNP). Using ultrasound heart scans, the researchers measured how stiff the left atrium (an upper heart chamber) was and how long electrical activation took to travel through it.
People with silent atrial fibrillation had a stiffer left atrium and slower electrical conduction than controls. These differences were still present in people whose left atrium was not enlarged, while the blood marker NT-proBNP did not differ between the groups. The researchers identified cut-off values for the two ultrasound measures (stiffness index above 0.54 and activation time above 139 milliseconds) that could help tell the groups apart.
This research suggests that these ultrasound measures may pick up early changes in the atrium that standard size measurements and the blood test miss. Because this was a retrospective analysis of a relatively small group at one point in time, it shows association rather than prediction, and the cut-offs would need confirmation in other studies before any use in clinical practice.
Bastos L, Al-Khalili F, Bäck M, Manouras A, Engdahl J, Shahgaldi K. (2026). Echocardiographic markers for left atrial stiffness and left atrial conduction delay in patients with silent paroxysmal atrial fibrillation compared to age-matched controls.. Cardiovascular ultrasound. https://doi.org/10.1186/s12947-026-00395-1