Association of Left Atrial Function Index With Late Atrial Fibrillation Recurrence after Catheter Ablation

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

Left atrial function index predicts poor outcomes in acute myocardial infarction patients treated with percutaneous coronary intervention

Background and aims

The left atrial function index (LAFI) is an index that combines the left atrial emptying fraction, adjusted left atrial volume and stroke volume. The prognostic value of LAFI in acute myocardial infarction (AMI) patients treated with percutaneous coronary intervention (PCI) is unknown. This study aims to determine whether LAFI predicts prognosis in AMI patients treated with PCI.

Methods

Patients with newly diagnosed AMI who were treated with PCI at Hunan Provincial People's Hospital from March 2020 to October 2021 were prospectively enrolled. All patients underwent transthoracic echocardiography (TTE) at baseline and follow-up. The endpoint events included rehospitalization due to unstable angina, nonfatal myocardial infarction, rehospitalization due to heart failure and cardiovascular death.

Results

A total of 368 patients with AMI (92 women; mean age, 61.45 ± 11.91 years) were studied with a median follow-up of 14 ± 6.58 months. Sixty-nine patients had endpoint events. Patients who presented with events had a significantly lower LAFI than patients without events (34.25 ± 12.86 vs. 48.38 ± 19.42, P < 0.0001). Multivariate Cox analysis demonstrated that LAFI (HR = 0.97 [95% CI: 0.95; 0.99]; P = 0.012) and the Killip classification (HR = 1.51 [95% CI: 1.03; 2.22]; P = 0.034) were independently predictive of endpoint events. Kaplan-Meier survival curves showed that patients with LAFI ≤ 40.17 cm/ml/m2 had higher events than patients with LAFI > 40.17 cm/ml/m2 (HR = 8.53 [95% CI: 4.74; 15.35]; P < 0.0001).

Conclusion

LAFI is a strong and independent predictor of adverse events and can be used for risk stratification in patients with AMI treated with PCI.

Left atrial function index predicts poor outcome in STEMI patients treated with percutaneous coronary intervention

The prognostic value of the left atrial function index (LAFI) in acute ST segment elevation myocardial infarction (STEMI) patients treated with percutaneous coronary intervention (PCI) is unknown. This study sought to determine whether the LAFI predicts prognosis in STEMI patients treated with PCI. Patients with newly diagnosed STEMI who were treated with PCI in Hunan Provincial People's Hospital from March 2020 to October 2020 were prospectively enrolled. All patients underwent transthoracic echocardiography at baseline and follow-up. The endpoint events included rehospitalization due to unstable angina, nonfatal myocardial infarction, rehospitalization due to heart failure and cardiovascular death. A total of 156 STEMI patients treated with PCI were studied with a median follow-up of 14 months. Forty-eight patients had endpoint events. The LAFI had the highest area under the receiver operating characteristic curve (AUC) predicting the endpoint events, with an AUC of 0.90 (95% CI 0.84-0.94). Multivariate Cox analysis demonstrated that only the LAFI (HR: 0.91, 95% CI 0.87-0.96, P < 0.0001) was independently predictive of endpoint events. Kaplan‒Meier survival curves showed that patients with an LAFI ≤ 42.25 cm/cc/m² had more events than patients with an LAFI > 42.25 cm/cc/m² (HR: 19.15, 95% CI 8.90-41.21, P < 0.001). The LAFI is a strong and independent predictor of events in STEMI patients treated with PCI.

Progress in the Study of the Left Atrial Function Index in Cardiovascular Disease: A Literature Review

Some studies have shown that left ventricular structure and function play an important role in the risk stratification and prognosis of cardiovascular disease. The clinical application of left atrial function in cardiovascular disease has gradually attracted attention in the cardiovascular field. There are many traditional methods to evaluate left atrial function. Left atrial function related indexes measured by echocardiography has been identified as a powerful predictor of cardiovascular disease in recent years, but they have some limitations. The left atrial function index has been found to evaluate left atrial function more effectively than traditional parameters. Furthermore, it is a valuable predictor of the risk stratification and prognosis in patients with clinical cardiovascular disease such as heart failure, atrial fibrillation, hypertension, and coronary heart disease.

A predictive model using left atrial function and B-type natriuretic peptide level in predicting the recurrence of early persistent atrial fibrillation after radiofrequency ablation

Aim

A predictive model using left atrial function indexes obtained by real‐time three‐dimensional echocardiography (RT‐3DE) and the blood B‐type natriuretic peptide (BNP) level was constructed, and its value in predicting recurrence in patients with early persistent atrial fibrillation (AF) after radiofrequency ablation was explored.

Methods

A total of 228 patients with early persistent AF who were scheduled to receive the first circular pulmonary vein ablation (CPVA) were enrolled. Clinical data of patients were collected: (1) The blood BNP level was measured before radiofrequency ablation; (2) RT‐3DE was used to obtain the left atrial (LA) time‐volume curve; (3) The clinical characteristics, BNP level and LA function parameters were compared, and logistic regression was used to construct a prediction model with combined parameters; (4) The receiver operating characteristic (ROC) curve was used to examine the diagnostic efficacy of the model.

Results

(1) 215 patients with early persistent AF completed CPVA and the follow‐up. After 3–6 months of follow‐up, the patients were divided into sinus rhythm group (160 cases) and recurrence group (55 cases); (2) The recurrence group showed higher minimum LA volume index, diastolic ejection index, and preoperative BNP (all p ≤ .001), while the sinus rhythm group exhibited higher expansion index (PI) and left atrial appendage peak emptying velocity (p ≤ .001); (3) In univariate analysis, BNP level had the best diagnostic performance in predicting the recurrence of AF(AUC = 0.703). We constructed a model based on LA function and BNP level to predict the recurrence of persistent AF after CPVA. This combined model was better than BNP alone in predicting the recurrence of persistent AF after CPVA (AUC: 0.814 vs. 0.703, z = 2.224, p = .026).

Conclusion

The combined model of LA function and blood BNP level has good predictive value for the recurrence of early persistent AF after CPVA.

Relations between plasma microRNAs, echocardiographic markers of atrial remodeling, and atrial fibrillation: Data from the Framingham Offspring study

BACKGROUND

Circulating microRNAs may reflect or influence pathological cardiac remodeling and contribute to atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to identify candidate plasma microRNAs that are associated with echocardiographic phenotypes of atrial remodeling, and incident and prevalent AF in a community-based cohort.

METHODS

We analyzed left atrial function index (LAFI) of 1788 Framingham Offspring 8 participants. We quantified expression of 339 plasma microRNAs. We examined associations between microRNA levels with LAFI and prevalent and incident AF. We constructed pathway analysis of microRNAs' predicted gene targets to identify molecular processes involved in adverse atrial remodeling in AF.

RESULTS

The mean age of the participants was 66 ± 9 years, and 54% were women. Five percent of participants had prevalent AF at the initial examination and 9% (n = 157) developed AF over a median 8.6 years of follow-up (IQR 8.1-9.2 years). Plasma microRNAs were associated with LAFI (N = 73, p<0.0001). Six of these plasma microRNAs were significantly associated with incident AF, including 4 also associated with prevalent AF (microRNAs 106b, 26a-5p, 484, 20a-5p). These microRNAs are predicted to regulate genes involved in cardiac hypertrophy, inflammation, and myocardial fibrosis.

CONCLUSIONS

Circulating microRNAs 106b, 26a-5p, 484, 20a-5p are associated with atrial remodeling and AF.

Left atrial structure and function predictors of recurrent fibrillation after catheter ablation: a systematic review and meta-analysis

BACKGROUND

Catheter ablation (CA) has become a conventional treatment for atrial fibrillation (AF), but remains with high recurrence rate. The aim of this meta-analysis was to determine left atrial (LA) structure and function indices that predict recurrence of AF.

METHODS

We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to September 2017 in order to select clinical trials and observational studies which reported echocardiographic predictors of AF recurrence after CA. Eighty-five articles with a total of 16 126 patients were finally included.

RESULTS

The pooled analysis showed that after a follow-up period of 21 ± 12 months, patients with AF recurrence had larger LA diameter with weighted mean difference (WMD: 2·99 ([95% CI 2·50-3·47], P<0·001), larger LA volume index (LAVI) maximal and LAVI minimal (P<0·0001 for both), larger LA area (P<0·0001), lower LA strain (P<0·0001) and lower LA total emptying fraction (LA EF) (P<0·0001) compared with those without AF recurrence. The most powerful LA predictors (in accuracy order) of AF recurrence were as follows: LA strain <19% (OR: 3·1[95% CI, -1.3-10·4], P<0·0001), followed by LA diameter ≥50 mm (OR: 2·75, [95% CI 1·66-4·56,] P<0·0001), and LAVmax >150 ml (OR: 2·25, [95% CI, 1.1-5·6], P = 0·0002).

CONCLUSIONS

Based on this meta-analysis results, a dilated left atrium with diameter more than 50 mm and volume above 150 ml or myocardial strain below 19% reflect an unstable LA that is unlikely to hold sinus rhythm after catheter ablation for atrial fibrillation.

Micro-RNAs Are Related to Epicardial Adipose Tissue in Participants With Atrial Fibrillation: Data From the MiRhythm Study

Introduction: Epicardial adipose tissue (EAT) has been linked to incidence and recurrence of atrial fibrillation (AF), but the underlying mechanisms that mediate this association remain unclear. Circulating microRNAs (miRNAs) contribute to the regulation of gene expression in cardiovascular diseases, including AF. Thus, we sought to test the hypothesis that circulating miRNAs relate to burden of EAT.

Methods: We examined the plasma miRNA profiles of 91 participants from the miRhythm study, an ongoing study examining associations between miRNA and AF. We quantified plasma expression of 86 unique miRNAs commonly expressed in cardiomyocytes using quantitative reverse transcriptase polymerase chain reaction (qPCR). From computed tomography, we used validated methods to quantify the EAT area surrounding the left atrium (LA) and indexed it to body surface area (BSA) to calculate indexed LA EAT (iLAEAT). Participants were divided into tertiles of iLAEAT to identify associations with unique miRNAs. We performed logistic regression analyses adjusting for factors associated with AF to examine relations between iLAEAT and miRNA. We performed further bioinformatics analysis of miRNA predicted target genes to identify potential molecular pathways are regulated by the miRNAs.

Results: The mean age of the participants was 59 ± 9, 35% were women, and 97% were Caucasian. Participants in the highest tertile of iLAEAT were more likely to have hypertension, heart failure, and thick posterior walls. In regression analyses, we found that miRNAs 155-5p (p < 0.001) and 302a-3p (p < 0.001) were significantly associated with iLAEAT in patients with AF. The predicted targets of the miRNAs identified were implicated in the regulation of cardiac hypertrophy, adipogenesis, interleukin-8 (IL-8), and nerve growth factor (NGF) signaling.

Conclusion: miRNA as well as EAT have previously been linked to AF. Our finding that iLAEAT and miRNAs 155-5p and 302a-3p are associated suggest a possible direct link to between these entities in the development and maintenance of AF. Further research is needed to study causal relationships between these biomarkers.

Hemodynamic impact of percutaneous left atrial appendage closure in patients with paroxysmal atrial fibrillation

PURPOSE

Percutaneous left atrial appendage (LAA) closure has become a valid alternative to anticoagulation therapy for the prevention of thromboembolic events in patients with atrial fibrillation (AF). However, scarce data exist on the impact of LAA closure on left atrial and ventricular function. We sought to assess the acute hemodynamic changes associated with percutaneous LAA closure in patients with paroxysmal AF.

METHODS

The study population consisted of 31 patients (mean age 73 ± 10 years; 49% women) with paroxysmal AF who underwent successful percutaneous LAA closure. All patients were in sinus rhythm and underwent 2D transthoracic echocardiography at baseline and the day after the procedure. A subset of 14 patients underwent preprocedural cardiac computed tomography (CT) with 3D LA and LAA reconstruction.

RESULTS

Left ventricular systolic function parameters and LA volumetric indexes remained unchanged after the procedure. No significant changes in left ventricular stroke volume (72.4 ± 16.0 vs. 73.3 ± 15.7 mL, p = 0.55) or LA stroke volume (total 15.6 ± 4.2 vs. 14.6 ± 4.2 mL, p = 0.21; passive 9.0 ± 2.8 vs. 8.3 ± 2.6 mL, p = 0.31; active 10.3 ± 5.6 vs. 10.0 ± 6.4 mL, p = 0.72) occurred following LAA closure. Mean ratio of LAA to LA volume by 3D CT was 10.2 ± 2.3%. No correlation was found between LAA/LA ratio and changes in LA stroke volume (r = 0.35, p = 0.22) or left ventricular stroke volume (r = 0.28, p = 0.33).

CONCLUSIONS

The LAA accounts for about 10% of the total LA volume, but percutaneous LAA closure did not translate into any significant changes in LA and left ventricular function.

Association of Left Atrial Function Index with Atrial Fibrillation and Cardiovascular Disease: The Framingham Offspring Study

BACKGROUND

Left atrial (LA) size, a marker of atrial structural remodeling, is associated with increased risk for atrial fibrillation (AF) and cardiovascular disease (CVD). LA function may also relate to AF and CVD, irrespective of LA structure. We tested the hypothesis that LA function index (LAFI), an echocardiographic index of LA structure and function, may better characterize adverse LA remodeling and predict incident AF and CVD than existing measures.

METHODS AND RESULTS

In 1786 Framingham Offspring Study eighth examination participants (mean age, 66±9 years; 53% women), we related LA diameter and LAFI (derived from the LA emptying fraction, left ventricular outflow tract velocity time integral, and indexed maximal LA volume) to incidence of AF and CVD on follow-up. Over a median follow-up of 8.3 years (range, 7.5-9.1 years), 145 participants developed AF and 139 developed CVD. Mean LAFI was 34.5±12.7. In adjusted Cox regression models, lower LAFI was associated with higher risk of incident AF (hazard ratio=3.83, 95% confidence interval=2.23-6.59, lowest [Q1] compared with highest [Q4] LAFI quartile) and over 2-fold higher risk of incident CVD (hazard ratio=2.20, 95% confidence interval=1.32-3.68, Q1 versus Q4). Addition of LAFI, indexed maximum LA volume, or LA diameter to prediction models for AF or CVD did not significantly improve model discrimination for either outcome.

CONCLUSIONS

In our prospective investigation of a moderate-sized community-based sample, LAFI, a composite measure of LA size and function, was associated with incident AF and CVD. Addition of LAFI to the risk prediction models for AF or CVD, however, did not significantly improve their performance.

Clinical and Echocardiographic Correlates of Left Atrial Function Index: The Framingham Offspring Study

BACKGROUND

Left atrial (LA) remodeling is a predictor of cardiovascular disease (CVD). We performed measurement of the LA function index (LAFI), a composite measure of LA structure and function, in a community-based cohort and here report the distribution and cross-sectional correlates of LAFI.

METHODS

In 1,719 Framingham Offspring Study participants (54% women, mean age 66 ± 9 years), we derived LAFI from the LA emptying fraction, left ventricular (LV) outflow tract velocity time integral, and indexed maximal LA volume. We used multivariable linear regression to assess the clinical and echocardiographic correlates of LAFI adjusting for age, sex, anthropometric measurements, and CVD risk factors.

RESULTS

The average LAFI was 35.2 ± 12.1. Overall, LAFI declined with advancing age (β = -0.27, P < .001). LAFI was significantly higher (37.5 ± 11.6) in a subgroup of participants free of CVD and CVD risk factors compared with those with either of these conditions (34.5 ± 12.2). In multivariable models, LAFI was inversely related to antihypertensive use (β = -1.26, P = .038), prevalent atrial fibrillation (β = -4.46, P = .001), heart failure (β = -5.86, P = .008), and coronary artery disease (β = -2.01, P = .046). In models adjusting for echocardiographic variables, LAFI was directly related to LV ejection fraction (β = 14.84, P < .001) and inversely related to LV volume (β = -7.03, P < .001).

CONCLUSIONS

LAFI was inversely associated with antihypertensive use and prevalent CVD and was related to established echocardiographic traits of LV remodeling. Our results offer normative ranges for LAFI in a white community-based sample and suggest that LAFI represents a marker of pathological atrial remodeling.

Changes in Left Atrial Transport Function in Patients Who Maintained Sinus Rhythm After Successful Radiofrequency Catheter Ablation for Atrial Fibrillation: A 1-Year Follow-Up Multislice Computed Tomography Study

BACKGROUND

Functional remodeling of left atrium (LA) after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been fully elucidated. This study aimed to determine the impact of RFCA on LA transport function in patients who maintained sinus rhythm (SR) after AF ablation.

METHODS AND RESULTS

A total of 96 patients (paroxysmal AF [PAF] = 52) who maintained SR during 1 year after AF ablation were enrolled. Multislice computed tomography was performed to determine LA volume (LAV) and LA emptying fraction (LAEF) at pre-RFCA and 1-year post-RFCA. Creatine kinase-MB (CK-MB) and troponin-T levels were analyzed 1-day post-RFCA. At 1-year post-RFCA, mean LAV and LAEF decreased in overall patients. Based on LAEF change (ΔLAEF) cutoff of 5.0%, LAEF reduced in 41 patients (worsened group) and improved or showed no change in 55 patients (preserved group). Compared with preserved group, worsened group had a higher proportion of PAF, higher levels of CK-MB and troponin-T, and additional LA ablation. ΔLAEF was inversely correlated with CK-MB and troponin-T levels. Subgroup analysis showed that LAEF significantly decreased in PAF patients who underwent additional LA ablation. Multivariate analysis revealed that high baseline LAEF and additional LA ablation were independent predictors for worsened LAEF.

CONCLUSIONS

Although SR was maintained for 1 year after AF ablation, LAEF as well as LAV decreased. The extent of LAEF deterioration was significantly associated with the amount of iatrogenic myocardial damage. Our data indicate that extensive atrial ablation may lead to LA functional deterioration, especially in patients with PAF.