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

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

Pre-procedural Stratification by the Endothelial Function in Patients with Heart Failure Undergoing Atrial Fibrillation Ablation

BACKGROUND

Endothelial dysfunction (ED), a well-established risk marker of cardiovascular events, is associated with heart failure (HF) and atrial fibrillation (AF). Its relationship with cardiovascular events in patients with HF undergoing AF ablation remains unclear. We aimed to elucidate the association between ED and the outcomes after AF ablation in patients with HF.

METHODS

This prospective cohort study included patients with HF who underwent an endothelial function assessment using the peripheral vascular reactive hyperemia index (RHI) before first-time AF ablation. We defined AF recurrence according to the following types: the conventional form (AF≥30 seconds) and persistent form (requiring cardioversion). An RHI<2.1 indicated ED. Those with and without ED were compared in terms of the 3-year incidence of AF recurrence and cardiovascular events after AF ablation.

RESULTS

Among 421 patients with HF (69 ± 9 years and 38% females), 343 (81.5%) had ED. Although the incidence of the conventional form of AF recurrence was similar between the groups, that of the persistent form was significantly higher in the ED group (25.7% vs. 15.3%, log-rank P = 0.028). The ED group also had a significantly higher rate of cardiovascular events (14.8% vs. 3.6%, log-rank P = 0.028). Pre-procedural ED was identified as an independent predictor of a persistent form of AF recurrence (adjusted hazard ratio [HR] 2.31, 95% confidence interval [CI] 1.05-5.07, P = 0.037) and that of cardiovascular events (adjusted HR 4.21, 95% CI 1.02-17.5, P = 0.048), respectively.

CONCLUSIONS

The endothelial function assessment enabled the risk stratification of clinically problematic outcomes after AF ablation in patients with HF.

Impact of rs1805127 and rs55742440 Variants on Atrial Remodeling in Hypertrophic Cardiomyopathy Patients with Atrial Fibrillation: A Romanian Cohort Study

Atrial fibrillation (AFib) is characterized by a complex genetic component. We aimed to investigate the association between variations in genes related to cardiac ion handling and AFib in a cohort of Romanian patients with hypertrophic cardiomyopathy (HCM). Forty-five unrelated probands with HCM were genotyped by targeted next-generation sequencing (NGS) for 24 genes associated with cardiac ion homeostasis. Subsequently, the study cohort was divided into two groups based on the presence (AFib+) or absence (AFiB-) of AFib detected during ECG monitoring. We identified two polymorphisms (rs1805127 located in KCNE1 and rs55742440 located in SCN1B) linked to AFib susceptibility. In AFib+, rs1805127 was associated with increased indexed left atrial (LA) maximal volume (LAVmax) (58.42 ± 21 mL/m2 vs. 32.54 ± 6.47 mL/m2, p < 0.001) and impaired LA strain reservoir (LASr) (13.3 ± 7.5% vs. 24.4 ± 6.8%, p < 0.05) compared to those without respective variants. The rs55742440 allele was less frequent in patients with AFib+ (12 out of 25, 48%) compared to those without arrhythmia (15 out of 20, 75%, p = 0.05). Also, AFib+ rs55742440 carriers had significantly lower LAVmax compared to those who were genotype negative. Among patients with HCM and AFib+, the rs1805127 variant was accompanied by pronounced LA remodeling, whereas rs55742440's presence was related to a milder LA enlargement.

Effects of Rhythm Control for Atrial Fibrillation on Cardiac Remodeling and Valvular Regurgitation in Patients with Heart Failure

PURPOSE

Previous studies investigating cardiac remodeling and functional regurgitation of rhythm control for atrial fibrillation (AF) in heart failure (HF) are limited. Therefore, this study aimed to evaluate the impact of rhythm control for AF on cardiac remodeling and functional regurgitation in the spectrum of HF. Its effect on prognosis was explored.

METHODS

According to the treatment strategies of AF, the cohort was classified into the rhythm control and rate control groups. To further detect the implications of rhythm control on cardiac remodeling, functional regurgitation, and outcomes in HF subtypes, patients were further divided into HF with reduced ejection fraction (HFrEF), HF with mildly reduced ejection fraction, and HF with preserved ejection fraction (HFpEF) subgroups.

RESULTS

A total of 828 patients were enrolled, with 307 patients in the rhythm control group and 521 patients in the rate control group. Over a median follow-up time of 3.8 years, patients with rhythm control treatments experienced improvements in biatrial structure parameters, left ventricular ejection fraction, and functional regurgitation (mitral and tricuspid regurgitation) compared with rate control treatment (p < 0.05). Cox regression analysis demonstrated that rhythm control reduced the risks of all-cause mortality (HR 0.436 [95% CI, 0.218-0.871], p = 0.019) in HFpEF and HF-related admissions in HFrEF (HR 0.500 [95% CI, 0.330-0.757], p = 0.001) and HFpEF (HR 0.541 [95% CI, 0.407-0.720], p < 0.001); these associations were similar after adjusting for multiple confounders.

CONCLUSIONS

Rhythm control therapy can be considered an appropriate treatment strategy for the management of AF in HF to improve cardiac remodeling, functional regurgitation, and prognosis.

Incremental predictive utility of a radiomics signature in a nomogram for the recurrence of atrial fibrillation

Background

Recurrence of atrial fibrillation (AF) after catheter ablation (CA) remains a challenge today. Although it is believed that evaluating the structural and functional remodeling of the left atrium (LA) may be helpful in predicting AF recurrence, there is a lack of consensus on prediction accuracy. Ultrasound-based radiomics is currently receiving increasing attention because it might aid in the diagnosis and prognosis prediction of AF recurrence. However, research on LA ultrasound radiomics is limited.

Objective

We aim to investigate the incremental predictive utility of LA radiomics and construct a radiomics nomogram to preoperatively predict AF recurrence following CA.

Methods

A training cohort of 232 AF patients was designed for nomogram construction, while a validation cohort (n = 100) served as the model performance test. AF recurrence during a follow-up period of 3-12 months was defined as the endpoint. The radiomics features related to AF recurrence were extracted and selected to create the radiomics score (rad score). These rad scores, along with other morphological and functional indicators for AF recurrence, were included in the multivariate Cox analysis to establish a nomogram for the prediction of the likelihood of AF recurrence within 1 year following CA.

Results

In the training and validation cohorts, AF recurrence rates accounted for 32.3% (75/232) and 25.0% (25/100), respectively. We extracted seven types of radiomics features associated with AF recurrence from apical four-chamber view echocardiography images and established a rad score for each patient. The radiomics nomogram was built with the rad score, AF type, left atrial appendage emptying flow velocity, and peak atrial longitudinal strain. It outperformed the nomogram building without the rad score in terms of the predictive efficacy of CA outcome and showed favorable performance in both cohorts.

Conclusion

We revealed the incremental utility of a radiomics signature in the prediction of AF recurrence and preliminarily developed and validated a radiomics nomogram for identifying patients who were at high risk of post-CA recurrence, which contributed to an appropriate management strategy for AF.

Effect of Insulin Resistance on Recurrence after Radiofrequency Catheter Ablation in Patients with Atrial Fibrillation

BACKGROUND

Whether there are many risk factors for recurrence of atrial fibrillation (AF) after ablation is unclear. The aim of this study was to investigate the relationship between insulin resistance (IR) and AF recurrence in patients without diabetes who underwent catheter ablation.

METHODS

This retrospective study included patients who underwent AF ablation between 2018 and 2019 at the First Affiliated Hospital of Zhengzhou University. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated, and a value of ≥2.69 was defined as IR. The patients were divided into two groups (group 1 HOMA-IR < 2.69, n = 163; group 2 HOMA-IR ≥ 2.69, n = 69). AF recurrence was defined as the occurrence of atrial arrhythmias of more than 30 s after the first 3 months. Univariate and multivariable Cox regression models were used to analyse the risk of AF recurrence.

RESULTS

Overall, 232 patients were enrolled (mean age, 59.9 ± 10.2 years old; female, 37.5%; paroxysmal AF, 71.6%). We found that dyslipidaemia, antiarrhythmic drug use, fasting blood glucose and fasting insulin were significantly higher in the IR group (P < 0.05). During the follow-up 1 year after ablation, 62 (26.7%) patients experienced AF recurrence. After adjusting for traditional risk factors, multivariable analysis showed that the HOMA-IR value (HR 1.259, 95% CI 1.086-1.460, P = 0.002) and left atrial diameter (LAD; HR 1.043, 95% CI 1.005-1.083, P = 0.026) were independently associated with AF recurrence.

CONCLUSIONS

The present results provide evidence that IR patients are more likely to experience AF recurrence. Improving IR status may be a potential target for reducing the postoperative recurrence rate.

Development and Validation of a Novel Prognostic Tool to Predict Recurrence of Paroxysmal Atrial Fibrillation after the First-Time Catheter Ablation: A Retrospective Cohort Study

There is no gold standard to tell frustrating outcomes after the catheter ablation of paroxysmal atrial fibrillation (PAF). The study aims to construct a prognostic tool. We retrospectively analyzed 315 patients with PAF who underwent first-time ablation at the Second Xiangya Hospital of Central South University. The endpoint was identified as any documented relapse of atrial tachyarrhythmia lasting longer than 30 s after the three-month blanking period. Univariate Cox regression analyzed eleven preablation parameters, followed by two supervised machine learning algorithms and stepwise regression to construct a nomogram internally validated. Five factors related to ablation failure were as follows: female sex, left atrial appendage emptying flow velocity ≤31 cm/s, estimated glomerular filtration rate <65.8 mL/(min·1.73 m²), P wave duration in lead aVF ≥ 120 ms, and that in lead V1 ≥ 100 ms, which constructed a nomogram. It was correlated with the CHA₂DS₂-VASc score but outperformed the latter evidently in discrimination and clinical utility, not to mention its robust performances in goodness-of-fit and calibration. In addition, the nomogram-based risk stratification could effectively separate ablation outcomes. Patients at risk of relapse after PAF ablation can be recognized at baseline using the proposed five-factor nomogram.

Expert proposal to characterize cardiac diseases with normal or preserved left ventricular ejection fraction and symptoms of heart failure by comprehensive echocardiography

Currently, the term "heart failure with preserved left ventricular ejection fraction (HFpEF)" is based on echocardiographic parameters and clinical symptoms combined with elevated or normal levels of natriuretic peptides. Thus, "HFpEF" as a diagnosis subsumes multiple pathophysiological entities making a uniform management plan for "HFpEF" impossible. Therefore, a more specific characterization of the underlying cardiac pathologies in patients with preserved ejection fraction and symptoms of heart failure is mandatory. The present proposal seeks to offer practical support by a standardized echocardiographic workflow to characterize specific diagnostic entities associated with "HFpEF". It focuses on morphological and functional cardiac phenotypes characterized by echocardiography in patients with normal or preserved left ventricular ejection fraction (LVEF). The proposal discusses methodological issues to clarify why and when echocardiography is helpful to improve the diagnosis. Thus, the proposal addresses a systematic echocardiographic approach using a feasible algorithm with weighting criteria for interpretation of echocardiographic parameters related to patients with preserved ejection fraction and symptoms of heart failure. The authors consciously do not use the diagnosis "HFpEF" to avoid misunderstandings. Central illustration: Scheme illustrating the characteristic echocardiographic phenotypes and their combinations in patients with "HFpEF" symptoms with respect to the respective cardiac pathology and pathophysiology as well as the underlying typical disease.

Role of Cardiovascular Magnetic Resonance in the Management of Atrial Fibrillation: A Review

Atrial fibrillation (AF) is the most common arrhythmia, and its prevalence is growing with time. Since the introduction of catheter ablation procedures for the treatment of AF, cardiovascular magnetic resonance (CMR) has had an increasingly important role for the treatment of this pathology both in clinical practice and as a research tool to provide insight into the arrhythmic substrate. The most common applications of CMR for AF catheter ablation are the angiographic study of the pulmonary veins, the sizing of the left atrium (LA), and the evaluation of the left atrial appendage (LAA) for stroke risk assessment. Moreover, CMR may provide useful information about esophageal anatomical relationship to LA to prevent thermal injuries during ablation procedures. The use of late gadolinium enhancement (LGE) imaging allows to evaluate the burden of atrial fibrosis before the ablation procedure and to assess procedural induced scarring. Recently, the possibility to assess atrial function, strain, and the burden of cardiac adipose tissue with CMR has provided more elements for risk stratification and clinical decision making in the setting of catheter ablation planning of AF. The purpose of this review is to provide a comprehensive overview of the potential applications of CMR in the workup of ablation procedures for atrial fibrillation.

Left atrial appendage function and structure predictors of recurrent atrial fibrillation after catheter ablation: A meta-analysis of observational studies

Background

The results of studies evaluating the left atrial appendage (LAA) function and structure as predictors of atrial fibrillation (AF) recurrence after catheter ablation (CA) are contradictory. Therefore, we performed a meta-analysis to assess whether the LAA function and structure can predict the recurrence of AF after CA.

Methods

The PubMed, EMBASE, Web of Science, and Cochrane library databases were used to conduct a comprehensive literature search. Finally, 37 studies encompassing 11 LAA parameters were included in this meta-analysis.

Results

Compared with those in the non-recurrence group, the recurrence group had increased LAA volume (SMD 0.53, 95% CI [0.36, 0.71] p < 0.00001), LAA volume index, LAA orifice area, and LAA orifice short/long axis and decreased LAA emptying flow velocity (SMD -0.54, 95% CI [-0.68, -0.40], P < 0.00001), LAA filling flow velocity, and LAA ejection fraction, while there was no significant difference in LAA morphology or LAA depth.

Conclusion

Large LAA structure of pre-ablation (LAA volume, orifice area, orifice long/short axis, and volume index) and decreased LAA function of pre-ablation (LAA emptying flow velocity, filling flow velocity, ejection fraction, and LASEC) increase the odds of AF recurrence after CA.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42022324533].

Clinical utility of left atrial strain in predicting atrial fibrillation recurrence after catheter ablation: An up-to-date review

Rhythm control is the core part of the integrated management of atrial fibrillation (AF), especially in the early stages. Despite advances in catheter ablation (CA), the recurrence rate of AF after CA remains high. As a result, stratification and early management of AF recurrence after CA are critical. Currently, predictors of recurrence of AF after CA are mostly based on dysfunction caused by structural remodeling, apart from traditional risk factors. Atrial strain is a recently developed important parameter for detecting the deformability of atrial myocardium during the cardiac cycle prior to atrial remodeling. Although there is only preliminary evidence, atrial strain is still a promising parameter in predicting the recurrence of AF after CA at an early stage. This review focuses on the evaluation of atrial strain, the current applications of atrial strain in assessing atrial function, and predicting the recurrence of AF after CA. We summarize the contents related as follows: (1) CA for rhythm control in AF; (2) Evaluation methods of atrial strain; (3) Atrial strain in the remodeling and reverse remodeling of AF; and (4) Clinical applications of atrial strain in predicting the recurrence of AF after CA. Although there is accumulating evidence on the role of decreased atrial strain in the early prediction of AF recurrence, atrial strain is limited in clinical practice for lacking exact cut-off values and difficulty in distinguishing specific function phases of the atrium. More research is needed in the future to add strength to the early prediction value of atrial strain in AF recurrences.

Effect of radiofrequency catheter ablation on left atrial structure and function in patients with different types of atrial fibrillation

Radiofrequency catheter ablation (RFCA) is widely used to treat atrial fibrillation (AF), but its effect on left atrial (LA) remodeling in patients with AF is not completely clarified. Few studies have reported the changes in structure and function of the left atrium in patients with different types of AF after RFCA. To analyze the effect of RFCA on the LA structure and function in patients with nonvalvular paroxysmal AF, persistent AF and long-standing persistent AF (LSPAF). RFCA was performed in 180 patients with paroxysmal AF, persistent AF and LSPAF. The changes of LA structure and function in echocardiogram and speckle-tracking echocardiography findings were compared before the procedure, and at 1, 2, 3, 4 weeks, and 2, 3, 6, and 9–12 months after the procedure. There were 60 patients in the paroxysmal AF group, 60 in the persistent AF group and 60 patients in LSPAF group. The pre-procedure LA diameter and volume were smaller in the paroxysmal AF group than persistent AF and LSPAF group. There was no significant change of in the LA structure and function in the paroxysmal AF group within 1 year. In the persistent AF and LSPAF groups, LA structure (anteroposterior diameter, LA volume) significantly decreased, but remained larger than that in paroxysmal AF group. In persistent and LSPAF, function (LA ejection fraction, strain, strain rate) increased significantly within 1 week, then gradually increased. RFCA improved the LA structure and function and resulted in heart reverse remodeling, especially for persistent AF and LSPAF.

Left atrial contractile strain predicts recurrence of atrial tachyarrhythmia after catheter ablation

BACKGROUND

Despite improvement in treatment strategies of atrial fibrillation (AF), a considerable number of patients still experience recurrence of atrial tachyarrhythmia (ATA) following catheter ablation (CA). This study aimed to investigate the prognostic value of left atrial (LA) deformation analysis in a large group of patients undergoing CA for AF.

METHODS

This study included 678 patients with AF. Echocardiography including two-dimensional speckle tracking echocardiography (2DSTE) was performed in all patients prior to CA. Logistic regression analysis was used to assess the association between ATA recurrence and LA strain during reservoir phase (LASr), LA strain during contraction phase (LASct), and LA strain during conduit phase (LAScd).

RESULTS

During one-year follow-up, 274 (40%) experienced ATA recurrence. Median age of the included study population was 63.2 years (IQR: 55.5, 69.5) and 485 (72%) were male. Patients with recurrence had lower LASr (22.6% vs. 25.1%, p = 0.001) and LASct (10.7% vs. 12.4%, p < 0.001). No difference in LAScd was observed. After adjusting for potential clinical and echocardiographic confounders LASr (OR = 1.04, CI95% [1.01; 1.07], p = 0.015, per 1% decrease) and LASct (OR = 1.06, CI95% [1.02; 1.11], p = 0.007, per 1% decrease) remained independent predictors of recurrence. However, in patients with a normal-sized LA (LA volume index<34 mL/m²), only LASct remained an independent predictor of recurrence (OR = 1.07, CI95% [1.01; 1.12], p = 0.012, per 1% decrease).

CONCLUSION

In patients undergoing CA for AF, LA deformation analysis by 2DSTE could be of use in risk stratification in clinical practice regarding ATA recurrence, even in patients with a normal-sized LA.

Left atrial booster-pump function as a predictive parameter for atrial fibrillation in patients with severely dilated left atrium

BACKGROUND

Left atrial (LA) dimension ≥50 mm had approximately four times the risk of developing atrial fibrillation (AF). The aim of this study was to investigate whether the application of clinical and echocardiographic parameters could differentiate between the patients having severely dilated left atrium with and without AF.

METHODS

This retrospective cross-sectional study enrolled consecutive patients with LA dimension ≥50 mm and divided them into three groups: no AF (no-AF), paroxysmal AF (PAF) and non-paroxysmal AF (non-PAF) groups. For PAF and non-PAF groups, all patients underwent radiofrequency ablation, and the echocardiographic parameters were obtained on the next day after ablation.

RESULTS

Our study population comprised 160 patients, including 80, 53, and 27 patients in the non-AF, PAF and non-PAF groups, respectively. The no-AF group had a significantly higher body mass index (kg/m2) (29.31±6.27, 27.58±4.12 and 26.57±2.81, P=0.01), and a higher prevalence of diabetes mellitus (DM) [31 (38.80%), 13 (25.00%) and 4 (14.80%), P=0.01] and hypertension [67 (83.80%), 34 (65.40%), and 19 (70.40%), P=0.04], but a lower prevalence of rheumatic heart disease (RHD) [3 (3.80%), 6 (11.50%) and 5 (18.50%), P=0.02] and sick sinus syndrome [0 (0.00%), 6 (11.50%) and 4 (14.80%), P=0.045]. Echocardiographic studies showed that the non-AF group had significantly smaller LA minimal volume index (24.89±9.74, 34.06±19.38 and 42.83±17.44 mL/m2, P<0.01), higher LA emptying fraction (51.99%±13.97%, 38.40%±15.96% and 33.89%±10.73%, P<0.01), longitudinal strain (23.87%±7.72%, 17.11%±8.52% and 12.38%±4.28%, P<0.01) and strain rate than the AF groups. The multivariate analysis showed that the late diastolic component of LA strain rate was the only independent factor associated with the presence of AF (odds ratio, 21.69; 95% CI, 9.77-48.13, P<0.01).

CONCLUSIONS

LA function plays an important role in the absence of AF in patients with LA dimension ≥50 mm; the late diastolic component of LA strain rate was the only independent variable on multivariate analysis.

Impact of left atrial geometric remodeling on late atrial fibrillation recurrence after catheter ablation

AIMS

To quantitatively investigate the impact of left atrial geometric remodeling on atrial fibrillation recurrence after catheter ablation.

METHODS

A retrospective analysis of 105 patients with atrial fibrillation who underwent coronary computed tomographic angiography before catheter ablation. Risk factors for atrial fibrillation recurrence were identified by multivariable logistic regression analysis and used to create a nomogram.

RESULTS

After at least 12 months of follow-up, 30 patients (29%) developed recurrent atrial fibrillation. Patients with recurrence had higher left atrial volume, left atrial sphericity, and lower left atrial ejection fraction (LAEF) (P < 0.05). There was no significant difference in asymmetry index between the two groups (P = 0.121). Multivariable regression analysis showed that left atrial minimal volume index (LAVImin) [odds ratio (OR): 1.026, 95% confidence interval (CI): 1.002-1.050, P = 0.034], left atrial sphericity (OR: 1.222, 95% CI: 1.040-1.435, P = 0.015) and CHADS2 score (OR: 1.511, 95% CI: 1.024-2.229, P = 0.038) were independent predictors of atrial fibrillation recurrence. The combined model of the left atrial sphericity to the LAVImin substantially increased the predictive power for atrial fibrillation recurrence [area under the curve (AUC) = 0.736, 95% CI: 0.627-0.844, P < 0.001], with a sensitivity of 80% and a specificity of 61%. A nomogram was generated based on the contribution weights of the risk factors; the AUC was 0.772 (95% CI: 0.670-0.875) and had good internal validity.

CONCLUSION

The CHADS2 score, left atrial sphericity, and LAVImin were significant and independent predictors of atrial fibrillation recurrence after catheter ablation. Furthermore, the nomogram had a better predictive capacity for atrial fibrillation recurrence.

The prognostic significance of left atrial appendage peak flow velocity in the recurrence of persistent atrial fibrillation following first radiofrequency catheter ablation

Background

Atrial fibrillation (AF) relapse following radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (PeAF) continues to be a concern. This study establishes a connection between left atrial appendage peak flow velocity (LAAV) and recurrence of AF in individuals having PeAF following first RFCA.

Methods

We retrospectively studied 164 successive PeAF patients who had first RFCA between January 2018 and December 2019. Before the ablation, the LAAV was recorded using transesophageal echocardiography (TEE). The demographic and clinical data of the individuals were gathered. Participants were monitored at regular intervals to monitor for recurrence of AF. We employed Cox proportional hazards regression to determine if LAAV, as well as other clinical indicators, were predictive of AF recurrence in follow-up.

Results

In this study, AF relapse was seen in 43 patients (26.2%) following a median follow-up of 15 [interquartile range (IQR): 12–18] months. It was shown that the LAAV was decreased in individuals who had recurrences of AF (0.36±0.05 vs. 0.45±0.17 m/s, P=0.004). Using Kaplan-Meier analysis, it was discovered that the low LAAV (0.37 m/s) group had a poorer event-free survival rate compared to the high LAAV (>0.37 m/s) group (17.6 vs. 21.2 months, log-rank P=0.002) group. Based on the results of the multivariate Cox regression analysis, a LAAV of fewer than 0.37 m/s [hazard ratio (HR): 2.32; 95% confidence interval (CI): 1.177–4.227; P=0.014] was shown to be an independent predictor of AF recurrence following RFCA.

Conclusions

A low LAAV is associated with AF relapse, and it is a predictor of AF relapse following the first RFCA for PeAF. This discovery may be useful in the optimization of treatment strategies and the care of patients with PeAF.

The role of left atrial peak systolic strain in atrial fibrillation recurrence after catheter ablation. A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis was performed to assess the prognostic role of left atrial peak systolic longitudinal strain (LA-PLSsys) as a predictor of atrial fibrillation (AF) recurrence after catheter ablation.

METHODS

We systematically searched major electronic databases and grey literature for studies assessing the role of pre-ablation LA-PLSsys, measured in at least two segments, in post-ablation AF recurrence, after a follow-up period of at least 6 months.

RESULTS

Seventeen eligible studies were included, resulting in 1704 patients (68.6% men) with a pooled mean age of 59.9 ± 10.6 years, 65.9% with paroxysmal AF. Recurrence occurred in 32.7% of patients. Those without recurrence had significantly higher LA-PLSsys (pooled mean ± SD: 22.22 ± 10.64%, weighted mean difference: 5.43%, 95%CI: 4.03-6.84%, I²: 82.7%). Subgroup analysis revealed that the methodology used (echocardiographic view and segments assessed), was a significant source of heterogeneity (p = 0.02). Meta-regression analysis demonstrated that the effect size was inversely related to the baseline LA volume index (p = 0.004), while concerns are also raised about patients with extremely high/low pre-ablation LA strain.

CONCLUSIONS

Pre-ablation LA-PLSsys seems to be a useful predictor of post-ablation AF recurrence, that could optimise patients selection. Nevertheless, the substantial heterogeneity that was noted may limit its clinical use. Further investigation using a uniform methodological assessment technique is required to derive a reference range, with adequate positive and negative predictive value for recurrence.

Prevention of Pathological Atrial Remodeling and Atrial Fibrillation: JACC State-of-the-Art Review

Atrial enlargement in response to pathological stimuli (e.g., hypertension, mitral valve disease) and physiological stimuli (exercise, pregnancy) can be comparable in magnitude, but the diseased enlarged atria is associated with complications such as atrial fibrillation (AF), whereas physiological atrial enlargement is not. Pathological atrial enlargement and AF is also observed in a small percentage of athletes undergoing extreme/intense endurance sport and pregnant women with preeclampsia. Differences between physiological and pathological atrial enlargement and underlying mechanisms are poorly understood. This review describes human and animal studies characterizing atrial enlargement under physiological and pathological conditions and highlights key knowledge gaps and clinical challenges, including: 1) the limited ability of atria to reverse remodel; and 2) distinguishing physiological and pathological enlargement via imaging/biomarkers. Finally, this review discusses how targeting distinct molecular mechanisms underlying physiological and pathological atrial enlargement could provide new therapeutic and diagnostic strategies for preventing or reversing atrial enlargement and AF.

Left atrial strain rate during atrial contraction predicts raised pulmonary capillary wedge pressure: evidence for left atrio-ventricular interaction

This study aimed to assess the relationship between different LA strain components and PCWP as well as to the relationship with other established methods. We studied 144 symptomatic patients, age 63 ± 14 years, 54 males, using conventional transthoracic echocardiography protocols, including LA and LV myocardial deformation from speckle tracking technique investigations along with simultaneous right heart catheterization (RHC) using established techniques. From RHC, pulmonary artery pressure (PAP), and pulmonary capillary wedge pressure (PCWP) were measured and pulmonary vascular resistance (PVR) calculated. LA strain rate during atrial contraction (LASRa) was the strongest correlate with PCWP (r² =  - 0.40, p < 0.001), over and above both LASR during LV systole (LASRs) and LA longitudinal strain during ventricular systole (LASs) (r² = 0.21 and 0.19, respectively, p < 0.001 for both). The correlation between LASRa and PCWP was stronger in patients with post-capillary PH compared to pre-capillary PH (r² = 0.21 vs. r² = 0.02, respectively). The strongest relationship between LASRa and PCWP was in patients with enlarged LA volume > 34 ml/m² (r² = 0.60, p < 0.001). In all patients LASRa <  = 0.9 1/s was 88% accurate in predicting LA pressure > 15 mmHg which was superior to recently proposed uni- and multi-variable models. LASR during atrial contraction is the strongest predictor of PCWP, particularly in patients with post-capillary PH and with dilated LA cavity. Furthermore, it proved superior to recently proposed uni- and multi-variable based algorithms. Its close relationship with LV strain rate counterpart reflects important left heart chamber interaction in patients with raised LA pressure.

Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms

Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.

The role of CT in detecting AF substrate

Despite technological advancements and evolving ablation strategies, atrial fibrillation catheter ablation outcome remains suboptimal for a cohort of patients. Imaging-based biomarkers have the potential to play a pivotal role in the overall assessment and prognostic stratification of AF patients, allowing for tailored treatments and individualized care. Alongside consolidated evaluation parameters, novel imaging biomarkers that can detect and stage the remodelling process and correlate it to electrophysiological phenomena are emerging. This review aims to provide a better understanding of the different types of atrial substrate, and how Computed Tomography can be used as a pre-ablation risk stratification tool by assessing the various novel imaging biomarkers, providing a valuable insight into the mechanisms that sustain AF and potentially allowing for a patient-specific ablation strategy.

Diastolic function assessment by echocardiography: A practical manual for clinical use and future applications

Diastole is an important component of the cardiac cycle, during which time optimum filling of the ventricle determines physiological stroke volume ejected in the succeeding systole. Many factors contribute to optimum ventricular filling including venous return, left atrial filling from the pulmonary circulation, and emptying into the left ventricle. Left ventricular filling is also impacted by the cavity emptying function and also its synchronous function which may suppress early diastolic filling in severe cases of dyssynchrony. Sub-optimum LA emptying increases cavity pressure, causes enlarged left atrium, unstable myocardial function, and hence atrial arrhythmia, even atrial fibrillation. Patients with clear signs of raised left atrial pressure are usually symptomatic with exertional breathlessness. Doppler echocardiography is an ideal noninvasive investigation for diagnosing raised left atrial pressure as well as following treatment for heart failure. Spectral Doppler based increased E/A, shortened E-wave deceleration time, increased E/e', and prolonged atrial flow reversal in the pulmonary veins are all signs of raised left atrial pressure. Left atrial reduced myocardial strain is another correlate of raised cavity pressure (>15 mm Hg). In patients with inconclusive signs of raised left atrial pressure at rest, exercise/stress echocardiography or simply passive leg lifting should identify those with stiff left ventricular which suffers raised filling pressures with increased venous return.

Speckle Tracking-Derived Left Atrial Stiffness Predicts Clinical Outcome in Heart Failure Patients with Reduced to Mid-Range Ejection Fraction

BACKGROUND AND AIM

Left atrial stiffness (LASt) is an important marker of cardiac function, especially in patients with heart failure (HF); it explains symptoms on the basis of pressure transfer to the pulmonary circulation. The aim of this study was to evaluate the relationship between LASt and cardiac events (CE) in HF patients with reduced to mid-range ejection fraction.

METHODS

The study included 215 consecutive ambulatory HF patients with ejection fraction (EF) < 50% (162 HF reduced EF and 53 HF mid-range EF) of mean age 66 ± 11 years and 24.4% females. Peak LA strain (PALS) was measured by speckle tracking echocardiography and E/e' recorded from the apical four-chamber view. Non-invasive LASt was calculated using the equation: LASt = E/e' ratio/PALS. Documented cardiac events (CE) were HF hospitalization and cardiac death.

RESULTS

During a median follow up of 41 ± 34 months, 65 patients (30%) had CE. In multivariate analysis model, only raised LV filling pressure (E/e') (OR = 0.292, (95% CI 0.099 to 0.859), p = 0.02), peak pulmonary artery pressure (PAP) (OR = 1.050 (1.009 to 1.094), p = 0.01), PALS (OR = 0.932 (0.873 to 0.994), p = 0.02) and LASt (OR = 3.781 (1.144 to 5.122), p = 0.001) independently predicted CE. LASt ≥ 0.76% was the most powerful predictor of CE, with 80% sensitivity and 73% specificity (AUC 0.82, CI = 0.73 to 0.87, p < 0.001) followed by PALS ≤ 16%, with 74% sensitivity and 72% specificity (AUC 0.77, CI = 0.71 to 0.84, p < 0.001). These results were consistent irrespective of EF (p < 0.05).

CONCLUSION

In this cohort of ambulatory HFrEF and HFmrEF patients, LASt proved the most powerful predictor of clinical outcome.

Association of Obesity Measures with Atrial Fibrillation Recurrence After Cryoablation in Patients with Paroxysmal Atrial Fibrillation

BACKGROUND Obesity increases the risk of atrial fibrillation (AF) recurrence after ablation. This study explored the relationship between various obesity indexes and risk of recurrence after cryoablation of paroxysmal AF (PAF). MATERIAL AND METHODS Our prospective study included 100 patients with PAF who underwent first cryoablation. Physical examination and fasting blood lipids levels were measured at baseline. Seven obesity indexes were determined: body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), waist-hip ratio (WHR), cardiometabolic index (CMI), lipid accumulation product (LAP), and body adiposity index (BAI). AF recurrence was confirmed by electrocardiograms and Holter monitor at follow-up visits after the initial 3-month blanking period. Receiver operating characteristic (ROC) curves were drawn to assess the abilities of obesity indicators in predicting AF recurrence. Multivariable Cox regression analysis was used to examine independent predictors of AF recurrence. RESULTS During a mean follow-up of 13.4 months, 31 patients (31.0%) had recurrent AF. Patients with recurrence had higher BMI, WC, WHtR, LAP, and BAI compared with those without recurrence. ROC analysis indicated the potential predictive value of BAI with an AUC of 0.657 (95% confidence interval [CI]: 0.534-0.779), followed by WC, WHtR, LAP, and BMI (all P<0.05). Diagnosis-to-ablation time (HR 1.034, 95% CI: 1.002-1.068), left atrial diameter (HR 1.147, 95% CI: 1.026-1.281), and WC (HR 1.026, 95% CI: 1.000-1.053) were independent predictive factors for AF recurrence after multivariable adjustment. CONCLUSIONS In this study population, WC appears to be a potential indicator for the prediction of recurrence in patients with PAF after cryoablation.