Left atrium remodeling predicts late recurrence of paroxysmal atrial fibrillation after second generation cryoballoon ablation

Evaluating the consistency in different methods for measuring left atrium diameters

BACKGROUND

The morphological information of the pulmonary vein (PV) and left atrium (LA) is of immense clinical importance for effective atrial fibrillation ablation. The aim of this study is to examine the consistency in different LA diameter measurement techniques.

METHODS

Retrospective imaging data from 87 patients diagnosed with PV computed tomography angiography were included. The patients consisted of 50 males and 37 females, with an average age of (60.74 ± 8.70) years. Two physicians independently measured the anteroposterior diameter, long diameter, and transverse diameter of the LA using six different methods. Additionally, we recorded the post-processing time of the images. Physician 1 conducted measurements twice with a one-month interval between the measurements to assess intra-rater reliability. Using the intraclass correlation coefficient (ICC), the consistency of each LA diameter measurement by the two physicians was evaluated. We compared the differences in the LA diameter and the time consumed for measurements using different methods. This was done by employing the rank sum test of a randomized block design (Friedman M test) and the q test for pairwise comparisons among multiple relevant samples.

RESULTS

(1) The consistency of the measured LA diameter by the two physicians was strong or very strong. (2) There were statistical differences in the anteroposterior diameter, long diameter, and transverse diameter of LA assessed using different methods (χ2 = 222.28, 32.74, 293.83, P < 0.001). (3) Different methods for measuring the diameters of LA required different amounts of time (χ2 = 333.10, P < 0.001).

CONCLUSION

The results of left atrium (LA) diameter measurements conducted by different physicians were found to be reliable. However, the LA diameters obtained through various techniques exhibited variations. It was observed that measuring LA long diameters using only the VR (volume rendering) picture was the most clinically applicable method.

Clinical Impact of Cryoballoon Ablation for Paroxysmal Atrial Fibrillation in Patients With Enlarged Left Atrium

The impact of cryoballoon ablation (CBA) for atrial fibrillation (AF) in patients with enlarged left atrium (E-LA) has not been sufficiently clarified. A total of 306 patients underwent an initial CBA for paroxysmal AF between February 2017 and March 2022 in our hospital. These patients were categorized into 2 groups according to the preprocedural left atrium (LA) diameter (LAD): E-LA group with LAD ≥40 mm and normal LA (N-LA) group with LAD <40 mm. We compared late recurrence (LR, defined as a recurrence of atrial tachyarrhythmia more than 3 months after the ablation) between the 2 groups. In addition, we made a further classification of the E-LA group into a severely E-LA (SE-LA) group with LAD ≥50 mm and mildly enlarged LA (ME-LA) group with LAD <50 mm and compared LR in the SE-LA, ME-LA, and N-LA groups. In the patients who experienced a second ablation procedure owing to LR, subsequent recurrences were also evaluated. After initial CBA, there was no significant difference in recurrence-free survival between E-LA and N-LA groups (p = 0.447). In contrast, the SE-LA group showed the lowest incidence of recurrence-free survival in the SE-LA, ME-LA, and N-LA groups (p = 0.012). However, when we analyzed recurrences after the ablation including second ablation procedure, there were no significant differences in recurrence-free survival among these 3 groups (p = 0.103). In conclusion, patients with paroxysmal AF with enlarged LA showed favorable outcomes compared with those with N-LA after CBA.

Comparison of left atrial and left atrial appendage mechanics in the recurrence of atrial fibrillation after radiofrequency catheter ablation

OBJECTIVES

Although radiofrequency catheter ablation (RFCA) has become an important treatment strategy for paroxysmal or persistent atrial fibrillation (AF), AF recurrence after RFCA remains an important issue that plagues clinicians and patients. This study aimed to investigate the association of left atrial (LA) and left atrial appendage (LAA) mechanics with AF recurrence after RFCA and to compare their prognostic values in patients with AF undergoing RFCA.

METHODS

A total of 160 patients with non-valvular AF who underwent RFCA for the first time were included in this study. All patients underwent transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) before the procedure. All patients were followed up for one year after RFCA, and AF recurrence was recorded. Speckle-tracking echocardiography was used to measure LA and LAA global longitudinal strain (GLS). LA and LAA mechanical dispersion (MD) were defined as the standard deviation of time to peak strain at each segment standardized by the R-R interval. Logistic regression analysis was used to analyze independent contributors for AF recurrence after RFCA. The prediction efficiency of factors associated with the presence of AF recurrence was evaluated by the receiver operating characteristic (ROC) curve with area under curve (AUC).

RESULTS

During 1-year follow-up, 45 (28%) patients had recurrence, and 115 (72%) patients had no recurrence. The age, CHA2 DS2 -VASc score, NT-proBNP, LA volume index (LAVI), LA MD, and LAA MD of patients in recurrence group were significantly higher than those in no recurrent group (p < .05). The LAA emptying fraction (LAAEF), LA GLS, and LAA GLS in recurrence group were significantly lower than those in no recurrent group (p < .05). Logistic regression analysis showed that LA and LAA GLS were independent contributors for AF recurrence (p < .05), providing incremental values. The AUCs of LA and LAA GLS in predicting AF recurrence were higher than that of other factors, and the LA GLS+LAA GLS joint model had higher prediction efficiency.

CONCLUSION

This study demonstrated the LA and LAA GLS were independent contributors for AF recurrence after RFCA and provided incremental values. LA and LAA GLS can be used as the predictor of AF recurrence after RFCA, and they may be beneficial for the risk stratification of AF recurrence.

Left atrial strain is associated with arrhythmia recurrence after atrial fibrillation ablation: Cardiac magnetic resonance rapid strain vs. feature tracking strain

PURPOSE

The present study assesses different left atrial (LA) strain approaches in relation to atrial fibrillation (AF) recurrence after ablation and compares LA feature tracking (FT) strain to novel rapid LA strain approaches in AF patients.

METHODS

This retrospective single-center study comprised of 110 prospectively recruited AF patients who underwent cardiac magnetic resonance (CMR) imaging in sinus rhythm prior to their first pulmonary vein isolation ablation. LA rapid strain (long axis strain and atrioventricular (AV)-junction strain), LA FT strain, and LA volumes were derived from 2-chamber and 4-chamber cine images. AF recurrence was followed up for 12 months using either 12‑lead ECGs or rhythm Holter monitoring.

RESULTS

Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (122-286) days. LA long axis strain, AV-junction strain, and FT strain were all more impaired in patients with AF recurrence compared to patients without AF recurrence (long axis strain: P < 0.01; AV-junction strain: P < 0.001; FT strain: P < 0.01, respectively). Area under the curve (AUC) values for LA remodeling parameters in association with AF recurrence were 0.68 for long axis strain, 0.68 for AV-junction strain, 0.66 for FT strain, 0.66 for LA volume index. Phasic FT LA strain demonstrated that contractile strain had the highest AUC (0.70).

CONCLUSION

Both LA rapid strain and LA FT strain are associated with arrhythmia recurrence after ablation in AF patients. LA rapid strain can be a convenient and reproducible alternative for LA FT strain to assess LA function in clinical practice.

[Potential risk factors of atrial fibrillation recurrence after cryoballoon ablation]

Aim      To identify risk factors for recurrence of atrial fibrillation (AF) following cryoballoon ablation (CBA).Material and methods  This prospective study included patients with paroxysmal AF who had undergone CBA (141 patients, median age 60 years, 3% men). The evaluation prior to CBA included clinical instrumental parameters (electrocardiography (ECG), 24-h ECG monitoring, echocardiography, contrast-enhanced cardiac multispiral computed tomography). Also, possible intraoperative indexes that could affect the CBA effectivity, were evaluated. The postoperative follow-up duration was 12 months. Effectivity was assessed during in-person visits at 3, 6, and 12 months, when questioning of patients and 24-h ECG monitoring were performed. CBA was considered ineffective if the patient had recurrences of any atrial tachyarrhythmia longer than 30 sec after the end of the 3-month "blind" period.Results During the 12-month follow-up, recurrences of atrial tachyarrhythmia were observed in 46 (32.6 %) patients. Patients with ineffective CBA more frequently had AF during the first 3 months (71.7 % vs. 11.6 %; р&lt;0.001). Such patients had a history of multiple ineffective treatments with antiarrhythmic drugs (AAD), common pulmonary venous (PV) collector (41.3 % vs. 20.0 %; р=0.008), and stroke/recurrent ischemic attacks (15.2 % vs. 5.2 %; р=0.047). Multifactorial regression analysis showed that the factors of AF recurrence included common PV collector (relative risk (RR) 2.35; 95 % confidence interval (CI) 1.29-4.25; р=0.005), multiple ineffective AADs (RR 1.42; 95 % CI 1.08-1.86; р=0.011), and early AF recurrence (RR 7.57; 95 % CI 3.84-14.90; р&lt;0.001).Conclusion      Common PV collector and multiple ineffective AADs are risk factors of ineffective CBA. Early recurrences during the first 3 postoperative months are a significant risk factor of long-term AF recurrences.

Early Echocardiographic Predictors for Atrial Fibrillation Propensity: The Left Atrium Oracle

Atrial fibrillation (AF) results from structural and electrical remodeling of the atria, primarily of the left atrium (LA); therefore, LA changes, both anatomical and functional are recognized as proarrhythmic markers with a powerful prognostic value. Being widely available and noninvasive, echocardiography is used to monitor LA form and function in clinical practice. Early functional (electrical) remodeling of the LA precedes anatomical alterations. Impaired LA functions and reduced atrial compliance due to atrial fibrosis may be evaluated using novel echocardiographic techniques, such as tissue Doppler analysis and speckle tracking. Functional evaluation of the LA conveys prognostic information about the risk of AF, as the severity of the impairment is an independent predictor of new-onset AF and AF recurrence. However, specific parameters are still investigated for incorporation into algorithms to predict future AF occurrence. The aim of the review is to summarize echocardiographic parameters, their predicting value and applicability in practice.

Additional value of left atrium remodeling assessed by three-dimensional echocardiography for the prediction of atrial fibrillation recurrence after cryoballoon ablation

Cryoballoon ablation (CBA) is a safe and efficient therapeutic option for atrial fibrillation (AF). However, AF recurrence occurs in 25% of the patients, leading to repeated ablations and complications. Previous reports have shown that left atrium (LA) assessed by M-Mode and two-dimensional echocardiography (2DE) predicts AF recurrence. Nevertheless, these methods imply geometrical assumptions of the LA remodeling, which is a three-dimensional process. We hypothesized that LA remodeling by three-dimensional echocardiography (3DE) has an additional value for AF recurrence prediction post-CBA. 172 consecutive patients (62.2 ± 12.2 years, 61% male) were prospectively recruited. Echocardiography was performed before CBA. Blanking period was defined as the first three months post-ablation. The primary endpoint was AF recurrence after the blanking period. 50 (29%) patients had AF recurrence. 3DE LA maximum volume index (LAVI) had the highest incremental predictive value for AF recurrence (HR 5.50, 95% CI 1.34 -22.45, p < 0.001). In patients with non-dilated LA diameter index and LAVI by 2DE, LAVI by 3DE was able to discriminate AF recurrence with a sensitivity of 90% and a specificity of 66%, for an optimal cut-off value of 30.4 ml/m2. LA remodeling by 3DE predicted AF recurrence, even in patients with non-dilated LA by M-Mode and 2DE, suggesting that 3DE might reflect better and earlier the asymmetric and variable nature of LA remodeling and it should be considered for systematic use to evaluate AF recurrence risk post-CBA.

Efficacy of Cryoballoon Ablation for Atrial Fibrillation and Recurrence Predictors in an Asian Cohort

Background: Cryoballoon ablation (CBA) for atrial fibrillation (AF) is a rhythm control procedure used in clinical trials, mostly in Western countries. Its efficacy and the predictors of AF recurrence after CBA remain unclear for Asian populations. We aimed to investigate the efficacy of CBA and the predictors of AF recurrence after CBA in Asian AF patients. Methods: We included consecutive AF patients undergoing CBA for rhythm control between 2014 and 2020. The baseline characteristics, including AF types, symptom severity, and left atrial diameter (LAD), were analyzed. Holter’s monitoring and 12-lead ECG were performed to document AF recurrence. A multivariate Cox hazards regression model was used to evaluate the risk of AF recurrence. Results: A total of 120 AF patients (aged 61.9 ± 9.3 years) were included. The percentage of patients free from AF in the year following CBA was 74.2%. Among the three independent predictors of AF recurrence within one year were the presence of persistent AF (p = 0.025), an LAD ≥ 4.75 cm (p = 0.016), and pre-procedural cardioversion (p = 0.025). All patients survived and none had a stroke after CBA. Conclusion: CBA for AF is an effective and safe procedure in Asian populations. The presence of persistent AF, an LAD ≥ 4.75 cm, and severe symptoms are predictors of AF recurrence in the year following CBA.

Incremental value of left atrial strain to predict atrial fibrillation recurrence after cryoballoon ablation

Objective

Atrial fibrillation (AF) recurrence occurs in approximately 25% of the patients undergoing cryoballoon ablation (CBA), leading to repeated ablations and complications. Left atrial (LA) dilation has been proposed as a predictor of AF recurrence. However, LA strain is a surrogate marker of LA mechanical dysfunction, which might appear before the enlargement of the LA. The purpose of this study was to evaluate the additional predictive value of LA function assessed using strain echocardiography for AF recurrence after CBA.

Methods

172 consecutive patients (62.2 ± 12.2 years, 61% male) were prospectively analyzed. Echocardiography was performed before CBA. Blanking period was defined as the first three months post-ablation. The primary endpoint was AF recurrence after the blanking period.

Results

50 (29%) patients had AF recurrence. In the overall study population, peak atrial longitudinal strain (PALS) ≤ 17% had the highest incremental predictive value for AF recurrence (HR = 9.45, 95%CI: 3.17–28.13, p < 0.001). In patients with non-dilated LA, PALS≤17% remained an independent predictor of AF recurrence (HR = 5.39, 95%CI: 1.66–17.52, p = 0.005).

Conclusions

This study showed that LA function assessed by PALS provided an additional predictive value for AF recurrence after CBA, over LA enlargement. In patients with non—dilated LA, PALS also predicted AF recurrence. These findings emphasize the added value of LA strain, suggesting that it should be implemented in the systematic evaluation of AF patients before CBA.

Minimum Left Atrial Volume Evaluated by 3D Echocardiography Predicts Atrial Fibrillation Recurrences After a First Radiofrequency Catheter Ablation for Paroxysmal Episodes

Background: Concomitant atrial fibrillation (AF) in non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients complicates the decision-making process regarding short- and long-term antithrombotic strategies. Patient profiles and usage rates of different antithrombotic combinations in this patient subgroup in Romania are poorly described. Study aim: To evaluate the relationship between LA dimensions and AF recurrences (AFR) using echocardiography. Methods: We enrolled 40 patients (56 ± 10 years; 73% males) who underwent a first RFCA for paroxysmal AF. Bi- (2DE) and three-dimensional (3DE) echocardiography was performed prior to RFCA and at 12-months follow-up. Rhythm control was monitored for up to two years after the intervention by periodic ECG Holter monitoring. Results: Atrial fibrillation recurrences were recorded in 21 patients (52%) in the first year after RCFA. The only predictor of outcome from pre-ablation LA parameters was 3DE minimum LAVi (p = 0.042), that explained 21.4% of AF recurrences in the first year, with a cut-off value of 21.29 mL/m². The mean 3DE min LAVi was 24.29 ± 8.01 mL/ m² and patients without AFR in the first year had a lower LAVi than those with AFR (20.92 ± 6.19 mL/m² vs. 27.25 ± 8.43 mL/m², p=0.028). One year after RFCA, a decrease in medio-lateral, superior-inferior diameters and volumes were recorded in AF free patients. Eleven patients (27%) had AF recurrences after the first year and LAV 12-months after RFCA were found to be predictors of long-term outcome, with minimum LAVi as the strongest predictor of recurrences (p=0.014), explaining 36% of episodes, with a cut-off over 22.49 mL/m². Conclusion:Radiofrequency ablation controls LA remodeling in patients with clinical success in terms of AF freedom. Left atrium 3DE volumetry is accurate in predicting RFCA outcome.

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.

The impact of left atrium size on selection of the pulmonary vein isolation method for atrial fibrillation: Cryoballoon or radiofrequency catheter ablation

BACKGROUND

Pulmonary vein isolation (PVI) is the cornerstone of ablation strategies for atrial fibrillation (AF), and noninferiority of cryoballoon (CB) over radiofrequency (RF) ablation has been previously reported. One of the risk factors of recurrence is left atrium (LA) enlargement. This study aimed to analyze the impact of LA enlargement on the selection of CB or RF ablation for AF patients.

METHODS

A total of 2,224 AF patients (64.4 ± 10.7 years, 65.5% male) who underwent PVI were analyzed retrospectively. Left atrial diameter (LAD) and volume (LAV) were measured using echocardiography before the procedures. LA enlargement was defined as LAD ≥40 mm and LAV index (LAVI) ≥35 mL/m². Patients undergoing CB and RF ablation were propensity score matched, and 376 matched pairs were evaluated.

RESULTS

Cox proportional hazard analysis revealed that LAD (95% CI, 1.01-1.05), LAV (95% CI, 1.01-1.02), and LAVI (95% CI, 1.01-1.03) were independent predictors of recurrence. CB showed equivalent clinical outcomes to those of RF with shorter procedure time required for patients without LA enlargement. CB was inferior to RF in patients with LA enlargement (LAD, 74.5% vs 84.6%, P = .028; LAVI, 74.7% vs 83.4%, P = .015), and large LAVI was associated with a higher prevalence of non-PV foci (35% vs 29%, P = .008).

CONCLUSIONS

CB ablation may be recommended for patients without enlarged LA based on the short procedure time and efficacy, whereas RF would be more appropriate in large LAs. LAVI may be a valuable reference to predict PVI outcomes and in selecting the ablation method.