Impact of right atrial structural remodeling on recurrence after ablation for atrial fibrillation

Right atrial reverse remodeling after pulmonary vein isolation: Analyzing changes in volume and function using cardiac magnetic resonance imaging

BACKGROUND

Successful pulmonary vein isolation (PVI) promotes left atrial (LA) reverse remodeling, but its effect on right atrial (RA) remodeling remains unclear.

OBJECTIVE

The purpose of this study was to assess the impact of radiofrequency (RF) PVI on RA volumes and function in patients with atrial fibrillation by using cardiac magnetic resonance imaging.

METHODS

Forty-three patients with atrial fibrillation (32 (74.4%) males; mean age 61±7 years) undergoing first RF PVI, without atrial flutter ablation, underwent 3 cardiac magnetic resonance scans: pre-PVI, early (<72 hours) post-PVI, and 3 months post-PVI. Indexed atrial volumes (RA maximal/minimal volume index and LA maximal/minimal volume index) and function were derived from 2- and 4-chamber cine images, with longitudinal atrial strain analyzed using feature tracking.

RESULTS

Early post-PVI, RA minimal volume index significantly decreased (from 28.7±10.3 to 26.0±9.9 mL/m2; P=.03) while RA emptying fraction significantly increased (from 37.3%±11.5% to 41.7%±10.1%; P=.03). At 3 months, both RA minimal volume index and RA maximal volume index showed further significant reductions compared with baseline (from 28.7±10.3 to 24.8±8.8 mL/m2; P=.002 and from 45.2±11.8 to 40.3±11.9 mL/m2; P<.001, respectively). During this period, RA functional improvement persisted, as evidenced by RA reservoir and contractile strain (from 16.2%±4.1% to 18.9%±3.6%; P=.003 and from 6.6%±2.6% to 8.3%±2.8%; P=.005, respectively). LA volumes remained unchanged early post-PVI, but at 3 months, LA maximal volume index significantly decreased compared with baseline (from 46.1±13.0 to 39.1±11.3 mL/m2; P<.001). LA function, demonstrated by reservoir and contractile strain, was significantly diminished early post-PVI, which persisted at 3 months compared with baseline (from 18.6%±4.0% to 17.0%±3.4%; P=.04 and from 8.5%±3.0% to 6.9%±2.4%; P<.01, respectively).

CONCLUSION

This study demonstrates that RF PVI results in reverse biatrial remodeling, with significant reductions observed in RA and LA volumes. RA function showed a significant improvement post-PVI, while LA function demonstrated persistent impairment at 3 months, possibly because of LA ablation scarring.

Right atrial volume index and right atrial volume predict atrial fibrillation recurrence: A meta-analysis

BACKGROUND

Atrial volume index and atrial volume have recently been identified as predictors of atrial fibrillation (AF) recurrence following electrical cardioversion or radiofrequency ablation. However, most studies have reported the relationship between LAVI/LAV and AF recurrence, whereas there is little information on the relationship between RAVI/RAV and AF recurrence. Therefore, we performed a meta-analysis to assess the relationship between the risk of AF recurrence and RAVI/RAV in patients with AF who underwent electrical cardioversion or radiofrequency ablation.

METHODS

CNKI, Wanfang Database, Pubmed, Embase, Cochrane Library, and Web of Science were searched up to October 01, 2024. A meta-analysis of relative risk data from prospective and retrospective cohort studies that reported on the relationship between the risk of AF recurrence and RAVI/RAV in patients with AF after electrical cardioversion or radiofrequency ablation was performed.

RESULTS

The results showed that patients with AF recurrence had a higher mean right atrial volume index (RAVI) compared to patients with no recurrence. After electrical cardioversion or radiofrequency ablation, RAVI can independently predict the recurrence of AF (OR = 1.06, 95%CI (1.02, 1.11)). The average right atrial volume (RAV) of patients with AF recurrence was higher than that of patients without AF recurrence. After electrical cardioversion or radiofrequency ablation, RAV can independently predict the recurrence of AF (OR = 1.02, 95%CI (1.00, 1.05)).

CONCLUSION

Patients with AF recurrence after electrical cardioversion or radio frequency ablation had higher mean RAVI and RAV compared to patients with no recurrence. After electrical cardioversion or radiofrequency ablation in patients with AF, higher levels of RAVI and RAV increase the chance of recurrence of AF.

Deep learning-based workflow for automatic extraction of atria and epicardial adipose tissue on cardiac computed tomography in atrial fibrillation

BACKGROUND

Preoperative estimation of the volume of the left atrium (LA) and epicardial adipose tissue (EAT) on computed tomography (CT) images is associated with an increased risk of atrial fibrillation (AF) recurrence. We aimed to design a deep learning-based workflow to provide reliable automatic segmentation of the atria, pericardium, and EAT for future applications in the management of AF.

METHODS

This study enrolled 157 patients with AF who underwent first-time catheter ablation between January 2015 and December 2017 at Taipei Veterans General Hospital. Three-dimensional (3D) U-Net models of the LA, right atrium (RA), and pericardium were used to develop a pipeline for total, LA-EAT, and RA-EAT automatic segmentation. We defined fat within the pericardium as tissue with attenuation between -190 and -30 HU and quantified the total EAT. Regions between the dilated endocardial boundaries and endocardial walls of the LA or RA within the pericardium were used to detect voxels attributed to fat, thus estimating LA-EAT and RA-EAT.

RESULTS

The LA, RA, and pericardium segmentation models achieved Dice coefficients of 0.960 ± 0.010, 0.945 ± 0.013, and 0.967 ± 0.006, respectively. The 3D segmentation models correlated well with the ground truth for the LA, RA, and pericardium ( r = 0.99 and p < 0.001 for all). The Dice coefficients of our proposed method for EAT, LA-EAT, and RA-EAT were 0.870 ± 0.027, 0.846 ± 0.057, and 0.841 ± 0.071, respectively.

CONCLUSION

Our proposed workflow for automatic LA, RA, and EAT segmentation using 3D U-Nets on CT images is reliable in patients with AF.

Enlarged right atrium predicts pacemaker implantation after atrial fibrillation ablation in patients with tachycardia-bradycardia syndrome

Introduction

Although catheter ablation (CA) of tachycardia-bradycardia syndrome (TBS) in patients with atrial fibrillation (AF) is considered to be an effective treatment strategy, pacemaker implantations (PMIs) are often required even after a successful CA. This study aimed to elucidate the clinical predictors of a PMI after CA.

Methods

From 2011 to 2020, 103 consecutive patients diagnosed with TBS were retrospectively enrolled in the study. Among the 103 patients, 54 underwent a PMI and 49 CA of AF. During 47.4 ± 35.4 months after 1.4 ± 0.6 CA sessions, 37 (75.5%) of 49 patients were free from atrial arrhythmia recurrences. PMIs were performed in 11 patients (PMI group) and the remaining 38 did not receive a PMI (non-PMI group).

Results

When comparing the PMI and non-PMI groups, there were no differences in the basic mean heart rate (P = 0.36), maximum pauses detected by 24-hour Holter-monitoring (P = 0.61), and other clinical parameters between the two groups while the right atrial area index was larger (42.1 ± 24.0 vs. 21.8 ± 8.4 cm2/m2 P = 0.002) in the PMI group than non-PMI group. The ROC curve analysis showed that the optimal cutoff point of the ratio of the right atrial area index to the left atrial area index for predicting a PMI following CA was 0.812 (Sensitivity 72.7%, specificity 71.1%, positive predictive value 42.1%, negative predictive value 90.0%, diagnostic accuracy 71.4%, AUC = 0.81).

Conclusion

Right atrial enlargement prior to CA was considered to be one of the risk factors for a PMI after CA of AF.

Characterization of unipolar electrogram morphology: a novel tool for quantifying conduction inhomogeneity

AIMS

Areas of conduction inhomogeneity (CI) during sinus rhythm may facilitate the initiation and perpetuation of atrial fibrillation (AF). Currently, no tool is available to quantify the severity of CI. Our aim is to develop and validate a novel tool using unipolar electrograms (EGMs) only to quantify the severity of CI in the atria.

METHODS AND RESULTS

Epicardial mapping of the right atrium (RA) and left atrium, including Bachmann's bundle, was performed in 235 patients undergoing coronary artery bypass grafting surgery. Conduction inhomogeneity was defined as the amount of conduction block. Electrograms were classified as single, short, long double (LDP), and fractionated potentials (FPs), and the fractionation duration of non-single potentials was measured. The proportion of low-voltage areas (LVAs, <1 mV) was calculated. Increased CI was associated with decreased potential voltages and increased LVAs, LDPs, and FPs. The Electrical Fingerprint Score consisting of RA EGM features, including LVAs and LDPs, was most accurate in predicting CI severity. The RA Electrical Fingerprint Score demonstrated the highest correlation with the amount of CI in both atria (r = 0.70, P < 0.001).

CONCLUSION

The Electrical Fingerprint Score is a novel tool to quantify the severity of CI using only unipolar EGM characteristics recorded. This tool can be used to stage the degree of conduction abnormalities without constructing spatial activation patterns, potentially enabling early identification of patients at high risk of post-operative AF or selection of the appropriate ablation approach in addition to pulmonary vein isolation at the electrophysiology laboratory.

Asymmetric remodeling between the left and right atria in patients with advanced interatrial block and atrial fibrillation

BACKGROUND

Advanced interatrial block (A-IAB) on electrocardiography (ECG) represents the conduction delay between the left and right atria. We investigated the association of A-IAB with left and right atrial (LA/RA) remodeling in patients with atrial fibrillation (AF).

METHODS

We enrolled 74 patients who underwent ECG, cardiac computed tomography (CCT), and echocardiography during sinus rhythm before catheter ablation of AF. A-IAB was defined as P-wave duration ≥120 ms with a biphasic morphology in leads III and aVF or notched morphology in lead II. We compared the maximum and minimum LA/RA volume indices (max and min LAV/RAVI), LA/RA expansion index (LAEI/RAEI), and total, passive, and active LA/RA emptying fraction (LAEF/RAEF) between patients with and without A-IAB.

RESULTS

Of the 74 patients (mean age, 64.3 ± 9.6 years), 35 (47%) showed A-IAB. Patients with A-IAB had a significantly higher likelihood of hypertension and left ventricular diastolic dysfunction than those without. Patients with A-IAB had significantly larger max (69.2 [60.7-79.7]mL/m2 vs. 60.9 [50.4-68.3]mL/m2, P < 0.01) and min (44.0 [37.2-52.1]mL/m2 vs. 34.1 [29.2-43.5]mL/m2, P < 0.01) LAVI than those without. The max and min RAVI were not significantly different between groups. LAEI (55.1 [48.2-78.5]% vs. 72.1 [57.8-84.8]%, P < 0.05), total LAEF (35.5 [32.5-44.0]% vs. 41.9 [36.6-45.9]%, P < 0.05), and passive LAEF (12.2 [10.0-14.4]% vs. 15.5 [11.2-19.6]%, P < 0.05) were significantly lower in patients with A-IAB than without.

CONCLUSIONS

A-IAB was associated with LA, but not RA enlargement, in patients with AF. A-IAB may indicate LA functional remodeling in the reservoir and conduit phases.

Incremental Value of Right Atrial Strain Analysis to Predict Atrial Fibrillation Recurrence After Electrical Cardioversion

BACKGROUND

Although the assessment of left atrial (LA) mechanics has been reported to refine atrial fibrillation (AF) risk prediction, it doesn't completely predict AF recurrence. The potential added role of right atrial (RA) function in this setting is unknown. Accordingly, this study sought to evaluate the added value of RA longitudinal reservoir strain (RASr) for the prediction of AF recurrence after electrical cardioversion (ECV).

METHODS

We retrospectively studied 132 consecutive patients with persistent AF who underwent elective ECV. Complete two-dimensional and speckle-tracking echocardiography analyses of LA and RA size and function were obtained in all patients before ECV. The end point was AF recurrence.

RESULTS

During a 12-month follow-up, 63 patients (48%) showed AF recurrence. Both LASr and RASr were significantly lower in patients experiencing AF recurrence than in patients with persistent sinus rhythm (LASr, 10% ± 6% vs 13% ± 7%; RASr, 14% ± 10% vs 20% ± 9%, respectively; P < .001 for both). Right atrial longitudinal reservoir strain (area under the curve = 0.77; 95% CI, 0.69-0.84; P < .0001) was more strongly associated with the recurrence of AF after ECV than LASr (area under the curve = 0.69; 95% CI, 0.60-0.77; P < .0001). Kaplan-Meier curves showed that patients with both LASr ≤ 10% and RASr ≤ 15% had a significantly increased risk for AF recurrence (log-rank, P < .001). However, at multivariable Cox regression, RASr (hazard ratio, 3.26; 95% CI, 1.73-6.13; P < .001) was the only parameter independently associated with AF recurrence. Right atrial longitudinal reservoir strain was more strongly associated with the occurrence of AF relapse after ECV than LASr, and LA and RA volumes.

CONCLUSION

Right atrial longitudinal reservoir strain was independently and more strongly associated than LASr with AF recurrence after elective ECV. This study highlights the importance of assessing the functional remodeling of both the RA and LA in patients with persistent AF.

Pre-procedural high serum visfatin and tumor necrosis factor-α might predict recurrent atrial fibrillation after catheter ablation

BACKGROUND

Many patients would require repeated ablation procedures owing to recurrent atrial fibrillation with its associated symptoms. Identifying those who are at risk of recurrent AF could assist us to develop preventive strategies and to properly select those who will benefit more from catheter ablation. Our aim is to study the role of preprocedural serum level of certain biomarkers in the prediction of AF recurrence after catheter ablation.

RESULTS

The present study included 117 patients: 26 patients with persistent and 91 patients with paroxysmal AF. Blood samples for estimation of serum levels of studied cytokines were obtained prior to the procedure. Pulmonary vein isolation was performed in all patients through point-by point radiofrequency ablation guided by 3D electroanatomical mapping system. Patients were followed for 12 months for AF recurrence. Forty-one (35%) patients developed AF recurrence. Those patients were significantly older, had significantly higher BMI, lower ejection fraction, and wider maximal left atrial diameter (LAD). Serum hs-CRP, IL-6, TNF-α, visfatin, and adiponectin levels were significantly higher compared to those who did not develop AF recurrence. Correlation analysis showed positive correlations between the incidence of RAF and patients' age, BMI, and maximum LAD and elevated cytokine levels and maximal LAD showed significant correlations with the type of AF and elevated serum TNF-α, visfatin, and adiponectin. Statistical analyses defined elevated serum levels of TNF-α, visfatin, and adiponectin as positive predictors for RAF, and automatic linear modeling analysis showed that elevated serum visfatin, TNF-α, and adiponectin can predict RAF by accuracy rates of 50%, 34%, and 16%, respectively.

CONCLUSIONS

RAF is most probably an outcome of the interplay between patients' clinical data, obesity, and inflammation. Pre-procedural estimation of serum levels of visfatin and TNF-α might determine patients with probability for RAF.

The Right Atrial Area as a New Factor to Predict Successful Pulmonary Vein Isolation: an Emergent Predictor Variable

Up to now, few factors have been identified to predict successful pulmonary vein isolation, none of which with high predictive values. The objective of our study was to compare different predictive factors of atrial fibrillation recurrence after pulmonary vein isolation,including new parameters of the right atrium (area and index volume). We retrospectively analysed data from 66 patients and included echocardiogram parameters performed within 18 months prior to the ablation procedure. We excluded patients with left ventricular dysfunction (defined as a left ventricular ejection fraction < 50%); previous diagnostic of cardiomyopathy; severe valvular heart disease; severe pulmonary hypertension; or those with poor image quality in the echocardiogram. We considered atrial fibrillation recurrence to be the presence of atrial fibrillation of 30 seconds or longer demonstrated by a standard electrocardiogram or in a 24-hour Holter electrocardiogram within a year after the ablation procedure. We found that the right atrium area (odds ratio = 1.52; 95% confidence interval 0.95–2.43, P = 0.08) and a previous pulmonary vein isolation procedure (odds ratio = 0.21; 95% confidence interval 0.04–1.01, P = 0.05) were nearly statistically significant predictors of successful atrial fibrillation ablation at one year. Although our study was limited because of a low number of patients and because it is a retrospective analysis, we found that a higher right atrial area may be related to the late recurrence of atrial fibrillation. This tendency may be useful in predicting patient outcomes.