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Atrial fibrillation is associated with a risk of stroke, primarily from embolization of clots that form in the left atrial appendage. This structure has been targeted to reduce stroke risk in patients who have contraindications to oral anticoagulation. This article appraises the current literature describing surgical and percutaneous isolation of the left atrial appendage., (Copyright © 2015 Cleveland Clinic.)

Objective: In this study we thought to investigate the incidence of left atrial (LA) and left ventricular (LV) fibrosis associated with long term excessive exercise compared to patients with atrial fibrillation (AF) and no history of structural heart disease. Methods: Master endurance athletes (age 48.0 +/- 7.1, 31% women, exercising excessively at least 10 years for more than 10 hours a week) and age and gender matched patients with AF and preserved LV function with no history of structural heart disease (age 49.8 +/- 9.3, 13% women) were retrospectively included for analysis of LA and LV fibrosis. LA enhancement was measured by LGE-MRI and LV fibrosis was analyzed by T1-mapping using MOLLY sequences. The amount of LV fibrosis was calculated as extra cellular volume (ECV). Results: Compared to the AF patients (R2=0.0019), the athletes showed a strong correlation (R2 = 0.643) between LA and LV Fibrosis (fig. 1). In total, the athletes showed a significantly (p=0.0262) higher amount of LA fibrosis than the AF patients (15.7% +/- 4.3% vs. 11.8% +/- 5.3%) as well as a significantly (p<0.0001) higher amount of LV fibrosis (0.029 +/- 0.03 vs. 0.024 +/- 0.035). Conclusion: From our preliminary data atrial fibrillation seems to be associated with cardiac myopathy localized within the atrial chamber, whereas excessive exercise seems to lead to a more global cardiac fibrosis involving both - the atria and ventricles. [ABSTRACT FROM AUTHOR]

Introduction: Left atrial (LA) fibrosis is thought to be a substrate for Atrial Fibrillation (AF) and its ablation emerges as a complementary method for AF management. However, LA fibrosis often continues to increase after ablation and likely affects maintenance of sinus rhythm. Hypothesis: We examined how regression and progression of LA fibrosis affected AF recurrent. Methods: LA enhancement was quantified with Late Gadolinium Enhancement MRI (LGE-MRI) for 127 consecutive AF patients who underwent first time AF ablation. Quantification was done before ablation, 3 months post-ablation and then at least 12 months later. Regressed Fibrosis (RF) was defined as enhancement seen on the first (3-months) post-ablation scan but not on the 1-year post-ablation scan and New Fibrosis (NF) as the enhancement detected only on the 1-year post ablation scan. Results: NF and RF showed no correlation with pre-ablation LA fibrosis. An increase of 1% NF increased the chance of AF recurrence by 3%. (HR 1.03, CI 95% 1 - 1.06, p = 0.05). RF alone showed no impact on future AF recurrence. Hazard ratio for AF recurrence increased when NF become greater (Figure 1-A). Additionally, patients with greater volume of NF (>21%, obtained from ROC analysis) experience significantly more recurrence post-ablation (AF freedom 37% vs 61%, p = 0.01, adjusted for cardiovascular risk factors) than those with less than 21% NF (Figure 1-B). Conclusions: Atrial fibrosis formation is an ongoing process and continues to evolve even after targeted ablation. This data suggests that new fibrosis formation after AF ablation (regardless of pre-ablation enhancement) is a novel marker of long-term procedural outcome and is an independent predictor of AF recurrence. It remains unclear whether contemporary AF management aimed at containing fibrotic structures, can help prolong the arrhythmia free period. [ABSTRACT FROM AUTHOR]

Introduction: Left atrial (LA) volume and function are related to success of atrial fibrillation (AF) ablation. However, the relationship between LA structure and function is not well understood. Magnetic resonance imaging (MRI) is a non-invasive method to assess LA fibrosis and LA function. Hypothesis: Our goal is to evaluate the left atrial functional recovery after successful atrial fibrillation ablation procedure focusing on the ablation lesion sets. Methods: CMR scans were performed in 55 AF patients (66.1±10.5 years) without AF recurrence, at three time points: prior to ablation procedure, in the acute post-ablation period (<48 hours) and at 3 months follow-up. We categorized patients into three groups according to the ablation lesion sets: Gr1{n=11} pulmonary vein isolation only (PVI); Gr2{n=33} PVI, roof line (RL) and posterior wall homogenisation (PH), Gr3{n=11} PVI, RL, PH and additional anterior wall fibrosis homogenization (AH). Maximum (maxLAV), minimum (minLAV) and pre-atrial contraction LA volumes (pre-aLAV) were measured according to the biplane area-length method with CMR. Total, passive and active LA ejection fractions (LAEF) were calculated, and LA fibrosis was quantified using late-gadolinium enhancement images. Results: Comparing the three groups, baseline pre-ablation atrial volumes and function were not significantly different among groups, but Gr3 had higher pre-ablation LA fibrosis% (Gr1 vs Gr2 vs Gr3 11.5±5.1% vs 11.7±4.1% vs 14.8±5.9% p<0.05). In the acute phase, the lowest total LA-EF was identified in Gr3 (Gr1 vs Gr3 total LAEF: 56.9±16.0% vs 37.2±14.9 p<0.05), but during follow-up no significant difference was identified. After 3 months Gr2 showed functional recovery, and total and also active LAEF was significantly higher compared to the baseline function (Gr3 pre-ablation vs follow-up LAEF: 42.5±12.5 vs 51.1±16.5% p<0.005) (Figure). Conclusions: In patient with posterior wall ablation LA function recovered, and additional left atrial fibrosis homogenization did not decrease LA function significantly at follow-up. [ABSTRACT FROM AUTHOR]