Comparison of voltage map-guided left atrial anterior wall ablation versus left lateral mitral isthmus ablation in patients with persistent atrial fibrillation

doi:10.1016/j.hrthm.2010.10.015

Heart Rhythm

Volume 8, Issue 2, February 2011, Pages 199-206

https://doi.org/10.1016/j.hrthm.2010.10.015 Get rights and content

Background

Left lateral mitral isthmus (LLMI) ablation achieves a low percentage of bidirectional conduction block in atrial fibrillation (AF) ablation.

Objective

The purpose of this study was to investigate whether linear ablation through the lowest voltage area on the left atrial anterior wall (LAAW) can lead to better clinical outcomes compared to LLMI ablation.

Methods

We obtained high-density three-dimensional (3D) voltage mapping (CARTO) of the LA in 29 patients with persistent AF and determined the area of low voltage. In the multicenter prospective study, clinical outcomes of LAAW (n = 100) and LLMI ablations (n = 100) were compared in patients with persistent AF (79.4% male, 59.4 ± 10.6 years).

Results

(1) The low-voltage area consistently existed on LAAW and had a correlation with the LA–aorta contact area (R = 0.921, P <.0001). Mean voltage of LAAW was significantly lower than that of LLMI (P <.0001). (2) The length of LAAW ablation (37.9 ± 3.4 mm vs 26.6 ± 3.2 mm, P <.0001) was longer, but achievement of bidirectional block was higher (68.0% vs 32.0%, P = .0001) than in LLMI ablation. Mean duration of LAAW and LLMI ablations was 19.3 ± 2.9 minutes and 18.2 ± 3.7 minutes, respectively (P = .086). (3) During follow-up of 23.3 ± 7.4 months, the recurrence rate of AF after LAAW ablation (26.0%) was significantly lower than that of LLMI ablation (41.0%, P = .021) after a single procedure.

Conclusion

The voltage map is useful for guiding linear ablation in persistent AF patients. LAAW is the most frequent low-voltage area around the mitral annulus, and linear ablation along LAAW results in a better clinical outcome with a higher rate of bidirectional conduction block compared to LLMI ablation.

Introduction

The efficacy of bi-antral isolation for paroxysmal atrial fibrillation (AF) is well established and considered to be the cornerstone for all forms of radiofrequency (RF) catheter ablation of AF.1, 2, 3, 4 However, bi-antral isolation alone has not been shown to be effective in persistent AF and is associated with higher recurrence rates. The primary reason for less successful outcomes might be due to longer duration of AF associated with more extensive substrate remodeling and atrial dilatation in persistent AF.5, 6, 7, 8 Persistent AF often accompanies organized atrial reentrant tachycardia or flutter after bi-antral isolation during RF catheter ablation, and a significant number of them have perimitral circuits. Linear ablation created over the left atrial (LA) roof and the left lateral mitral valve isthmus (LLMI) has been shown to be effective in eliminating the tachycardia when complete bidirectional conduction block was achieved.9, 10, 11 However, achieving complete bidirectional conduction block of LLMI is difficult in a significant number of patients,¹² possibly because of the wide range of anatomic variations¹³ and because the procedure often requires epicardial ablation from the coronary sinus¹⁴ or pericardial space¹⁵ that can be associated with significant complications.⁹ Therefore, we hypothesized that an LA voltage map may guide linear ablation of AF (including perimitral reentry), and linear ablation through the low-voltage area surrounding the mitral valve area might be easier for achieving bidirectional block, resulting in better clinical outcomes compared to LLMI ablation.

Section snippets

Study population

The study protocol was approved by the institutional review boards, and proper informed consent was obtained. The study included patients with persistent AF who were refractory to more than two antiarrhythmic drugs and referred for catheter ablation. Exclusion criteria were as follows: (1) permanent AF refractory to electrical cardioversion; (2) age ≤18 years or >80 years; (3) LA size >55 mm measured on echocardiogram; (4) aortic aneurysm or dissection; (5) AF with rheumatic valvular disease;

High-density 3D voltage mapping study

The initial 29 patients underwent high-density 3D voltage mapping and analysis for LA–aorta contact area by cardiac MRI. Cardiac MRI showed that all 29 patients had enlarged LA volume (140.3 ± 20.9 mL). In most patients, the lowest-voltage area (0.63 ± 0.21 mV) was located on LAAW (n = 20; Figure 1). Other locations included the anteroseptum (n = 5), diffuse (n = 3), and posterior wall (n = 1). The endocardial voltage of LAAW (0.81 ± 0.31 mV) was significantly lower than that of LLMI (3.18 ±

Discussion

In this study, we attempted to rationalize the linear ablation strategy based on endocardial voltage around the mitral annulus in patients with persistent AF. We first demonstrated that LAAW has a consistently low-voltage area at the LA–aorta contiguous area around the mitral annulus (11–12 o'clock direction). Linear ablation across the low-voltage area on the LAAW was easier for achieving bidirectional conduction block of perimitral reentry. In prospective nonrandomized comparison, linear

Conclusion

A voltage map is useful for guiding linear ablation in patients with persistent AF. LAAW is the most frequent low-voltage area around the mitral annulus at the LA–aorta contiguous region and is more susceptible to conduction block than LLMI with high voltage. Linear ablation along the LAAW results in a better clinical outcome with a higher rate of bidirectional conduction block compared to LLMI ablation.

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Anterior mitral line in patients with persistent atrial fibrillation and anterior scar: A multicenter matched comparison—The MiLine study
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The benefit of an anterior mitral line (AML) in patients with persistent atrial fibrillation (AF) and anterior atrial scar undergoing ablation has never been investigated.
The purpose of this study was to evaluate the outcomes of AML in addition to standard treatment compared to standard treatment alone (no AML) in this subset of patients.
Patients with persistent AF and anterior low-voltage zone (LVZ) treated with AML in 3 centers were retrospectively enrolled. The patients were matched in 1:1 fashion with patients having persistent AF and anterior LVZ who underwent conventional ablation in the same centers. Matching parameters were age, LVZ burden, and repeated ablation. Primary endpoint was AF/atrial tachycardia (AT) recurrence.
One hundred eight-six patients (age 66 ± 9 years; 34% women) were selected and divided into 2 matched groups. Bidirectional conduction block was achieved in 95% of AML. After median follow-up of 2 years, AF/AT recurrence occurred in 29% of the patients in the AML group vs 48% in the no AML group (log-rank P = .024). On Cox regression multivariate analysis, left atrial volume (hazard ratio [HR] 1.03; P = .006) and AML (HR 0.46; P = .003) were significantly associated with the primary endpoint. On univariate logistic regression, lower body mass index, older age, extensive anterior LVZ, and position of the left atrial activation breakthrough away from the AML were associated with first-pass AML block.
In this retrospective matched analysis of patients with persistent AF and anterior scar, AML in addition to standard treatment was associated with improved AF/AT-free survival compared to standard treatment alone.
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Left atrial linear lesions are one of the main techniques described in the ablation of persistent AF and left AT. However, obtaining bidirectional block following linear ablation of the MI remains challenging, with reported success rates from 32% to 92%.6–8 Furthermore, incomplete lines of block are proarrhythmic and linked with an increased risk of AT recurrence to up to 4 times,9 mainly presenting as PMF rather than AF.10
The Electrical Isolation of the Left Atrial Posterior Wall in Catheter Ablation of Persistent Atrial Fibrillation
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In the presence of significant atrial remodeling, extra-PV triggers are known to play an important role in the AF induction and maintenance (5), and an empirical extra-PV LA ablation, such as a linear ablation or complex fractionated atrial electrogram (CFAE)-guided ablation, has been performed in patients with persistent AF (6,7). Haissaguerre et al. (19) proposed a rational linear ablation protocol called the stepwise approach, and its clinical utility for an empirical linear ablation has been demonstrated in several non-randomized clinical studies (8–10). However, Verma et al. (11) reversed this dogma by showing that an empirical extra-PV ablation has no additional benefit over the CPVI in a multicenter prospective randomized trial.
This study explored whether complete electrical isolation of the left atrial (LA) posterior wall improves the rhythm outcome of catheter ablation of persistent atrial fibrillation (AF).
Although the STAR AF2 (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial Part II) proved no additional benefit of empirical extra-pulmonary vein (PV) LA ablation, the long-term recurrence rate after circumferential PV isolation (CPVI) alone remains high.
We randomly assigned 217 patients with persistent AF (83.1% men, age 58.7 ± 10.8 years, 73.3% long-standing persistent AF) to ablation with CPVI alone (CPVI group) or CPVI with a POsterior wall Box Isolation (POBI group). The endpoint of the POBI group was the elimination of the posterior atrial potentials by roof and posterior inferior lines and touch-up focal ablation.
After a mean follow-up of 16.2 ± 8.8 months, the clinical recurrence rate did not significantly differ between the 2 groups (23.8% vs. 26.5%; p = 0.779) in the CPVI and POBI groups. The recurrence rate for atrial tachycardias (16.0% vs. 11.1%; p = 0.913) and cardioversion rates (6.7% vs. 13.7%; p = 0.093) to control clinical recurrences also did not significantly differ between the 2 groups. At the final follow-up, sinus rhythm was maintained without antiarrhythmic drug in 50.5% and 55.9% in the CPVI and POBI groups, respectively (p = 0.522). No significant difference was found in the major complication rates between the 2 groups, but the total ablation time was significantly longer in the POBI group (4,289 ± 1,837 s vs. 5,365 ± 2,358 s; p < 0.001).
In patients with persistent AF, an empirical complete POBI did not improve the rhythm outcome of catheter ablation or influence the type of recurrent atrial arrhythmia. (Comparison of Circumferential Pulmonary Vein Isolation Alone Versus Linear Ablation in Addition to Circumferential Pulmonary Vein Isolation for Catheter Ablation in Persistent Atrial Fibrillation: Prospective Randomized Controlled Trial; NCT02721121).
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This study sought to compare efficacy and safety of the septal mitral isthmus line (SMIL) with that of the lateral mitral isthmus line (LMIL) for treatment of mitral annular flutter (MAF).
MAF is the most common left atrial macro-re-entrant organized atrial tachycardia (OAT) occurring after catheter ablation of atrial fibrillation. The 2 most common lesion sets for treating MAF include linear ablation from the anteroseptal mitral annulus to the right superior pulmonary vein (SMIL) and from the lateral mitral annulus to left inferior pulmonary vein (LMIL).
The study included all mitral isthmus ablations performed at the Hospital of the University of Pennsylvania in 2016 and 2017. Acute procedural results and long-term arrhythmia-free survival were compared between groups.
Of 114 total MILs, conduction block was achieved across 73 (93.6%) SMILs compared with 29 (80.6%) LMILs (p = 0.05). Although the length of the SMIL was longer (48.9 ± 12.8 cm vs. 38.7 ± 12.8 cm; p = 0.001), time required to achieve block was shorter (25.2 ± 15.9 min vs. 36.6 ± 21.3 min; p = 0.03). Coronary sinus ablation was required in 58.3% of LMILs due to inability to achieve conduction block with left atrial ablation alone. In multivariate analysis, only failure to achieve acute MIL block remained significantly associated with subsequent OAT recurrence (hazard ratio: 6.39; 95% confidence interval: 1.37 to 29.9; p = 0.02).
The SMIL requires less time to complete and more frequently results in acute MIL block than the LMIL. Additionally, ablation is rarely required outside the left atrium. Failure to achieve acute MIL block is strongly associated with subsequent OAT recurrence.
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: The first two authors contributed equally to this study. This work was supported by a grant (7-2010-0287) from the Korea Health 21 R&D Project, Ministry of Health and Welfare and a grant (2010-0010537) from the Basic Science Research Program run by the National Research Foundation of Korea (NRF) that is funded by the Ministry of Education, Science and Technology of the Republic of Korea. This manuscript was processed by a guest editor.

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ClinicalAblationComparison of voltage map-guided left atrial anterior wall ablation versus left lateral mitral isthmus ablation in patients with persistent atrial fibrillation

Background

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Study population

High-density 3D voltage mapping study

Discussion

Conclusion

Heart Rhythm

J Am Coll Cardiol

J Am Coll Cardiol

Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation

Circulation

Circumferential pulmonary-vein ablation for chronic atrial fibrillation

N Engl J Med

Complete isolation of left atrium surrounding the pulmonary veins: new insights from the double-Lasso technique in paroxysmal atrial fibrillation

Circulation

Electroanatomic characteristics of atrial premature beats triggering atrial fibrillation in patients with persistent versus paroxysmal atrial fibrillation

J Cardiovasc Electrophysiol

Prospective assessment of late conduction recurrence across radiofrequency lesions producing electrical disconnection at the pulmonary vein ostium in patients with atrial fibrillation

Circulation

Mechanisms of organized left atrial tachycardias occurring after pulmonary vein isolation

Circulation

Technique and results of linear ablation at the mitral isthmus

Circulation

Techniques, evaluation, and consequences of linear block at the left atrial roof in paroxysmal atrial fibrillation: a prospective randomized study

Circulation

Left mitral isthmus ablation associated with PV Isolation: long-term results of a prospective randomized study

J Cardiovasc Electrophysiol

Clinical
Ablation
Comparison of voltage map-guided left atrial anterior wall ablation versus left lateral mitral isthmus ablation in patients with persistent atrial fibrillation