Left atrial appendage function assessment and thrombus identification

Abstract

BackgroundThe diagnosis of thrombus in the left atrium in patients with persistent atrial fibrillation (AF) and may be inconsistent because of variability in thrombus morphology. In some cases it is challenging and requires unusual approach. New Doppler-derived methods might be helpful to identify such thrombi. We evaluated quantitative differences in mechanical function of the left atrial appendage (LAA) basal segments using tissue Doppler imaging (TDI)and speckle tracking echocardiography (STE) in patients with non-valvular AF with and without LAA thrombus and compared them with SR patients.MethodsA total of 80 patients with normal left ventricular ejection fraction underwent transesophageal echocardiography (40 patients with SR and 40 patients with AF on oral anticoagulants including patients with LAA thrombus). We analyzed the basal segments of LAA including left lateral ridge (LLR) and baso-medial appendage segment (BMAS). Quantitative analysis was used to calculate peak velocity, average velocity, strain, strain rate and deformation.ResultsIn patients with AF the lower LLR strain rate was the sole new STE significant parameter differentiating patients with and without LAA thrombi: − 0.9(− 1.2; − 0.1)s− 1 vs. − 1.6(− 1.9; − 1.3)s− 1, (p = 0.004). Additionally, patients in SR demonstrated significantly better peak velocity, average velocity, strain, strain rate and deformation than those with AF (p < 0.001).ConclusionsLLR appeared to be an appropriate site for measuring Doppler derived parameters. It is possible that the strain rate in LLR area may be a novel parameter correlating with the presence of thrombus in patients with AF.

Atrial appendages’ mechanics assessed by 3D transoesophageal echocardiography as predictors of atrial fibrillation recurrence after pulmonary vein isolation

“…LA systolic function decreases after PVI despite significant decrease in LA volume, within the stiff LA syndrome which is a consequence of LA myocardium scar formation [19] , [20] , [21] . However, LAA volume enlarges after PVI and due to scar formation including > 30% of the LA endocardium, LAA contraction accounts for>50% of complete LA contraction [14] , [21] , [22] , [23] , [24] . Moreover, the higher the LAA peak flow velocity, the greater the likelihood of sinus rhythm maintainance after cardioversion and ablation procedures.…”

“…Also, these two 3D-TEE LAA's parameters proved as significant predictors of AFR after ablation both in univariate and multivariate Cox regression analyiss, which was corrected for most usual AFR risk factors (age, sex, body mass index, hypertension). Moreover, Kurzawski et al showed that the lower values of LAA's lateral wall strain rate is a significant predictor of thrombi formation within LAA, regardless of the AF type and underlying rhythm during TEE assessement [14] . Our study also showed that a lower LAA ostium surface area is predictive for AFR.…”

“…The parasternal long axis (PLAX) LA diameter was measured at end diastole. For 2-dimenssional LA volume quantification (in mililiters), modified Simpson’s biplane volume equation was used [14] . Indexed 2D left atrial volume (LAVI, ml/m 2 ) was calculated by dividing the estimated end-systolic LA volume with the body surface area (m 2 ) [13] , [14] .…”

“…LAA ostium surface area and SVC ostium surface area were assessed by real-time 3D TEE using the same transducer. LAA images were obtained in the long axis view (bypositioning the transducer in a range of 50-110°) at the left lateral wall/ridge in the view which included appendage itself, LA cavity, left superior pulmonary vein, mitral valve and basal parts of left ventricle [14] . RAA TDI tissue velocity and SVC ostium surface area were assessed in the midoesophageal bicaval view (transducer in a range of 90-120° with a clockwise rotation).…”

Left atrial appendage isolation during ablation in the interatrial septum: Rapid recognition by continuous monitoring of appendage electrograms

“…The ablation lesion sets used over the past 15 years in ablating AF and AT can block many of the interatrial pathways (Figure ), endangering interatrial conduction. Partial block potentiates re‐entry; total block can isolate the LA body and LAA, facilitating thrombus formation …”