Left atrial functional remodeling in lone atrial fibrillation: a two-dimensional speckle tracking echocardiographic study

Left Atrial Appendage Mechanical Dispersion Assessed by Speckle-Tracking Echocardiography as a Determinant of Left Atrial Appendage Blood Stasis in Patients With Atrial Fibrillation

Aims

We sought to investigate the relationship of left atrial appendage (LAA) mechanical dispersion (MD) with LAA dense spontaneous echo contrast (SEC) or thrombus, and to compare its usefulness in the identification of thrombogenesis with left atrial (LA) MD or LA/LAA strain parameters in patients with atrial fibrillation (AF).

Methods

We conducted a cross-sectional study of 493 consecutive patients with AF [65(58.5–71.0) years, male 66.9%] who underwent echocardiography prior to catheter ablation. We measured the LAA and LA global longitudinal strain (GLS) using speckle-tracking echocardiography (STE). LAA MD and LA MD was defined as the standard deviation (SD) of time to peak positive strain corrected by the R-R interval.

Results

Patients with LAA dense SEC/thrombus (n = 70) had significantly higher LAA MD than controls (n = 423) [median 14.2(11.6–16.8)% vs 9.4(6.2–12.1)%, p < 0.01]. Multivariable analysis showed that LAA MD was independently associated with LAA dense SEC/thrombus in four different models (Odds ratio, 1.23–1.24; p < 0.01), and provided additional diagnostic value over clinical and standard echocardiographic parameters. Whereas, LA MD was not independently associated with LAA dense SEC/thrombus and had no incremental value over other LA/LAA mechanical parameters.

Conclusion

LAA mechanical dispersion was an independent determinant of LAA dense SEC/thrombus in AF patients, incremental to conventional risk factors and superior to LA mechanical dispersion.

Speckle-tracking echocardiography can predict atrial fibrillation in patients with supraventricular tachycardia

PURPOSE

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common supraventriculer arrhythmia in daily clinical practice. Comorbidity of AVNRT and atrial fibrillation (AF) has been well documented in some patients and AF development has been observed more frequently in AVNRT patients during their long-term follow-up. This study was conducted in order to investigate the left atrial two-dimensional-speckle-tracking echocardiographic (STE) parametres as the predictors of the occurence of AF in long-term follow-up in patients with spontaneously developed AF during AVNRT ablation.

METHODS

Two hundred and thirty two consecutive AVNRT patients who developed spontaneous AF during ablation procedure were included in the study. The patients were followed up for a mean follow-up period of 6.2 ± 2.1 years. All patients were evaluated using the 2D-STE method. AF was developed in 34 patients during the follow-up period. Cox regression analysis was performed in order to identify the independent predictors of AF occurence.

RESULTS

Left atrial LA-res, LA-pump, LA-SRs, LA-SRe, and LA-SRa values were found to be significantly decreased in the group of patients that developed AF during the follow-up period (p < .001 for all aforementioned values). Multivariate cox regression analysis revealed that LA-res (hazard ratio [HR], 0.367; 95% confidence interval [CI], 0.161-0.0.683, p < .001) and SRe (HR, 0.472; 95% CI, 0.346-0.825, p = .006) were independent risk factors associated with the occurrence of AF.

CONCLUSION

In conclusion, it was demonstrated for the first time with this study that 2D-STE can effectively predict the development of AF in long-term follow-up in patients with spontaneously developed AF during AVNRT ablation.

Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain

Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

Decreased longitudinal systolic strain rate of the left atrial myocardium as one of the earliest markers of atrial cardiomyopathy in subjects with brief paroxysmal atrial fibrillation

PURPOSE

Brief paroxysmal atrial fibrillation (BPAF) is defined as episodes of atrial fibrillation (AF) lasting less than 30 seconds and can be a sign of atrial cardiomyopathy. We aimed to evaluate left atrial (LA) function in patients with BPAF.

METHODS

This cross-sectional prospective study consecutively recruited 42 patients with BPAF on 24 to 48 hour electrocardiography Holter monitoring. We selected 50 volunteers as the control group after 24 hours electrocardiography Holter monitoring. Two-dimensional speckle-tracking echocardiography was performed to evaluate the longitudinal deformation variables of LA function.

RESULTS

Strain rate during LA reservoir phase was lower (P = .018) in patients with BPAF (2.0 ± 0.4 second^-1 ) than in controls (2.2 ± 0.5 second^-1 ). This difference remained significant after adjustments for left ventricular ejection fraction, LA maximal volume, and diabetes (β = 0.222, P = .036). Strain during LA reservoir, conduit, and contraction phases and strain rate during the conduit and contraction phases were not significantly different between the two groups.

CONCLUSIONS

The reservoir function of the LA evaluated by two-dimensional speckle-tracking echocardiography was lower in subjects than that without BPAF.

Combined assessment of left atrial volume parameters for predicting recurrence of atrial fibrillation following pulmonary vein isolation in patients with paroxysmal atrial fibrillation

OBJECTIVES

Our aim was to test the hypothesis that comprehensive simplified left atrial (LA) assessment derived from routine echocardiography may be more useful than assessment of LA volume alone for predicting atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI).

METHODS

We studied 156 patients with paroxysmal AF (PAF) who had undergone PVI. Echocardiography was performed within two days before PVI. Maximum (Max-LAVi) and minimum LA volume index (Min-LAVi) were calculated with the biplane modified Simpson's method, and then normalized to the body surface area. On the basis of previous findings, the predefined cutoff value of Max-LAVi for AF recurrence was set at Max-LAVi ≥ 34 mL/m² . ΔLA volume index (ΔLAVi) was also calculated as Max-LAVi minus Min-LAVi. The follow-up period after PVI was 24 months.

RESULTS

AF recurrence was observed in 35 patients. Multivariate logistic regression analysis showed that ΔLAVi (odds ratio [OR]: 1.131; 95% confidence interval [CI]: 1.057-1.221; P < 0.001) was an independent predictor of AF recurrence. Sequential logistic regression models for predicting AF recurrence revealed that a model based on clinical variables including age, gender and AF duration (χ²  = 1.65) was improved by the addition of Max-LAVi ≥ 34 mL/m² (χ²  = 13.8; P < 0.001), and further improved by the addition of ΔLAVi (χ²  = 18.2; P = 0.036). Of note is that only 1.02 ± 0.10 minutes per patient was needed to obtain a comprehensive LA assessment that included Max-LAVi, Min-LAVi, and ΔLAVi.

CONCLUSION

This easy-to-use comprehensive simplified LA approach from routine echocardiography may well have clinical implications for better management of PAF patients.

Assessment of left atrial remodeling in paroxysmal atrial fibrillation with speckle tracking echocardiography: a study with an electrophysiological mapping system

This study aimed to evaluate left atrial (LA) remodeling and fibrosis in paroxysmal atrial fibrillation (AF) using speckle tracking echocardiography (STE) based on the findings with radiofrequency catheter ablation (RFCA) so as to predict atrial remodeling prior to ablation. A total of 40 patients with paroxysmal AF were enrolled and divided into two groups based on LA bipolar voltage detected during RFCA: those with low-voltage zone (LVZ) (LV group, n = 19) and those without LVZ (non-LV group, n = 21). The segmental and global LA reservoir, conduit and contractile strain (εs, εe, εa) were analyzed using two-dimensional STE before RFCA. The segmental and global εs, εe, εa (%) decreased in the LV group. Especially, the εs in anteroseptal upper (18.32 ± 7.94 vs. 31.61 ± 9.39) and lower segments (16.60 ± 7.23 vs. 29.23 ± 9.81), posteroseptal upper (22.24 ± 6.65 vs. 32.23 ± 10.57) and lower segments (18.24 ± 6.49 vs. 26.40 ± 7.12), and the global εs (23.85 ± 6.74 vs. 30.48 ± 8.67) significantly decreased in the LV group than in the non-LV group (all P < 0.05). The εs ≤ 24.07 in the anteroseptal upper segment was an effective parameter to differentiate the LV group (sensitivity, 84%; specificity, 81%, P < 0.001). Besides, global εs tended to be an independent determinant of the LVZ (odds ratio 1.347, P = 0.046). STE enables a noninvasive method to evaluate LA remodeling prior ablation.

Left atrial strain assessed by three-dimensional speckle tracking echocardiography predicts atrial fibrillation recurrence after catheter ablation in patients with paroxysmal atrial fibrillation

BACKGROUND

Several studies have shown the utility of left atrial (LA) function determined by two-dimensional or three-dimensional speckle tracking echocardiography (2D- or 3D-STE) for identifying patients with paroxysmal atrial fibrillation (AF). However, whether 3D-STE is applicable for prediction of the recurrence of AF after catheter ablation (CA) remains unknown. We examined whether any 3D-STE parameters are better than 2D-STE parameters for the prediction of AF recurrence.

METHODS

Forty-two patients with paroxysmal AF (58 ± 10 years old, 69% male) underwent 2D- and 3D-STE within 3 days before first-time CA. The global peak LA longitudinal, circumferential, and area strains during systole (3D-GLSs, -GCSs, and -GASs, respectively) and those just before atrial contraction (3D-GLSa, -GCSa, and -GASa, respectively) were determined by 3D-STE and standard deviations of times to peaks of regional LA strains were calculated as indices of LA dyssynchrony. In 2D-STE, global LA longitudinal strains during systole and just before atrial contraction (2D-GLSs and -GLSa) were determined.

RESULTS

During follow-up of 441 ± 221 days, 12 patients (29%) had AF recurrence. In the univariate Cox proportional hazard analysis, age [hazard ratio (HR): 1.08, p = 0.04], 3D-GCSs (HR: 0.91, p = 0.03), and 3D-GASs (HR: 0.95, p = 0.01) were predictors of AF recurrence, though associations of recurrence with 2D-STE parameters, indices of LA synchrony, and LA volume were not significant. Multivariable analysis showed that 3D-GASs was an independent predictor of AF recurrence (HR: 0.96, p = 0.048).

CONCLUSIONS

LA strain determined by 3D-STE is a novel and better predictor of AF recurrence after CA than that determined by 2D-STE or other known predictors.

Methodological Gaps in Left Atrial Function Assessment by 2D Speckle Tracking Echocardiography

The assessment of left atrial (LA) function is used in various cardiovascular diseases. LA plays a complementary role in cardiac performance by modulating left ventricular (LV) function. Transthoracic two-dimensional (2D) phasic volumes and Doppler echocardiography can measure LA function non-invasively. However, evaluation of LA deformation derived from 2D speckle tracking echocardiography (STE) is a new feasible and promising approach for assessment of LA mechanics. These parameters are able to detect subclinical LA dysfunction in different pathological condition. Normal ranges for LA deformation and cut-off values to diagnose LA dysfunction with different diseases have been reported, but data are still conflicting, probably because of some methodological and technical issues. This review highlights the importance of an unique standardized technique to assess the LA phasic functions by STE, and discusses recent studies on the most important clinical applications of this technique.

Evaluation of left atrial function in patients with iron-deficiency anemia by two-dimensional speckle tracking echocardiography

Background

Iron-deficiency anemia (IDA) is a global health problem and a common medical condition that can be seen in everyday clinical practice. And two-dimensional speckle tracking echocardiography (2D-STE) has been reported very useful in evaluating left atrial (LA) function, as well as left ventricular (LV) function. The aim of our study is to evaluate the LA function in patients with IDA by 2D-STE.

Methods

65 patients with IDA were selected. This group of patients was then divided into two groups according to the degree of hemoglobin: group B (Hb > 90 g/L) and group C (Hb60 ~ 90 g/L). Another 30 healthy people were also selected as control group A. Conventional echocardiography parameters, such as left atrial diameter (LAD), peak E and A of mitralis (E, A), E/A, end-diastolic thickness of ventricular septum (IVST d), end-diastolic thickness of LV posterior wall (PWTd) and left ventricular end-diastolic dimension (LVDd) were obtained from these three groups. Left atrial minimum volume (LAVmin), left atrial pre-atrial contraction volume (LAVp) and left atrial maximum volume (LAVmax) were measured by Simpson’s rule, whereas left atrial active ejection fraction (LAAEF) and left atrial passive ejection fraction (LAPEF) were obtained from calculation. Two-dimensional images were acquired from apical four-chamber view and two-chamber view to store images for offline analysis. The global peak atrial longitudinal strain and strain rate of systolic LV (GLSs, GLSRs) as well as early and late diastolic LV strain rate (GLSRe, GLSRa) curves of LA were acquired in each LA segment from basal segment to top segment of LA by 2D-STE.

Results

Compared with group A, there were no differences between group B and group A (all P > 0.05). The LAAEF and GLSRa were significantly higher in group C compared with those of group A and group B (all P < 0.01). The LAPEF, GLSs, GLSRs and GLSRe were significantly lower in group C compared with those of group A and group B (all P < 0.01).

Conclusions

2D-STE could evaluate the LA function in patients with IDA.

Evaluating the Atrial Myopathy Underlying Atrial Fibrillation: Identifying the Arrhythmogenic and Thrombogenic Substrate

Atrial disease or myopathy forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. Current diagnostic approaches in patients with AF focus on identifying clinical predictors with the evaluation of left atrial size by echocardiography serving as the sole measure specifically evaluating the atrium. Although the atrial substrate underlying AF is likely developing for years before the onset of AF, there is no current evaluation to identify the preclinical atrial myopathy. Atrial fibrosis is 1 component of the atrial substrate that has garnered recent attention based on newer MRI techniques that have been applied to visualize atrial fibrosis in humans with prognostic implications regarding the success of treatment. Advanced ECG signal processing, echocardiographic techniques, and MRI imaging of fibrosis and flow provide up-to-date approaches to evaluate the atrial myopathy underlying AF. Although thromboembolic risk is currently defined by clinical scores, their predictive value is mediocre. Evaluation of stasis via imaging and biomarkers associated with thrombogenesis may provide enhanced approaches to assess risk for stroke in patients with AF. Better delineation of the atrial myopathy that serves as the substrate for AF and thromboembolic complications might improve treatment outcomes. Furthermore, better delineation of the pathophysiologic mechanisms underlying the development of the atrial substrate for AF, particularly in its earlier stages, could help identify blood and imaging biomarkers that could be useful to assess risk for developing new-onset AF and suggest specific pathways that could be targeted for prevention.

Lone atrial fibrillation - an overview

Atrial fibrillation (AF) sometimes develops in younger individuals without any evident cardiac or other disease. To refer to these patients who were considered to have a very favourable prognosis compared with other AF patients, the term 'lone' AF was introduced in 1953. However, there are numerous uncertainties associated with 'lone' AF, including inconsistent entity definitions, considerable variations in the reported prevalence and outcomes, etc. Indeed, increasing evidence suggests a number of often subtle cardiac alterations associated with apparently 'lone' AF, which may have relevant prognostic implications. Hence, 'lone' AF patients comprise a rather heterogeneous cohort, and may have largely variable risk profiles based on the presence (or absence) of overlooked subclinical cardiovascular risk factors or genetically determined subtle alterations at the cellular or molecular level. Whether the implementation of various cardiac imaging techniques, biomarkers and genetic information could improve the prediction of risk for incident AF and risk assessment of 'lone' AF patients, and influence the treatment decisions needs further research. In this review, we summarise the current knowledge on 'lone' AF, highlight the existing inconsistencies in the field and discuss the prognostic and treatment implications of recent insights in 'lone' AF pathophysiology.