Left Atrial Low-voltage Areas Research Articles

Left atrial low-voltage areas, but not volume, predict the recurrence of atrial fibrillation in repeat ablation procedures

Abstract Background Left atrial (LA) low voltage areas (LVA) are a controversial target in atrial fibrillation ablation procedures. However, LVA and LA volume are good predictors of arrhythmia recurrence in ablation-naïve patients. Their predictive value in pre-ablated, myopathic atria is uncertain. Purpose Patient selection for repeat ablations is sometimes difficult. Predicting factors of rhythm outcome might help with the decision. Methods Consecutive patients with recurrent atrial fibrillation (AF) or atrial tachycardia (AT) scheduled for repeat LA ablation were included in the prospective Bernau ablation registry between 2016 and 2020. All patients received a complete LA ultra-high-density map before ablation. Maps were analyzed for LA size, LVA percentage and distribution. The predictive value of demographic, anatomic and mapping variables on AF recurrence was analyzed in univariate logistic regression and integrated in a multivariate Cox regression if the p-value was <0.250. Results 160 patients (50.6% male, 1.3 pre-ablations, 60% persistent AF) with complete LA voltage maps were included. Mean follow-up time was 16 ± 11 months. Mean recorded electrograms (EGMs) per map were 9754 ± 5808, mean LA volume was 176.1 ± 35.9 ml and mean rate of LVAs < 0.5 mV was 30.6% ± 23.1%. Baseline characteristics are depicted in table 1. During follow-up recurrence rate of AF or AT > 30 seconds was 55.6%. Patients with recurrence had a significant higher percentage of LVAs (40.0% vs. 18.8%, p<.001) but no relevant difference in LA volume (172 vs. 178 ml, p=.299). ROC curves revealed a cut-off of 22% LVAs with highest sensitivity (73.0%) and specificity (71.8%). Based on this cut-off event free survival was significantly higher in the Low LVA group (p<0.01), Figure 1. Other relevant clinical, anatomic or laboratory predictors could not be found in multivariate Cox regression analysis. Conclusion The amount of left atrial LVA is a good predictor for arrhythmia recurrence, even in a cohort of repeat ablations with progressively diseased atria. EAM derived left atrial volume has minor impact on recurrence in this group and should not solely guide the decision in favor or against further invasive treatment. Accomplishing a thorough 3D map of the left atrium to account for LVA should be mandatory in all repeat procedures.Baseline CharacteristicsKaplan-Meier for recurrence and voltage

Intermittent hypoxia is significantly associated with low-voltage areas in patients with atrial fibrillation complicated by obstructive sleep apnea

Abstract Background Obstructive sleep apnea (OSA) is one of risk factors for atrial fibrillation (AF); however, how OSA affects the structural and electrical atrial remodeling is not well described. This study aimed to determine the association of OSA with left atrial (LA) size and LA low-voltage area (LVA), a known arrhythmogenic substrate for AF. Methods Eighty-three patients undergoing catheter ablation of AF (forty-nine with OSA [apnea–hypopnea index: AHI ≥ 5/h] and thirty-four control patients without OSA by full polysomnography or portable monitor) were studied. In all cases, LA maps were created using a three-dimensional electro-anatomical mapping system in sinus rhythm or pacing from the right atrium. LVA was defined as a bipolar voltage < 0.5 mV. %LVA is defined as ratio of LVA to LA area. Results LVA and %LVA were larger in OSA group as compared to Control group (6.0 ± 6.6 vs. 2.6 ± 3.2 cm2, P = 0.003 and 7.5 ± 8.5 vs. 3.5 ± 4.6 %, P = 0.008, respectively). On the other hand, there was no difference in LA size between the two groups. In addition, 3% oxygen desaturation index (ODI) was significantly correlated with %LVA (r = 0.282, P = 0.010), but not with LA size (r = 0.053, P = 0.637). Multiple regression analysis demonstrated that 3%ODI ≥ 30 (3.088, 1.078-8.851, P = 0.036) was significantly associated with %LVA after adjustment. Conclusion In patients with AF complicated by OSA, significant enlargement of the LVA was observed, but there was no evidence of enlargement in LA size. Intermittent hypoxia may be one of the mechanisms of this atrial electro-anatomical remodeling.figure 1figure 2

Left ventricular wall thickening predicts left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation

Abstract Background The success rate of circumferential pulmonary vein isolation (CPVI) remains suboptimal in patients with paroxysmal and persistent atrial fibrillation; moreover, the detection of low voltage areas (LVA) in the left atrium does predict an even higher recurrence rate of atrial tachyarrhythmias after the procedure. Left ventricular wall thickening (LVWT) is known to correlate with left atrial volume; however, no data is available whether LVWT is predictive of the presence of left atrial LVA. Purpose The aim of this study was to investigate whether LVWT is predictive of left atrial LVA and to verify that the presence of LVA confer a higher arrhythmia recurrence rate after catheter ablation for atrial fibrillation. Methods A total of 374 patients who undervent CPVI with the use of 3D electroanatomical mapping system as a primary procedure were enrolled in the study. Transthoracic echocardiography was performed in all patients prior the procedure with measurement of the thickness of the septum and the posterior wall. Patients were classified based on LVWT as normal (females:≤9mm, males:≤10mm), borderline (females:10-11mm, males: 11-12mm) and increased (females:≥12mm, males:≥13mm). A detailed left atrial voltage map was obtained in all patients prior to ablation with the identification of LVA (bipolar voltage <0.5mV with an area >5cm2). Arrhythmia recurrence was defined as documented atrial fibrillation or atrial tachycardia lasting for at least 30 seconds. Results Among 374 patients (mean age: 59.0±10.2 years, 131 females) 94, 195 and 85 were considered to be normal, borderline and increased based on LVWT, respectively. LVA were found in 29.9% (112/374) of patients. According to LVWT, LVA were detected in 16.0% (15/94), 31.3% (61/195) and 42.4% (36/85) in patients with normal, borderline and increased wall thickness, respectively, p=0.005. Patients with left atrial LVA had a higher [60.7% (68/112)] arrhythmia recurrence compared to those without low voltage areas [35.1% (92/262)] during a mean follow-up of 2.1±1.9 years, p<0.0001. Conclusions Left ventricular wall thickening predicts the presence of left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation. Low voltage areas confer a higher arrhyhtmia recurrence rate during follow-up.

Left atrial low-voltage area is associated with poor rhythm outcome and poor efficacy of left atrial additional ablation in patients with long-standing persistent atrial fibrillation ablation

Abstract Background Although left atrial additional ablation other than pulmonary vein (PV) isolation is often performed in order to modify arrhythmogenic substrate, rhythm outcome in patients with long-standing persistent atrial fibrillation (LS-PerAF) is still challenging. Left atrial low-voltage areas (LVAs) is correlated with degeneration of atrial myocardium, and atrial fibrillation (AF) recurrence following catheter ablation. However, in patients with LS-PerAF, the association between the prevalence of LVAs and rhythm outcome has not been clarified. We hypothesized that AF recurrence after AF ablation more frequently occurred in patients with LVAs than in those without, and that the prevalence of LVAs was associated with the efficacy of left atrial additional ablation. Purpose The purpose of this study was to investigate the association between the prevalence of LVAs and rhythm outcome or efficacy of left atrial additional ablation in patients with LS-PerAF ablation. Methods In total, 123 (age, 66 ± 9 years; female, 28 [23%]) consecutive patients who underwent initial ablation for LS-PerAF were included. Left atrial additional ablation was defined as an ablation for left atrium other than PV isolation and ablation for non-PV foci. The definition of LVAs was sites with a bipolar voltage of <0.5 mV covering ≥5 cm² of left atrium. Rhythm outcome after the catheter ablation was followed for 24 months. Results LVAs was found in 31 (25%) patients, and left atrial additional ablation was performed for 31 (25%) patients. Freedom from AF recurrence was significantly lower in patients with LVAs than in those without (Figure 1A). In contrast, freedom from AF recurrence was similar between patients with left atrial additional ablation and those without (Figure 1B). In patients without LVAs, freedom from AF recurrence was significantly higher in patients with left atrial additional ablation than in those without (Figure 2A). On the contrary, in patients with LVAs, freedom from AF recurrence during was similar between patients with left atrial additional ablation and those without (Figure 2B). Conclusions In patients undergoing LS-PerAF ablation, AF recurrence more frequently occurred in patients with LVAs than in those without. Only in patients without LVAs, freedom from AF recurrence was significantly higher in patients with left atrial additional ablation than in those without.Figure 1Figure 2

Predictive value of guideline-referred risk scores in estimating left atrial low voltage areas and recurrence of atrial fibrillation in repeat ablation procedures

Abstract Background Despite advances in mapping and ablation techniques, atrial fibrillation (AF) recurrence remains a challenge after pulmonary vein isolation. Low voltage areas (LVA) in the left atrium are associated with higher recurrence rates after left atrial ablation. Risk scores for evaluating post-ablation recurrences are not well established, although a better patient selection for repeat procedures would be of great help in clinical practice. Purpose Risk scores for prediction of AF recurrence have not been tested in a cohort of repeat ablations. Methods This single-center study includes consecutive patients from the prospective Bernau ablation registry undergoing ultra-high-density (UHD) mapping and repeat ablation for AF/AT recurrence between 2016 and 2020. The potential of seven guideline mentioned risk scores (APPLE, DR-FLASH, MB-LATER, ATLAS, CAAP-AF, BASE-AF 2, ALARMEc) to predict (1) AF/AT recurrence beyond a three-months blanking period after repeat left atrial ablation (Re-PVI ± further LA ablation) and (2) the percentage of left atrial LVA in UHD mapping was investigated. LVA were defined as sites with a bipolar peak-to-peak voltage of <0.5 mV with an extent of >1cm². Optimal cutoff for sensitivity and specificity for LVA and AF/AT recurrence as endpoint was chosen using C statistics with receiver-operator characteristics (ROC). Further ROCs were performed to illustrate the predictive ability of the scores. Pearson correlation was used to test associations between variables. Results 160 patients (mean age 67.9 ± 9.1 years, 60.6% persistent AF, mean AF duration 4.6 ± 3.8 years) with complete left atrial UHD mappings (mean EGMs 9754 ± 5808) were included. Overall recurrence rate over a mean follow-up time of 16 ± 11 months was 55.6%. The predictive value of the investigated risk scores on AF/AT recurrence in our cohort was low (Table 1), with the highest power for CAAP-AF (p = 0.015, AUC = 0.615) and DR-FLASH score (p = 0.040, AUC = 0.594), Figure 1. With respect to left atrial LVA we found a better predictive power for the CAAP-AF (p < 0.001, AUC 0.702), APPLE (p < 0.001, AUC 0.687), DR-FLASH (p < 0.001, AUC 0.688), ATLAS (p = 0.005, AUC 0.634) and ALARMEc (p = 0.007, AUC 0.608) score to predict low voltage based on a calculated cut-off of 22% of total left atrial surface (Figure 1). Conclusion The predictive value of guideline-referred risk scores in estimating AF/AT recurrence after repeat ablation is low and does not seem to be of relevant help in patient selection for further interventional treatment. Some scores demonstrate a fairly good prediction for the amount of left atrial LVA and therefore might help in choosing the right mapping and ablation regime beforehand.

J-curved phenomenon between the prevalence of left atrial low-voltage areas and body mass index existed in patients with atrial fibrillation ablation

Abstract Background Left atrial low-voltage areas (LVAs) were known to be associated with atrial fibrosis and atrial fibrillation (AF) recurrence after catheter ablation. However, the association between body mass index (BMI) and prevalence of LVAs has not been fully elucidated. We hypothesized that LVAs were more frequently found in patients with abnormal BMI than in those with normal BMI. Purpose The purpose of this study was to clarify the association between body mass index (BMI) and the prevalence of LVAs in patients with AF ablation. Methods Between December 2014 and March 2022, 1,479 (age, 68±10 years; female, 500 [34%]) consecutive patients who underwent initial AF ablation were enrolled. BMI was divided into four groups, namely <18.5 kg/m², 18.5-25 kg/m², 25-30 kg/m², ≥30 kg/m². LVAs was defined as areas with bipolar voltage of <0.5 mV covered ≥5 cm² of left atrium. Rhythm outcome following the catheter ablation procedure was also followed for 24 months. Results LVAs were found in 349 (24%) patients. J-curved phenomenon existed between BMI and the prevalence of LVAs (Figure 1). In particular, BMI <18.5 kg/m² was an independent predictor of LVAs on multivariate analysis (odds ratio, 1.9; 95% confidence interval: 1.01–3.5; p=0.046). As for rhythm outcome, there was significant difference in freedom from AF recurrence among groups stratified by BMI (Figure 2). Conclusions Between BMI and the prevalence of LVAs, J-curved phenomenon existed in patients with AF ablation. There was significant difference in rhythm outcome following AF ablation among groups stratified by BMI.Figure 1Figure 2

Characterisation of ablation strategies at redo catheter ablation for atrial fibrillation and predictors of arrhythmia recurrence: results from the AFREDO registry

Abstract Background Patients who have undergone prior pulmonary vein isolation (PVI) for atrial fibrillation (AF) often require a repeat ablation for AF recurrence. The optimal ablative strategy for the redo procedure and predictors of AF recurrence thereafter remain largely unknown. Purpose We aimed to characterise the ablation strategies applied at re-PVI and identify possible predictors of AF recurrence. Methods Our single-centre, retrospective study included all consecutive patients who underwent first redo PVI at our centre from 2017 to 2022. Inclusion criteria required at least one available follow-up visit within the first 12 months after the redo procedure. Ablation strategies of the initial and redo procedure were captured. Kaplan-Meier curves were used to illustrate time of AF recurrence, as classified by predictors of outcome determined by multivariable regression analyses. Results We included 215 patients (39.1% female) with a median age of 66.6 years (IQR 58.6-73.2) at the time of redo procedure. The initial PVI was cryoablation in 39.9%, RFA in 57.7% and surgical ablation in 2.4%. After the initial procedure, 55.8% had paroxysmal AF and 44.2% had persistent AF. At the redo procedure, 25.1% of patients were found to have no PV reconnection, whereas 20.5% had a single reconnected PV, and 54.4% had two or more reconnected PVs. A left-sided flutter ablation was performed in 18.8%, a left atrial (LA) roof line in 16.9%, a posterior mitral isthmus line in 5.2%, an anterior mitral isthmus line in 27.9%, and a posterior box lesion in 8.4%. Overall, 34.4% of patients showed areas of low-voltages in the redo procedure. Patients with areas of low voltages were less likely to have any reconnected PVs in the redo-procedure (p<0.001). After the second ablation procedure, 54.0% experienced AF recurrence. Univariable regression analysis revealed moderate (p=0.006) or severe (p= 0.015) LA dilatation, persistent AF (p=0.005), and posterior LA low voltage areas (p=0.011) as significant predictors of AF recurrence after the redo procedure. The number of reconnected PVs at the re-PVI did not predict AF recurrence (p=0.1090). As illustrated in Fig. 1 and 2, patients with paroxysmal AF experienced less AF recurrence compared to those with persistent AF (log-rank p=0.0025). Moreover, moderate or severe LA dilatation at baseline was associated with more frequent AF recurrences (log-rank p=0.0279). Conclusion A significant proportion of patients undergoing re-PVI experienced AF recurrence. We found that persistent AF and moderate or severe LA enlargement emerged as significant predictors of AF recurrence after the redo procedure. Although PV reconnection was observed in more than two thirds of patients at the re-PVI, it did not predict AF recurrence thereafter. However, patients without PV reconnection had significantly more low-voltage areas, which may be indicative of a different AF recurrence mechanism in this subgroup.Figure 1:Type of AFFigure 2:LA dilatation

First-time catheter ablation outcomes for atrial fibrillation are dependent on low-voltage areas rather than paroxysmal vs. persistent classifications: a REAL-AF study

Abstract Background Left atrial low-voltage areas (LA LVA) measured at time of catheter ablation for atrial fibrillation (AF) have been increasingly recognized as an indicator of atrial fibrosis [1]. However, little is known whether first-time catheter ablation outcomes differ between paroxysmal AF (PAF) and persistent AF (PerAF) in patients with higher LA LVA, which may indicate a more advanced substrate independent of clinical subtype. Purpose To evaluate whether outcomes of first-time catheter ablation for AF are dependent on LA LVA rather than PAF vs. PerAF types in a multicenter registry of patients. Methods The Real-world Experience of Catheter Ablation for the Treatment of Symptomatic PAF and PerAF Using Novel Contact Force Technologies registry (REAL-AF) is a prospective, observational multicenter registry of patients undergoing catheter ablation. We evaluated 4181 patients undergoing first-time catheter ablation for both PAF and PerAF to determine AF recurrence within 12 months. Contact maps were created using a 5-spline high-density catheter. LA LVA was calculated using these contact maps based on a bipolar voltage of <0.50 mV. LA LVA was categorized into low (<5%) vs. high (≥5%) based on preliminary data. Risk of recurrence was analyzed using Cox proportional hazard models. Results Patients with LA LVA ≥5% who underwent first-time catheter ablation for AF (both PAF and PerAF) experienced a higher risk of AF recurrence within 12 months (Hazard ratio (HR): 1.95, p<0.001), see Figure 1. Overall, 82.0% of patients were free of AF in the LA LVA <5% group compared to 69.1% in the LA LVA ≥5% group. This association remained significant in a subpopulation of patients presenting in normal sinus rhythm (N = 2463) at time of ablation (HR: 1.90, p<0.001). 12-month ablation outcomes between PAF and PerAF in patients with LA LVA ≥5% (N = 1590) were not statistically significant (71.0% vs 67.3% respectively, HR: 1.15, p=0.30), see Figure 2. Finally, in the LA LVA <5% group (N = 2591), patients with PerAF had a 1.42 times higher risk for AF recurrence within 12 months after catheter ablation (p=0.04). Conclusion This is the largest real-world registry to date demonstrating that LA LVA ≥5% is associated with a higher risk of AF recurrence within 12 months in patients undergoing first-time catheter ablation for AF. Among patients with LA LVA ≥5%, AF recurrence was not associated with AF type. These findings motivate further studies into using LA LVA as a prognostic tool for patients undergoing first-time catheter ablation for AF and using non-invasive methods to assess this in order to stratify patients further.

Associations of the fibrosis‐4 index with left atrial low‐voltage areas and arrhythmia recurrence after catheter ablation: cardio‐hepatic interaction in patients with atrial fibrillation

AbstractBackgroundThe relationship between liver fibrosis and left atrial (LA) remodeling in atrial fibrillation (AF) remains uncertain. We examined the associations between the fibrosis‐4 (FIB4) index, an indicator of liver fibrosis, and both LA low‐voltage areas (LVAs) on electroanatomic mapping and AF recurrence postablation.MethodsWe recruited 343 patients who underwent radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CBA) for AF. First, the association between the FIB4 index and LA LVAs (<0.5 mV) was evaluated in RFCA using electroanatomic mapping (n = 214). Next, the utility of a FIB4 index ≥1.3, recommended cut‐off value of liver fibrosis, was verified to assess the risk for AF recurrence in CBA without additional LVA ablation (n = 129).ResultsPatients with a FIB4 index ≥1.3 had a higher prevalence of LA LVAs (>5 cm2) compared to those without. Additionally, the quantitative size of LVAs showed a positive correlation with the FIB4 index (R = .642, p < .001). In multivariate logistic models, a FIB4 index ≥1.3 was related to the presence of LVAs after adjusting for LA diameter, right atrial end‐systolic area, and nonparoxysmal AF (odds ratio 2.508; p = 0.039). In CBA, AF recurrence rate was 13.1% during 3–12 months postablation. In multivariate Cox models, a FIB4 index ≥1.3 was an important predictor of AF recurrence (hazard ratio 3.796; p = .037), suggesting that LVAs might be associated with AF recurrence after CBA.ConclusionThe FIB4 index was a novel predictor of the existence of LA LVAs on electroanatomic mapping and AF recurrence after CBA.

Left atrial low-voltage areas, but not volume, predict the recurrence of atrial fibrillation in repeat ablation procedures.

Left atrial (LA) low voltage areas (LVA) are a controversial target in atrial fibrillation ablation procedures. However, LVA and LA volume are good predictors of arrhythmia recurrence in ablation-naïve patients. Their predictive value in progressively diseased pre-ablated atria is uncertain. Consecutive patients with recurrent atrial fibrillation (AF) or atrial tachycardia (AT), who were scheduled for repeat LA ablation, were enrolled in the prospective Bernau ablation registry between 2016 and 2020. All patients received a complete LA ultrahigh-density map before ablation. Maps were analyzed for LA size, LVA percentage and distribution. The predictive value of demographic, anatomic, and mapping variables on AF recurrence was analyzed. 160 patients (50.6% male, 1.3 pre-ablations, 60% persistent AF) with complete LA voltage maps were included. Mean follow-up time was 16 ± 11 months. Mean recorded electrograms (EGMs) per map were 9754 ± 5808, mean LA volume was 176.1 ± 35.9 ml and mean rate of LVAs <0.5 mV was 30.6% ± 23.1%. During follow-up recurrence rate of AF or AT>30 s was 55.6%. Patients with recurrence had a significant higher percentage of LVAs (40.0% vs. 18.8%, p < .001) but no relevant difference in LA volume (172 vs. 178 mL, p = .299). ROC curves revealed LVA as a good predictor for recurrence (AUC = 0.79, p < .001) and a cut-off of 22% LVAs with highest sensitivity (73.0%) and specificity (71.8%). Based on this cut off, event free survival was significantly higher in the Low LVA group (p < .01). Total LVA percentage has a good predictive power on arrhythmia recurrence in a cohort of advanced scarred left atria in repeat procedures independent of the applied ablation strategy. Left atrial volume seems to have minor impact on the rhythm outcome in our study cohort.

Impact of diabetes mellitus and poor glycemic control on the prevalence of left atrial low-voltage areas and rhythm outcome in patients with atrial fibrillation ablation.

Left atrial low-voltage areas (LVAs) are known to be correlated with atrial scarring and atrial fibrillation (AF) recurrence after ablation. However, the association between LVAs and glycemic status before ablation has not been fully clarified. The purpose of this study was to investigate associations among the prevalence of diabetes mellitus (DM), glycemic control, and the prevalence of LVAs in patients with AF ablation. In total, 912 (age, 68 ± 10 years; female, 299 [33%]; persistent AF, 513 [56%]) consecutive patients who underwent initial AF ablation were included. A preprocedure glycated hemoglobin A1c (HbA1c)≥7% was set as the cutoff for poor glycemic control in patients with DM. LVAs were defined as areas with a bipolar voltage of <0.5 mV covering ≥5 cm2 of left atrium. LVAs existed in 208 (23%) patients, and 168 (18%) patients had DM. LVAs were found more frequently in patients with DM and poor glycemic control. On multivariate analysis, DM with HbA1c≥7% was an independent predictor of LVAs (odds ratio, 3.3; 95% confidence interval: 1.6-6.7; p = .001). In patients with LVAs, freedom from AF recurrence during the 24-month study period was significantly lower in patients who had DM with HbA1c≥7% than in those without DM (37.9% vs. 54.7%, p = .02). In patients with AF ablation, LVAs were found more frequently in patients with DM and poor glycemic control. DM with HbA1c≥7% was an independent predictor of LVAs.

Association between left atrial low-voltage area and induction and recurrence of macroreentrant atrial tachycardia in pulmonary vein isolation for atrial fibrillation.

The relationship between induction and recurrence due to atrial tachycardia (AT) and left atrial (LA) matrix progression after atrial fibrillation (AF) ablation remains unclear. One hundred fifty-two consecutive patients with paroxysmal and persistent AF who underwent pulmonary vein isolation (PVI) and cavo-tricuspid isthmus (CTI) ablation and achieved sinus rhythm before the procedure were classified into three groups according to the AT pattern induced after the procedure: group N (non-induced), F (focal pattern), and M (macroreentrant pattern) in 3D mapping. The total rate of AT induction was 19.7% (30/152) in groups F (n = 13) and M (n = 17). Patients in group M were older than those in groups N and F, with higher CHADS2/CHA2DS2-VASc values, left atrial enlargement, and low-voltage area (LVA) size of LA. The receiver operating characteristic curve determined that the cut-off LVA for macroreentrant AT induction was 8.8 cm2 (area under the curve [AUC]: 0.86, 95% confidence interval [CI]: 0.75-0.97). The recurrence of AT at 36months in group N was 4.1% (5/122), and at the second ablation, all patients had macroreentrant AT. Patients with AT recurrence in group N had a wide LVA at the first ablation, and the cut-off LVA for AT recurrence was 6.5 cm2 (AUC 0.94, 95%CI 0.88-0.99). Adjusted multivariate analysis showed that only LVA size was associated with the recurrence of macroreentrant AT (odds ratio 1.21, 95%CI 1.04-1.51). It is important to develop a therapeutic strategy based on the LVA size to suppress the recurrence of AT in these patients.

Left Atrial Low Voltage Areas Predicts Recurrence of Atrial Fibrillation after Catheter Ablation: A Meta-Analysis.

Low voltage areas (LVAs) on left atrial (LA) voltage mapping correlate with atrial fibrosis. However, there is no uniform standard for the definition of LVAs, or mapping techniques and mapping rhythms, so that the predictive value of left atrial LVAs for recurrence of atrial fibrillation (AF) is uncertain. This study aimed to explore the relationship between the presence of pre-ablation left atrial LVAs and the risk of recurrent AF after catheter ablation. The databases of PubMed, Embase, Web of science, Cochrane library, Scopus, Wanfang Datebase, China National Knowledge Infrastructure, China Biology Medicine and China Scientific Journal Datebase were searched from inception to 31 July 2023. Relevant studies regarding left atrial LVAs prior to ablation to predict postoperative recurrence of AF were identified and analyzed. The efficacy endpoints were defined as the recurrence of atrial arrhythmia lasting over 30 s. A total of 12 studies with 1070 patients were included. We found the presence of pre-ablation left atrial LVAs correlated with the risk of recurrent AF after ablation (hazard ratio (HR) = 2.87, 95% confidence interval (CI): 2.33-3.52). The presence of pre-ablation left atrial LVAs can predict the risk of recurrent AF after ablation both in the follow-up duration ≤12 months group and follow-up duration >12 months group (follow-up duration ≤12 months: HR = 2.93, 95% CI: 2.20-3.90; follow-up duration >12 months: HR = 2.80, 95% CI: 2.09-3.77). The presence of pre-ablation left atrial LVAs correlated with the risk of recurrent AF after ablation in paroxysmal AF (HR = 2.89, 95% CI: 1.97-4.24). The presence of pre-ablation left atrial LVAs correlate with the risk of recurrent AF after catheter ablation.

Prognostic impact of atrial cardiomyopathy: Long-term follow-up of patients with and without low-voltage areas following atrial fibrillation ablation

BackgroundAtrial cardiomyopathy is known as an underlying pathophysiological factor in the majority of patients with atrial fibrillation (AF). Left atrial low-voltage areas (LVAs) are reported to coincide with fibrosis and likely represent atrial cardiomyopathy. ObjectiveThe purpose of this study was to delineate differences in the long-term prognosis of patients stratified by the size of LVAs. MethodsThis observational study included 1488 consecutive patients undergoing initial ablation for AF. LVAs were defined as regions with a bipolar peak-to-peak voltage <0.50 mV. The total study population was divided into 3 groups stratified by LVA size: patients with no LVAs (n = 1136); those with small (<20 cm2) LVAs (n = 250) LVAs; and those with extensive (≥20 cm2) LVAs (n = 102). Composite endpoints of death, heart failure, and stroke were followed for up to 5 years. ResultsComposite endpoints developed in 105 of 1488 patients (7.1%), and AF recurrence occurred in 410 (27.6%). Composite endpoints developed more frequently in the order of patients with extensive LVAs (19.1%), small LVAs (10.8%), and no LVAs (5.1%) (P for trend <.0001). Multivariable analysis revealed that LVA presence was independently associated with higher incidence of composite endpoints, irrespective of AF recurrence (modified hazard ratio 1.73; 95% confidence interval 1.13–2.64; P = .011) ConclusionLVA presence and its extent both were associated with poor long-term composite endpoints of death, heart failure, and stroke, irrespective of AF recurrence or other confounders. Underlying atrial cardiomyopathy seems to define a poor prognosis after AF ablation.

Left Atrial Low-Voltage Areas Predict the Risk of Atrial Fibrillation Recurrence after Radiofrequency Ablation.

Atrial fibrillation (AF), the most frequently encountered arrhythmia worldwide, is associated with increased cardiovascular morbidity and mortality. Left atrial (LA) and antral region of the pulmonary veins (PVs) remodeling are risk factors for AF perpetuation. Among the methods of LA fibrosis quantification, bipolar voltage mapping during three-dimensional electro-anatomical mapping is less studied. The main aim of this study was to analyze the relationship between the degree of LA fibrosis quantified in low-voltage areas and the efficacy of AF radiofrequency catheter ablation. All consecutive patients with AF ablation were included, and the degree of LA fibrosis was measured based on the low-voltage areas in the LA and the antral region of PVs (<0.5 mV for patients in sinus rhythm and <0.25 mV for patients in AF at the time of the ablation procedure). The efficacy of AF ablation was determined by the rate of recurrence after a blanking period of three months. A total of 106 patients were included; from these, 38 (35.8%) had AF recurrence after RF ablation, while 68 (64.2%) were free of events. The area and percentage of LA fibrosis were significantly higher in the patients with AF recurrence (p = 0.018 and p = 0.019, respectively). However, no significant differences were found between the patients with and without AF recurrence in terms of the area and percentage of PVs fibrosis (p = 0.896 and p = 0.888, respectively). Moreover, LA fibrosis parameters proved to be excellent predictors for AF recurrence (areas under the curve of 0.834 and 0.832, respectively, p < 0.001) even after adjustment for LA indexed volume and CHA2DS2-VASc score. In conclusion, LA fibrosis measured on bipolar voltage maps increases the risk of AF recurrence after the RF catheter ablation procedure.

Ratio of P-Wave Duration to P-Wave Amplitude and Left Atrial Remodeling: Insights from Electrophysiological Findings and Myocardial Injury After Cryoballoon Ablation

The impact of the P-wave morphology on clinical outcomes post-catheter ablation (CA) and recurrent arrhythmia characteristics or electrophysiological findings in paroxysmal atrial fibrillation (PAF) patients remains unclear. PAF patients who underwent cryoballoon ablation were enrolled. In twelve-lead electrocardiography recorded within one-month before CA, the P-wave duration (Pd) and P-wave vector magnitude (Pvm) (square root of the sum of the squared P-wave amplitude in leads II, V6 and one-half of the P-wave amplitude in V2) were measured and divided into two groups; patients with high and low Pd/Pvm based on a statistically calculated cut-off value. We evaluated the incidence of late recurrence of AF (LRAF), myocardial injury (high-sensitive troponin I [hs-TnI]) and the electrophysiological findings in repeat ablation sessions. This study included 269 PAF patients. The median follow-up duration was 697 days. The cut-off value of the Pd/Pvm for predicting LRAF was 740.7ms/mV (AUC=0.81, sensitivity=58.2% and specificity=89.6%). Multivariable Cox proportional hazards analysis showed high Pd/Pvm (>740.7ms/mV) was significantly associated with LRAF (p<0.001). The hs-TnI level was significantly lower and ratio of DR-FLASH score>3 significantly higher in those with high than low Pd/Pvm (p=0.044, p=0.002, respectively). In the repeat ablation sessions, the Pd/Pvm in patients with atrial tachycardia (AT) induced or spontaneously occurring during the repeat CA sessions was significantly higher than in those without (p=0.009). There was a significant difference between the Pd/Pvm and low-voltage area (LVA) (p<0.001). In conclusion, the Pd/Pvm is significantly associated with LRAF after cryoballoon ablation in PAF patients and predicts left atrial LVAs and AT inducibility.

Poor glycemic control is associated with the prevalence of left atrial low-voltage areas in patients with atrial fibrillation ablation

Abstract Background Although glycemic control before atrial fibrillation (AF) ablation is associated with AF recurrence after the procedure, the mechanism has not been fully clarified. Left atrial low-voltage areas (LVAs) were known to be correlated with atrial scarring and AF recurrence after ablation, and a preliminary study showed that the past history of diabetes mellitus (DM) was an independent predictor of LVAs. However, the association between LVAs and glycemic control before ablation has not been elucidated. Purpose The purpose of this study was to investigate the association between glycemic control before AF ablation and the prevalence of LVAs in patients with AF ablation. Methods The study design was a single center, retrospective observational study. Between December 2014 and December 2018, 782 (age, 68 ± 10 years; female, 262 [34%]; persistent AF, 414 [53%]) consecutive patients who underwent initial AF ablation were included. Glycated hemoglobin A1c (HbA1c) levels were measured before the procedure, and HbA1c ≥ 7% was set as the cut-off value of poor glycemic control in patients with DM. The definition of LVAs was sites with a left atrial bipolar amplitude &amp;lt; 0.5 mV covering as ≥ 5 cm². Rhythm outcome after the procedure was followed for 24 months. Results Of 782 patients, 162 (21%) patients had LVAs, and 135 (17%) patients had past history of DM. LVAs were found more frequently in patients with poor glycemic control (Figure 1). On multivariate analysis, DM with HbA1c ≥7% was an independent predictor of LVAs (odds ratio, 3.6; 95% confidence interval: 1.8–7.0; p &amp;lt; 0.001). In patients with LVAs, freedom from AF recurrence during the study periods tended to be lower in patients who had DM with HbA1c ≥7% than in those with non-DM (40.3% versus 51.6%, p = 0.06) (Figure 2). Conclusions In patients with AF ablation, LVAs were found more frequently in patients with poor glycemic control. In particular, DM with HbA1c ≥7% was an independent predictor of LVAs.Prevalence of LVAs and glycemic controlAF recurrence and glycemic control

Abstract 17728: Distribution and Predictors of Left Atrial Low Voltage Areas in Patients With Atrial Fibrillation Undergoing Catheter Ablation

Background: Low voltage areas (LVAs) in the left atrium (LA) are associated with a higher likelihood of non-pulmonary vein triggers for atrial fibrillation (AF), and ablation of LVAs has been shown to reduce AF recurrence. This study aimed to assess the distribution and predictors of LVAs in a large cohort of patients undergoing AF ablation. Methods: This study included patients who underwent first AF ablation at the Hospital of the University of Pennsylvania between November 2020 and December 2022. Patients with prior LA ablation, cardiac surgery, sarcoidosis, or amyloidosis were excluded. All patients underwent voltage mapping with multipolar mapping catheters and pulmonary vein isolation. LVAs were defined as contiguous areas with a bipolar voltage &lt;0.5mV. The associations between preprocedure risk factors, echocardiographic findings, and LVAs were assessed using univariable logistic regression. All variables with a p value &lt;0.1 were entered in a stepwise, backward, multivariable model. Results: A total of 857 consecutive patients (mean age: 64.7 years, 34% women, 33% non-paroxysmal AF) were included. LVAs were identified in 132 (15.4%) patients, of whom 72% had LVAs in posterior wall, 47.7% in roof/anterior, 43.9% in septum, 24.2% in floor/inferior, and 16.7% in lateral wall. The multivariable model showed that age (OR per 1 year increase 1.05, 95% CI 1.03-1.08), heart failure/left ventricular cardiomyopathy (OR 2.1, 95% CI 1.4-3.3), sinus node dysfunction (OR 3.7, 95% CI 1.8-7.3), persistent/permanent AF (OR 3.2, 95% CI 2.1-4.9), and severe LA enlargement on echocardiography (OR 1.9, 95% CI 1.1-3.5) were independent predictors of LVAs. Conclusion: LVAs are identified in 15% of patients undergoing first AF ablation and are typically located along the posterior and anteroseptal LA. Presence of LVAs can be anticipated using a readily available preprocedure risk assessment. This information may influence preprocedure planning and choice of ablation strategy.

P-wave duration-amplitude ratio quantifies atrial low-voltage area and predicts atrial arrhythmia recurrence following pulmonary vein isolation.

Atrial low-voltage area (LVA) in AF patients increase the risk of atrial arrhythmia (AA) recurrence following pulmonary vein isolation (PVI). Contemporary LVA prediction scores (DR-FLASH, APPLE) do not include P-wave metrics. We aimed to evaluate the utility of P-wave duration-amplitude ratio (PWR) in quantifying LVA and predicting AA recurrence post-PVI. In 65 patients undergoing first-time PVI, 12-lead ECGs were recorded during sinus rhythm. PWR was calculated as the ratio between the longest P-wave duration and P-wave amplitude in lead I. High-resolution bi-atrial voltage maps were collected and LVAs included bipolar electrogram amplitudes <0.5mV or <1.0mV. A LVA quantification model was created using clinical variables and PWR, then validated in a separate cohort of 24 patients. Seventy-eight patients were followed for 12-months to evaluate AA recurrence. PWR strongly correlated with left atrial (LA) (<0.5mV: r=0.60; <1.0mV: r=0.68; p<0.001) and bi-atrial LVA (<0.5mV: r=0.63; <1.0mV: r=0.70; p<0.001). Addition of PWR to clinical variables improved model quantification of LA LVA at the <0.5mV (adjusted R2: 0.59 to 0.68) and <1.0mV cutpoints (adjusted R2: 0.59 to 0.74). In the validation cohort, PWR model-predicted LVA correlated strongly with measured LVA (<0.5mV: r=0.78; <1.0mV: r=0.81; p<0.001). PWR model was superior to DR-FLASH (AUC 0.90 vs. 0.78; p=0.030) and APPLE (AUC 0.90 vs. 0.67; p=0.003) at detecting LA LVA and comparable at predicting AA recurrence post-PVI (AUC=0.67 vs. 0.65 and 0.60). Our novel PWR model accurately quantifies LVA and predicts AA recurrence post-PVI. PWR model-predicted LVA may help guide patient selection for PVI.

Comparing Left Atrial Low Voltage Areas in Sinus Rhythm and Atrial Fibrillation Using Novel Automated Voltage Analysis: A Pilot Study.

Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26. We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS. Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall.