Capabilities of transesophageal echocardiography in patients with atrial fibrillation

Transesophageal echocardiography is widely used in clinical practice in patients with atrial fibrillation and it is mainly applied to determine the morphology of the heart, the presence of intracardiac thrombi, quantify the structures of the heart, as well as to determine the tactics for surgical interventions. Transesophageal echocardiography has an advantage over transthoracic echocardiography in visualizing the left atrium and left atrial appendage, common sites of thrombus formation in patients with atrial fibrillation. Due to the anatomical proximity of the esophagus to the heart, the transesophageal access avoids signal fading and incorrect interpretation of the study results. The possibilities of transesophageal echocardiography in patients with atrial fibrillation have expanded with the development of medical technology, and three-dimensional transesophageal echocardiography has become widespread. In recent years, the studies on the use of the transesophageal echocardiography in patients with atrial fibrillation during the coronavirus pandemic have been published. The review presents the results of studies, meta-analyzes of pooled samples, as well as clinical cases, demonstrating capabilities of transesophageal echocardiography in patients with atrial fibrillation. A brief history of the development of the method, work on the study of the technology features and capabilities of transesophageal echocardiography for pulmonary vein ablation, cardioversion, occlusion of the left atrial appendage in patients with atrial fibrillation, as well as studies on disadvantages of the transesophageal echocardiography and possible options for their elimination are presented. Comparison of the transesophageal echocardiography with transthoracic and intracardial echocardiography is also highlighted. In preparing the review, the literature search method in PubMed databases for the period 2012–2021 was used, as well as data from an earlier period to indicate the history of the method development. © Eco-Vector, 2022. All rights reserved.

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 thrombosis (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 significantly 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 multivariable 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.

Incremental diagnostic role of left atrial strain analysis in thrombotic risk assessment of nonvalvular atrial fibrillation patients planned for electrical cardioversion.

During the COVID-19 pandemic, transesophageal echocardiography (TEE) for left atrial appendage thrombosis (LAAT) detection should be limited to situations of absolute necessity. We sought to identify the main conventional and functional echocardiographic parameters associated with LAAT on TEE in non-valvular atrial fibrillation (NVAF) patients planned for electrical cardioversion (ECV). This retrospective study included 125 consecutive NVAF patients (71.5±7.8 yrs, 75 males), who underwent TEE at our Institution between April 2016 and January 2020, to exclude LAAT before scheduled ECV. All patients underwent a transthoracic echocardiography (TTE) implemented with speckle tracking echocardiography (STE) analysis of left atrial (LA) strain and strain rate (SR) parameters. 28% of patients were diagnosed with LAAT, while 72% without LAAT. Compared to controls, patients with LAAT had significantly higher CHA2DS2-Vasc Score and average E/e' ratio, and significantly lower left ventricular ejection fraction (LVEF). Moreover, LA-peak positive global atrial strain (GSA+) and LA-SR parameters were significantly reduced in patients with LAAT. Multivariate logistic regression revealed that, differently from CHA2DS2-Vasc Score, LVEF (OR 0.88, 95%CI 0.81-0.97, p = 0.01), average E/e' ratio (OR 2.36, 95%CI 1.41-3.98, p = 0.001), and LA-GSA+ (OR 0.57, 95%CI 0.36-0-90, p = 0.01) were independently associated with LAAT. LA-GSA+ (optimal cut-off ≤ 9.1%, AUC 0.95) showed the highest diagnostic performance. Finally, a strong linear correlation of LA peak-to-peak SR with both LA appendage filling (r = 0.86) and emptying (r = 0.83) velocities was demonstrated. TTE implemented with STE analysis of LA mechanics improves thrombotic risk assessment of NVAF patients.