Pulmonary vein antrum isolation leads to a significant decrease of left atrial size

Early Remodeling of the Left Atrium Following Catheter Ablation of Atrial Fibrillation: Insights From DECAAFII

BACKGROUND

Left atrial (LA) enlargement is prevalent among atrial fibrillation (AF) patients and constitutes an important marker of atrial myopathy. Several studies have described reduction in LA volume post-catheter ablation (CA) of AF, however, none have investigated differences related to additional ablation outside the pulmonary veins (PVs).

OBJECTIVES

The authors sought to study early LA remodeling following CA of persistent AF and the impact of additional, fibrosis-guided extra-PV ablation.

METHODS

In this DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial subanalysis, patients with persistent AF were randomized to receive pulmonary vein isolation (PVI) only or PVI + fibrosis-guided ablation. Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) was performed before and 3 months after CA. Patients were followed up with single-lead electrocardiogram devices for 12 to18 months. AF burden was calculated as days with AF divided by days monitored.

RESULTS

This analysis included 733 patients. The mean LA volume index (LAVI) before ablation was 62.0 mm3/m2 and after ablation was 51.3 mm3/m2, with a mean reduction of 10.7 mm3/m2 (P < 0.001). Patients in the fibrosis-guided ablation arm had more volume reduction than did those in the PVI-only group (12.1 mm3/m2 vs 9.3 mm3/m2; P = 0.02). LAVI reduction was greater in patients with heart failure (15.7 vs 8.9; P = 0.001) and was associated with improved left ventricular ejection fraction (LVEF) (r = 0.23; P < 0.001), reduced AF burden (r = -0.173; P < 0.001), improved LVEF, and improved quality of life (r = 0.146; P < 0.001).

CONCLUSIONS

We confirmed the presence of LA remodeling within 3 months after ablation for persistent AF. Importantly, we saw more LA volume reductions in patients in the PVI + fibrosis-guided ablation arm in comparison with PVI only, and in patients with LV dysfunction. LA volume reduction in response to CA is associated with decreased arrhythmia recurrence, reduced AF burden, and improved LVEF and quality of life.

A failed catheter ablation of atrial fibrillation is associated with more advanced remodeling and reduced efficacy of further thoracoscopic ablation

INTRODUCTION AND OBJECTIVES

Recent observations suggest that patients with a previous failed catheter ablation have an increased risk of atrial fibrillation (AF) recurrence after subsequent thoracoscopic AF ablation. We assessed the risk of AF recurrence in patients with a previous failed catheter ablation undergoing thoracoscopic ablation.

METHODS

We included patients from 3 medical centers. To correct for potential heterogeneity, we performed propensity matching to compare AF freedom (freedom from any atrial tachyarrhythmia> 30 s during 1-year follow-up). Left atrial appendage tissue was analyzed for collagen distribution.

RESULTS

A total of 705 patients were included, and 183 had a previous failed catheter ablation. These patients had fewer risk factors for AF recurrence than ablation naïve controls: smaller indexed left atrial volume (40.9± 12.5 vs 43.0±12.5 mL/m², P=.048), less congestive heart failure (1.5% vs 8.9%, P=.001), and less persistent AF (52.2% vs 60.3%, P=.067). However, AF history duration was longer in patients with a previous failed catheter ablation (6.5 [4-10.5] vs 4 [2-8] years; P<.001). In propensity matched analysis, patients with a failed catheter ablation were at a 68% higher AF recurrence risk (OR, 1.68; 95%CI, 1.20-2.15; P=.034). AF freedom was 61.1% in patients with a previous failed catheter ablation vs 72.5% in ablation naïve matched controls. On histology of the left atrial appendage (n=198), patients with a failed catheter ablation had a higher density of collagen fibers.

CONCLUSIONS

Patients with a prior failed catheter ablation had fewer risk factors for AF recurrence but more frequently had AF recurrence after thoracoscopic AF ablation than ablation naïve patients. This may in part be explained by more progressed, subclinical, atrial fibrosis formation.

Early Rhythm Control in Patients With Incident Atrial Fibrillation Who Had a Prior Stroke

BACKGROUND

There are limited data regarding the benefit of early rhythm control therapy for secondary prevention for stroke in patients with atrial fibrillation (AF).

OBJECTIVES

This study aimed to compare the risk of recurrent stroke between early rhythm control therapy and usual care in patients with new-onset AF and a history of prior stroke.

METHODS

Using the Korean nationwide claims database, the investigators identified patients who were newly diagnosed with AF and had a history of prior stroke. Patients who received rhythm control therapy, including antiarrhythmic drug, direct current cardioversion, or AF catheter ablation, within 1 year after incident AF were defined as the early rhythm control group, and the others were the usual care group. The propensity score weighting method was used to balance baseline characteristics between the 2 groups. Incident stroke was evaluated as a primary outcome.

RESULTS

A total of 53,509 patients were included (12,455 in the early rhythm control group and 41,054 in the usual care group). All patients were prescribed oral anticoagulants. During a median 2.6 years of follow-up, 4,382 patients had an incident stroke (incidence rate: 2.6 per 100 person-years). Early rhythm control was associated with a lower risk of recurrent stroke compared to the risk associated with usual care (weighted HR: 0.720; 95% CI: 0.666-0.779; P < 0.001).

CONCLUSIONS

Early rhythm control within 1 year after AF diagnosis might be beneficial to prevent recurrent stroke in patients with incident AF and a history of stroke. Integrated care, including optimal rhythm control with appropriate anticoagulation, should be considered in this population.

Intra- and Postprocedural Multimodality Imaging in Atrial Fibrillation

Multi-modality imaging plays critical roles during and after procedures associated with atrial fibrillation. Transesophageal echocardiography is an invaluable tool for left atrial appendage occlusion during the procedure and at follow-up. Both cardiac computed tomography and cardiac magnetic resonance contribute to postprocedural evaluation of pulmonary vein isolation ablation. The present review is the second of a 2-part series where we discuss the roles of cardiac imaging in the evaluation and management of patients with atrial fibrillation, focusing on intraprocedural and postprocedural assessment, including the clinical evidence and outcomes data supporting this future applications.

Reduction of Atrial Septal Defect Size After Catheter Ablation for Atrial Tachyarrhythmia and Its Predictive Factors

The prevalence of atrial tachyarrhythmia is high in patients with atrial septal defect (ASD), and catheter ablation (CA) is often performed before percutaneous ASD closure. We aimed to clarify the effect of CA on the ASD size. We analysed 16 patients with secundum ASD who had a history of CA for atrial tachyarrhythmia and underwent ASD size evaluation before and after CA. The size of ASD significantly decreased after CA. Younger age and lower tricuspid regurgitation pressure gradients and pulmonary arterial systolic pressures were associated with size reduction. These factors are crucial for making strategies of percutaneous ASD closure.

Cardiac resynchronization therapy in the presence of total atrioventricular block reduces long‐lasting atrial fibrillation episodes

Background

There is an ongoing debate on how cardiac resynchronization therapy (CRT) in the presence of total AV block affects atrial fibrillation (AF) episodes and symptoms in patients with AF.

Methods

Seventy‐five patients with symptomatic, drug and ablation refractory AF received, irrespective of their left ventricular ejection fraction (EF), either a CRT device and underwent subsequent atrioventricular node (AVN) ablation or already had a total AV block and underwent CRT upgrade. Long‐lasting AF episodes (>48 h), left ventricular ejection fraction (LVEF), left ventricular end‐diastolic diameter (LVEDD), left atrial diameter (LAD), NTproBNP levels, EHRA score, and NYHA class had been monitored on the follow‐up.

Results

The number of patients experiencing long‐lasting AF episodes (>48 h) and symptoms decreased significantly within 24 months after CRT implantation in the presence of total AV block (p < .001) from 57 (76%) to 25 (33.3%). Mean LAD decreased from 52 mm (IQR 48.0–56.0) to 48 mm (IQR 42.0–52.0, p < .001) and LVEDD from 54 mm (IQR 49.0–58.0) to 51 mm (IQR 46.5–54.0, p < .001).

Conclusion

A combination of total AVN block and biventricular pacing markedly reduces long‐lasting AF episodes, symptoms, left atrial diameter, and left ventricular end‐diastolic diameter.

Impact of radiofrequency catheter ablation for atrial fibrillation in patients with left atrial enlargement

Little has been reported on the impact of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) in patients with left atrial enlargement (LAE). A total of 706 patients underwent an initial RFCA for AF between September 2014 and September 2019 in our hospital. These patients were categorized into two groups according to the pre-procedural left atrial diameter (LAD) measured by transthoracic echocardiography (TTE): LAE group with LAD ≥ 50 mm and non-LAE group with LAD < 50 mm. We compared the patient characteristics, ablation procedures, and late recurrence of AF (LRAF, defined as a recurrence of atrial tachyarrhythmia between 3 and 12 months after the RFCA) between the two groups. In addition, we performed follow-up TTE at 12 months after RFCA and investigated the factors associated with left atrium (LA) reverse remodeling in each group. LAE group and non-LAE group consisted of 155 and 551 patients, respectively. There were no significant differences in ablation procedures, procedure-related complications, and the incidence of LRAF between the two groups. Furthermore, non-PAF was identified as an independent predictor of LA reverse remodeling in LAE group by multiple regression analysis (P = 0.020). RFCA might be an effective and safe procedure even in patients with LAD ≥ 50 mm, using the contemporary 3D-guided mapping and ablation technologies. Moreover, RFCA can lead to LA reverse remodeling in 1 year if they have non-PAF before ablation.

Restoring Sinus Rhythm Reverses Cardiac Remodeling and Reduces Valvular Regurgitation in Patients With Atrial Fibrillation

BACKGROUND

Cardiac chamber remodeling in atrial fibrillation (AF) reflects the progression of cardiac rhythm and may affect functional regurgitation.

OBJECTIVES

The purpose of this study was to explore the 3-dimensional echocardiographic variables of cardiac cavity remodeling and the impact on functional regurgitation in patients with AF with/without sinus rhythm restoration at 12 months.

METHODS

A total of 117 consecutive patients hospitalized for AF were examined using serial 3-dimensional transthoracic echocardiography at admission, at 6 months, and at 12 months (337 examinations).

RESULTS

During follow-up, 47 patients with active restoration of sinus rhythm (SR) (through cardioversion and/or ablation) had a decrease in all atrial indexed volumes (Vi), end-systolic (ES) right ventricular (RV) Vi, an increase in end-diastolic (ED) left ventricular Vi, and an improvement in 4-chambers function (P < 0.05). Patients with absence/failure of restoration of SR (n = 39) had an increase in ED left atrial Vi and ED/ES RV Vi without modification of 4-chambers function, except for a decrease in left atrial emptying fraction (P < 0.05). Patients with spontaneous restoration of SR (n = 31) had no changes in Vi or function. The authors found an improvement vs baseline in severity of functional regurgitation in patients with active restoration of SR (tricuspid and mitral regurgitation) and in spontaneous restoration of SR (tricuspid regurgitation) (P < 0.05). In multivariable analysis, right atrial and/or left atrial reverse remodeling exclusively correlated with intervention (cardioversion and/or ablation) during 12-month follow-up.

CONCLUSIONS

Management of AF should focus on restoration of SR to induce anatomical (all atrial Vi, ES RV Vi) and/or functional (4 chambers) cardiac cavity reverse remodeling and reduce severity of functional regurgitation. (Thromboembolic and Bleeding Risk Stratification in Patients With Non-valvular Atrial Fibrillation [FASTRHAC]; NCT02741349).

Atrial reverse remodeling represented by the atrial conduction time in persistent atrial fibrillation patients after catheter ablation: its impact on predicting late atrial fibrillation recurrence

BACKGROUND

The aim of this study was to examine the reduction in the atrial conduction time during the follow-up phase of catheter ablation in persistent atrial fibrillation (PsAF) patients, which would suggest atrial reverse remodeling, and to investigate its impact on predicting AF recurrence.

METHODS

Fifty-seven PsAF patients underwent radiofrequency catheter ablation. The P-wave to left atrial appendage (LAA) conduction time was measured by transthoracic echocardiography using tissue Doppler imaging (P-LAA TDI), within 24 h and 6 months after ablation.

RESULTS

The accuracy of the P-LAA TDI was confirmed by measuring the actual electrophysiological data during the ablation (90 ± 13 ms, r = 0.754, p < 0.001). The P-LAA TDI was significantly reduced (170 ± 18 msec to 159 ± 19 msec, p < 0.001) at the 6-month follow-up. Sixteen patients (28%) had an AF recurrence by 12 months of follow-up. The no-AF recurrence group had a significantly reduced P-LAA TDI 6 months later (165 ± 15 msec to 155 ± 18 msec, p < 0.001), while there was no significance in the AF recurrence group (184 ± 21 msec to 174 ± 16 msec, p = 0.091). The P-LAA TDI was a predictive factor of AF recurrence after ablation with a cut-off value of >175 msec (sensitivity = 0.750, specificity = 0.780) when measured within 24 h after ablation and >166 msec (sensitivity = 0.750, specificity = 0.756) when calculated at 6 months of follow-up.

CONCLUSIONS

In PsAF patients, a significant reduction in the P-LAA TDI was observed at 6 months of follow-up, which may have represented the occurrence of left atrial reverse remodeling. These findings suggested that the P-LAA TDI time in the follow-up was appropriate for predicting late AF recurrences.

Incidence and Predictors of Atrial Fibrillation Progression

Background The incidence and predictors of atrial fibrillation (AF) progression are currently not well defined, and clinical AF progression partly overlaps with rhythm control interventions (RCIs). Methods and Results We assessed AF type and intercurrent RCIs during yearly follow-ups in 2869 prospectively followed patients with paroxysmal or persistent AF. Clinical AF progression was defined as progression from paroxysmal to nonparoxysmal or from persistent to permanent AF. An RCI was defined as pulmonary vein isolation, electrical cardioversion, or new treatment with amiodarone. During a median follow-up of 3 years, the incidence of clinical AF progression was 5.2 per 100 patient-years, and 10.9 per 100 patient-years for any RCI. Significant predictors for AF progression were body mass index (hazard ratio [HR], 1.03; 95% CI, 1.01-1.05), heart rate (HR per 5 beats/min increase, 1.05; 95% CI, 1.02-1.08), age (HR per 5-year increase 1.19; 95% CI, 1.13-1.27), systolic blood pressure (HR per 5 mm Hg increase, 1.03; 95% CI, 1.00-1.05), history of hyperthyroidism (HR, 1.71; 95% CI, 1.16-2.52), stroke (HR, 1.50; 95% CI, 1.19-1.88), and heart failure (HR, 1.69; 95% CI, 1.34-2.13). Regular physical activity (HR, 0.80; 95% CI, 0.66-0.98) and previous pulmonary vein isolation (HR, 0.69; 95% CI, 0.53-0.90) showed an inverse association. Significant predictive factors for RCIs were physical activity (HR, 1.42; 95% CI, 1.20-1.68), AF-related symptoms (HR, 1.84; 95% CI, 1.47-2.30), age (HR per 5-year increase, 0.88; 95% CI, 0.85-0.92), and paroxysmal AF (HR, 0.61; 95% CI, 0.51-0.73). Conclusions Cardiovascular risk factors and comorbidities were key predictors of clinical AF progression. A healthy lifestyle may therefore reduce the risk of AF progression.

Prognostic significance of atrial fibrillation in acute decompensated heart failure with reduced versus preserved ejection fraction

OBJECTIVE

The prognostic impact of atrial fibrillation (AF) in patients with acute decompensated heart failure (ADHF) has not been fully elucidated yet. Aim of the present study was thus to investigate the association of AF with all-cause mortality in patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).

METHODS

We performed a retrospective single center study and analyzed data of 1286 patients admitted for ADHF. Patients were grouped according to AF status (i.e., "never AF", "history of AF", or "AF on admission") and type of heart failure. Patient and treatment characteristics were extracted by chart review. The primary outcome of all-cause mortality within 3 years following index hospitalization was determined by death registry linkage.

RESULTS

In total, 529 (41.1%), 215 (16.7%), and 542 (42.1%) patients were grouped as "never AF", "history of AF", and "AF on admission", respectively. With regard to type of heart failure, 558 (43.4%) and 728 (56.6%) had HFrEF and HFpEF, respectively. Compared to "never AF", "AF on admission" was associated with increased all-cause mortality in an adjusted Cox regression model [hazard ratio, 1.64 (95% confidence interval 1.32-2.04); P < 0.001]. However, this association remained significant only for patients with HFpEF [2.16 (1.58-2.95)], but not for patients with HFrEF [1.18 (0.85-1.63)] in a subgroup analysis (P for effect modification = 0.020).

CONCLUSIONS

AF is common in the setting of ADHF and is associated with increased all-cause mortality. However, this association remained significant only in patients with HFpEF, but not in patients with HFrEF.

Different Responses of Left Atrium and Left Atrial Appendage to Radiofrequency Catheter Ablation of Atrial Fibrillation: a Follow Up MRI study

Atrial fibrillation (AF) is known to cause adverse remodeling of left atrium (LA). Radiofrequency catheter ablation (RFCA) of AF is associated with decrease in LA volume. However, the impact of RFCA on left atrial appendage (LAA) volume and hemodynamic function is not fully understood. We analyzed 123 patients who underwent cardiac magnetic resonance imaging (MRI) evaluation before and after RFCA in Korea University Anam Hospital. LA and LAA volume were measured before and after RFCA based on cardiac MRI. Baseline LA volume was 99.5 ± 38.4 cm³ and decreased to 74.6 ± 28.5 cm³ after RFCA (p < 0.001). LA diameter measured with transthoracic echocardiography was also decreased after RFCA (43.3 ± 6.2 mm at baseline and 39.9 ± 5.9 mm at follow up; p < 0.001). However, LAA volume was significantly increased after RFCA (19.4 ± 8.5 cm³ at baseline and 23.7 ± 13.3 cm³ at follow up; p < 0.001). Total ablation time and additional substrate modification was associated with change in LA volume. After RFCA, average LAA velocity measured by transesophageal echocardiography was increased to 51.0 cm/sec from 41.1 cm/sec (p < 0.001). In conclusion, LAA volume was increased after RFCA in contrast to LA volume. Our data raise a concern about worsening hemodynamics of LA and LAA following RFCA and long term clinical significance of enlarged LAA after RFCA needs further evaluation.

Active Atrial Function and Atrial Scar Burden After Multiple Catheter Ablations of Persistent Atrial Fibrillation

BACKGROUND

Extensive and repeated substrate modification (SM) is frequently performed as an ablation strategy in persistent atrial fibrillation (persAF). The effect of these extended ablation strategies on atrial function has not been investigated sufficiently so far. The purpose was to assess atrial function by cardiac magnetic resonance (CMR) and its association with left atrial (LA) scar burden by electroanatomical voltage-mapping after multiple persAF ablation procedures.

METHODS

We included 16 persAF patients who had ≥2 SM procedures and a control group (CG) of 21 persAF patients without prior ablation. CMR was performed in sinus rhythm at least 4 weeks after the last cardioversion. Active left and right (RA) atrial emptying fractions (AEF) as well as peak active left atrial appendage (LAA) emptying velocities were obtained by CMR flow measurements. Furthermore, LA scar burden was quantified on electroanatomical voltage maps by the portion of points with local voltage amplitude <0.2 mV.

RESULTS

We found median LA-AEF to be lower (13 [9-22] vs 32 [26-36] %, P < 0.001) and median LA scar burden to be higher (40 [20-68] vs nine [3-18] %, P < 0.05) in the SM group compared with the CG. Furthermore, a significant correlation was found between mean LA voltage and LA-AEF (r² = 0.62, P < 0.001). No significant differences were detected with respect to median RA-AEF (41 [28-48] vs 47 [35-50] %, P = 0.43) and median peak LAA emptying velocities (30 [16-40] vs 17 [13-28] cm/s, P = 0.07).

CONCLUSIONS

Active LA function is preserved but significantly impaired and associated with ablation-related LA scar burden after multiple extensive persAF ablations.

Reversal of pulmonary vein remodeling after catheter ablation of atrial fibrillation

Background

Pulmonary veins (PV) and the atria undergo electrical and structural remodeling in atrial fibrillation (AF). This study aimed to determine PV and left atrial (LA) reverse remodeling after catheter ablation for AF assessed by chest computed tomography (CT).

Methods

PV electrophysiologic studies and catheter ablation were performed in 63 patients (68% male; mean ± SD age: 56 ± 10 years) with symptomatic AF (49% paroxysmal, 51% persistent). Chest CT was performed before and 3 months after catheter ablation.

Results

At baseline, patients with persistent AF had a greater LA volume (91 ± 29 cm³vs. 66 ± 27 cm³; P = 0.003) and mean PV ostial area (241 ± 43 mm²vs. 212 ± 47 mm²; P = 0.03) than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients (76%) were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume (77 ± 31 cm³ to 70 ± 28 cm³; P < 0.001) and mean PV ostial area (224 ± 48 mm² to 182 ± 43 mm²; P < 0.001). Patients with persistent AF had more reduction in LA volume (11.8 ± 12.8 cm³vs. 4.0 ± 11.2 cm³; P = 0.04) and PV ostial area (62 mm²vs. 34 mm²; P = 0.04) than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume (r = 0.38, P = 0.03).

Conclusions

Catheter ablation of AF improves structural remodeling of PV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.

The Convergent Procedure - A Standardised and Anatomic Approach Addresses the Clinical and Economic Unmet Needs of the Persistent Atrial Fibrillation Population

A standardised treatment management approach is needed to address the escalating worldwide prevalence of atrial fibrillation (AF). The persistent and longstanding persistent AF patient population particularly needs this standardised treatment option to manage their AF. These patients have underlying structural heart disease that result in increased hospitalizations, long-term medical management that increases the cost burden of the healthcare system. Approximately 100 patients have undergone the Convergent Procedure at our center since its introduction 2 years ago, as a treatment option for AF patients. The epicardial and endocardial ablation procedures performed sequentially in a single setting has shown a single procedure success rate of 80%, similar to published success rates at other centers. The epicardial posterior wall isolation silences a majority of known substrates and the endocardial procedure completes the pulmonary vein isolation, creates the cavotricuspid line and provides diagnostic confirmation. The Convergent Procedure should be considered as a first line treatment option for the persistent and longstanding persistent AF patient population who have very limited or no treatment options for the long-term successful management of their AF.

Study on Left Atrial Dimension and Function After Modified Endoscopic Procedure for Atrial Fibrillation at Two Years' Follow-Up

BACKGROUND

Modified endoscopic procedures for atrial fibrillation (AF) have a greater success rate because of the increased number of linear lesions. Concerns have been raised about the impact of ablation scars on the left atrium. This study aimed to examine the impact of ablation on left atrial dimension and systolic function after modified endoscopic procedures with echocardiographic measurement.

METHODS

Of 107 patients undergoing modified endoscopic ablation, 58 had paroxysmal AF and 49 had persistent or long-standing AF. The procedure was performed on the beating heart through three ports on the left chest wall. Three circular and two linear lesions were made on the left atrium. The left atrial appendage was excised by stapler. Echocardiography was performed preoperatively and at the 2-year follow-up.

RESULTS

Most patients (86.9%) patients were in sinus rhythm (SR) postoperatively. Fourteen patients (5 with paroxysmal AF and 9 with persistent/long-standing AF) failed to maintain SR. Echocardiographic data indicated that the left atrial diameter decreased only in the patients with postoperative SR but continued to increase in patients with fail SR maintenance. Left atrial function was also improved after the procedure, especially in patients with preoperative nonparoxysmal AF or with postoperative SR maintenance. Furthermore, left atrial function in patients who failed to restore SR was not worsened even with left atrial appendage excision.

CONCLUSIONS

Modified endoscopic procedure for AF improved post-procedural left atrial function of patients with SR maintenance. The left atrial function of patients with failed SR maintenance was also not worsened after left atrial appendage excision.

Surgical Left Atrial Appendage Exclusion Does Not Impair Left Atrial Contraction Function: A Pilot Study

Background. In order to reduce stroke risk, left atrial appendage amputation (LAAA) is widely adopted in recent years. The effect of LAAA on left atrial (LA) function remains unknown. The objective of present study was to assess the effect of LAAA on LA function. Methods. Sixteen patients with paroxysmal AF underwent thoracoscopic, surgical PVI with LAAA (LAAA group), and were retrospectively matched with 16 patients who underwent the same procedure without LAA amputation (non-LAAA group). To objectify LA function, transthoracic echocardiography with 2D Speckle Tracking was performed before surgery and at 12 months follow-up. Results. Mean age was 57 ± 9 years, 84% were male. Baseline characteristics did not differ significantly except for systolic blood pressure (p = 0.005). In both groups, the contractile LA function and LA ejection fraction were not significantly reduced. However, the conduit and reservoir function were significantly decreased at follow-up, compared to baseline. The reduction of strain and strain rate was not significantly different between groups. Conclusions. In this retrospective, observational matched group comparison with a convenience sample size of 16 patients, findings suggest that LAAA does not impair the contractile LA function when compared to patients in which the appendage was unaddressed. However, the LA conduit and reservoir function are reduced in both the LAAA and non-LAAA group. Our data suggest that the LAA can be removed without late LA functional consequences.

Prognostic Implications of Right and Left Atrial Enlargement after Radiofrequency Catheter Ablation in Patients with Nonvalvular Atrial Fibrillation

Background and Objectives

The prognostic role of the right atrium (RA) compared with that of the left atrium (LA) is unclear in patients with atrial fibrillation (AF). We assessed structural changes in both atria and determined their association with recurrence of AF after radiofrequency catheter ablation (RFCA).

Subjects and Methods

All 111 patients with nonvalvular AF (87 men; mean age, 57±11 years; 68 with paroxysmal AF) who underwent RFCA were enrolled consecutively. Three-dimensional volumes of both atria measured from computed tomography images were compared between subjects with and without recurrence of AF during the follow-up.

Results

Early (<3 months), 6-month, and 1-year recurrence was documented in 26 (24%), 30 (27%), and 36 (32%) patients, respectively. Significantly larger RA and LA volume indices (RAVI and LAVI) were observed in the early, 6-month, and 1-year recurrence groups (p<0.05 for all). In multivariate analysis, Early recurrence was independently associated with RAVI (for each 10 mL/m2 increase; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.03-1.66, p= 0.03), but not with LAVI. However, both RAVI and LAVI failed to predict 6-month outcomes independently. LAVI was the only independent predictor of 1-year recurrence (for each 10 mL/m2 increase; OR, 1.36; 95% CI, 1.08-1.71, p=0.009).

Conclusion

RA enlargement was more closely related to early recurrence of AF after RFCA than LA size. However, LA size, rather than RA volume, was a determinant of long-term AF prognosis after RFCA. These findings suggest a temporal pattern in the prognostic implication of enlargement in each atrium that switches over time after RFCA for AF.

Role of magnetic resonance imaging in atrial fibrillation ablation

OPINION STATEMENT

Ablation therapy is widely used for treatment of drug-resistant atrial fibrillation (AF). Ablation success for AF, however, is relatively low, often requiring repeated procedures for long-term suppression of the arrhythmia. Utilization of imaging techniques that visualize cardiac anatomy, function, and tissue characteristics may improve ablation results. Compared to other imaging modalities, cardiac magnetic resonance (CMR) has several advantages, including the lack of ionizing radiation and unsurpassed soft tissue resolution. Chamber morphology images can be registered onto electroanatomic maps acquired during the procedure, thus improving procedural safety and efficacy. In addition, the ability of CMR to characterize myocardial tissues may optimize patient selection for ablation and thromboembolic risk stratification. Post-procedure CMR can be used to detect potential complications, and with improved resolution, it has the potential to assess the integrity of ablation lesions. In this paper we will review the role of CMR in the pre-ablation diagnostic workup of AF patients as well as during and after catheter ablation.

Updating the evidence for the effect of radiofrequency catheter ablation on left atrial volume and function in patients with atrial fibrillation: a meta-analysis

Objectives

To systematically review the effects of radiofrequency catheter ablation (RFCA) on left atrial (LA) size, volumes and function in patients with atrial fibrillation (AF).

Methods

We searched MEDLINE, EMBASE, ScienceDirect, Highwire, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and the reference lists of retrieved reports in July 2012.

Setting

China

Participants

Twenty-six studies (enrolling 1821 patients) were included in the final analysis.

Main outcome measures

Changes of LA size or volumes and/or function in patients with AF after RFCA.

Results

Compared to pre-ablation values, there were significant decreases in LA diameter and LA volumes at post-ablation follow-up. However, compared to pre-ablation values, there were no significant differences in LA ejection fraction/LA active emptying fraction and LA strain at post-ablation follow-up. Decreases in LA diameter and LA volumes remained significant in those without AF recurrence but not in those with AF recurrence. LA ejection fraction/LA active emptying fraction did not decrease in patients without AF recurrence, whereas they decreased in patients with AF recurrence. As for LA strain, it seems that LA strain increases in patients without AF recurrence, with less fibrosis and with more LA volumes decrease, but the differences were not significant.

Conclusions

Successful RFCA in patients with AF significantly decreases LA size and volumes and does not seem to adversely affect LA function.

Impact of pulmonary vein antrum isolation on left atrial size and function in patients with atrial fibrillation

PURPOSE

The success of PVAI in eliminating AF has been proven; however, its impact on the LA remains uncertain. This study aimed to determine the impact of pulmonary vein antrum isolation (PVAI) on left atrial (LA) size and function in patients with atrial fibrillation (AF).

METHODS

Consecutive patients with AF were included (n = 206). Magnetic resonance imaging (MRI) was performed before and after PVAI in all patients. A subgroup (n = 52) underwent delayed enhancement MRI. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) were assessed by Simpson's rule. LA function was determined by calculating LA ejection fraction (LA EF). LA fibrosis was manually encircled and summed in the region of interest.

RESULTS

Single procedure success rate was 64 %. LAVmax decreased post-ablation in all patients (125.1 to 111.9 ml, p < 0.001). LAVmin only decreased in patients with a successful outcome post-ablation (65.6 to 58.8 ml, p < 0.001). As a result, LA EF only showed a marked reduction in patients with AF recurrences (42.7 % to 37.9 %, p < 0.001). Post-ablation LA fibrosis could be visualized in 77 % of patients who underwent delayed enhancement MRI (mean amount 1.4 cm(3)). LA fibrosis showed no correlation with the decrease in LAVmax or LA EF.

CONCLUSIONS

PVAI resulted in a reduction of LAVmax in all patients, indicating an effect of ablation induced fibrosis. LAVmin only decreased in patients with a successful outcome, indicating an effect of reverse atrial remodeling. As a result, LA function post-ablation was preserved in patients with a successful outcome and decreased in patients with AF recurrence.

Electrocardiographic P wave changes after thoracoscopic pulmonary vein isolation for atrial fibrillation

BACKGROUND

Changes in P wave duration (PWD) and P wave area (PWA) have been described following catheter ablation for atrial fibrillation (AF). We hypothesize that video-assisted thoracoscopic pulmonary vein isolation (VATS-PVI) for AF results in decrease of PWD, PWA and P wave dispersion, which may resemble reverse electrical remodeling of the atrium after restoration of sinus rhythm.

METHODS

VATS-PVI consisted of PVI and ganglionic plexus ablation in 29 patients (mean age, 59 ± 7 years; 23 males; 17 paroxysmal AF) and additional left atrial lesions in patients with persistent AF. PWD and PWA were measured in ECG lead II, aVF and V2 of ECGs during sinus rhythm before, directly after, and 6 months postprocedure. P wave dispersion was derived from the 12 lead ECG.

RESULTS

Prior to VATS-PVI, PWD did not correlate with left atrial size and no difference in left atrial size was found between patients with paroxysmal or persistent AF (p = 0.27). Following VATS-PVI, PWD initially prolonged in all patients from 115 ± 4.6 ms to 131 ± 3.6 ms (p < 0.01) but shortened to 99 ± 3.2 ms after 6 months (p < 0.01). PWA was 5.60 ± 0.32 mV*ms at baseline, 6.44 ± 0.32 mV*ms post-VATS-PVI (P = NS), and 5.40 ± 0.28 mV*ms after 6 months (p = NS vs. baseline, p < 0.05 vs. post-VATS-PVI). P wave dispersion decreased in the persistent AF group from baseline 67 ± 3.3 to 64 ± 2.5 ms post-VATS-PVI (p = 0.30) and to 61 ± 3.4 ms after 6 months (p < 0.05).

CONCLUSIONS

PWD increases significantly directly after successful VATS-PVI in both groups. There was significant decrease in PWD after 6 months. Similarly, P wave dispersion decreased in the persistent group. These changes suggest an immediate procedure related effect, but the later changes may represent reverse electrical atrial remodeling following cessation of AF.

The use of cardiac magnetic resonance imaging in the diagnostic workup and treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and imposes a huge clinical and economic burden. AF is correlated with an increased morbidity and mortality, mainly due to stroke and heart failure. Cardiovascular imaging modalities, including echocardiography, computed tomography (CT), and cardiovascular magnetic resonance (CMR), play a central role in the workup and treatment of AF. One of the major advantages of CMR is the high contrast to noise ratio combined with good spatial and temporal resolution, without any radiation burden. This allows a detailed assessment of the structure and function of the left atrium (LA). Of particular interest is the ability to visualize the extent of LA wall injury. We provide a focused review of the value of CMR in identifying the underlying pathophysiological mechanisms of AF, its role in stroke prevention and in the guidance of radiofrequency catheter ablation. CMR is a promising technique that could add valuable information for therapeutic decision making in specific subpopulations with AF.

Right atrial anatomical remodeling affects early outcomes of nonvalvular atrial fibrillation after radiofrequency ablation

BACKGROUND

The impact of the right atrial (RA) anatomical remodeling on outcomes of atrial fibrillation (AF) after radiofrequency ablation (RFA) is unclear.

METHODS AND RESULTS

Sixty-three patients (50 men, 57±10 years, 23 persistent AF [PeAF]) who underwent RFA for AF were enrolled. Both RA and left atrial (LA) volumes, measured with multidetector computed tomography, as well as echocardiographic parameters were compared between subjects with early (<3 months, n=13) or 1-year (n=19) recurrence after RFA and without recurrence. The RA volume index (RAVI) was larger (98±21 vs. 77±22 ml/m²) and PeAF was more common (62% vs. 30%) in the early recurrence group (P<0.05 for all), whereas the LA volume index (LAVI) was similar between the 2 groups (78±15 vs. 72±19 ml/m², P=0.23). Notably, RAVI was the only independent predictor of early recurrence (for each 10 ml/m² increase, OR: 1.650, 95%CI: 1.017-2.677, P=0.04). PeAF was the only independent predictor of 1-year recurrence after RFA (OR: 4.496, 95%CI: 1.110-18.211, P=0.04), whereas RAVI and LAVI were not.

CONCLUSIONS

RA anatomical remodeling might affect the early recurrence of AF after RFA. However, the chronicity of AF, rather than RA and LA anatomical remodeling, is a determinant of 1-year recurrence of AF after RFA.