Mechanical concordance between left atrium and left atrial appendage in nonvalvular atrial fibrillation: can it be exploited to avoid transesophageal echocardiography prior to electrical cardioversion during Covid‑19 pandemic?

Transesophageal echocardiography (TEE) is the gold standard for assessing left atrial appendage (LAA) mechanic and throm-
bosis (LAAT); however, TEE is a high-risk procedure for viral transmission during coronavirus disease 2019 (COVID-19) 
pandemic. We investigated whether deformation indices of left atrium (LA) at transthoracic echocardiography (TTE) correlate 
with those of LAA assessed by TEE in nonvalvular atrial fibrillation (NVAF) patients undergoing electrical cardioversion 
(ECV). Consecutive patients with NVAF of ≥ 48 h or unknown duration, who underwent TEE and TTE at our Institution 
before ECV were retrospectively investigated. Standard echo-Doppler and LA and LAA myocardial strain and strain rate 
parameters were analyzed. A total of 115 NVAF patients (71.3 ± 8.1 yr/o, 59.1% men) were included: LAAT was diagnosed 
in 25 (21.7%) patients. Compared to patients without LAAT, those with LAAT had significantly higher  CHA2DS2-VASc 
Risk score (4.5 ± 1.4 vs. 3.5 ± 1.1, p < 0.001), and lower ejection fraction (46.0 ± 14.8 vs. 57.6 ± 8.6%, p < 0.001). In LAAT 
patients, global strain of LA (8.7 ± 2.6 vs. 16.3 ± 4.5%, p < 0.001) and LAA (7.0 ± 1.7 vs. 11.7 ± 2.0%, p < 0.001) was sig-
nificantly reduced compared to non-LAAT patients. A close relationship between left atrial strain reservoir (LASr) and 
LAA-global strain was demonstrated (r = 0.81). By univariable analysis, CHA2DS2-VASc Risk Score (OR 2.01, 95%CI 
1.34–3.00), NT-proBNP (OR 1.36, 95%CI 1.19–1.54), ejection fraction (OR 0.92, 95%CI 0.88–0.96), E/e’ ratio (OR 2.07, 
95%CI 1.51–2.85), and LASr (OR 0.39, 95%CI 0.25–0.62) were strongly associated with LAAT presence at TEE. By mul-
tivariable analysis, only LASr (OR 0.40, 95%CI 0.24–0.70) retained statistical significance. ROC curve analysis revealed 
that an LASr cut-off value ≤ 9.3% had 98.9% sensibility and 100% specificity to identify LAAT by TEE (AUC = 0.98). In 
patients with NVAF of ≥ 48 h or unknown duration, scheduled to undergo ECV, LA deformation assessment by TTE might 
substitute invasive measurement of LAA function by TEE, simplifying diagnostic approach and possibly contributing to 
reduce COVID-19 infection diffusion.