Background-The measurement of late gadolinium enhanced MRI (LGE-MRI) intensity in arbitrary units (au), limits the objectivity of thresholds for focal scar detection and inter-patient comparisons of scar burden.

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Objectives We sought to a) use a novel method of late gadolinium enhancement (LGE) quantification that utilizes normalized intensity measures to confirm the association between LGE extent and atrial fibrillation (AF) recurrence following ablation, and b) examine the presence of interaction and effect modification between LGE and AF persistence. Background Recurrent AF after catheter ablation has been reported to associate with the baseline extent of left atrial (LA) LGE on cardiac magnetic resonance (CMR). Traditional methods for measurement of intensity lack an objective threshold for quantification and interpatient comparisons of LGE. Methods The cohort included 165 participants (60.0±10.2 years, 77% men, 57% persistent AF) that underwent initial AF ablation. The association of baseline LGE extent with AF recurrence was examined using multivariable Cox proportional hazard models. Multiplicative and additive interaction between AF type and LGE extent were examined. Results During 10.2±5.7 months of follow-up, 63 (38.2%) patients experienced AF recurrence. Baseline LGE extent was independently associated with AF recurrence after adjusting for confounders [hazard ratio (HR) 1.5 per 10% increased LGE, P<0.001]. The HR for AF recurrence progressively increased as a function of LGE. The magnitude of association between LGE >35% and AF recurrence was greater among patients with persistent AF (HR 6.5, P=0.001 versus HR 3.6, P=0.001); however, there was no evidence for statistical interaction. Conclusions Regardless of AF persistence at baseline, participants with LGE ≤ 35% have a favorable outcome, whereas those with LGE > 35% have a higher rate of AF recurrence in the first year after ablation. These findings suggest a role for a) patient selection for AF ablation using LGE extent, and b) substrate modification in addition to pulmonary vein isolation in patients with LGE extent exceeding 35% of LA myocardium.

Catheter ablation is an important treatment modality for patients with atrial fibrillation (AF). Although the superiority of catheter ablation over antiarrhythmic drug therapy has been demonstrated in middle-aged patients with paroxysmal AF, the role the procedure in other patient subgroups-particularly those with long-standing persistent AF-has not been well defined. Furthermore, although AF ablation can be performed with reasonable efficacy and safety by experienced operators, long-term success rates for single procedures are suboptimal. Fortunately, extensive ongoing research will improve our understanding of the mechanisms of AF, and considerable funds are being invested in developing new ablation technologies to improve patient outcomes. These technologies include ablation catheters designed to electrically isolate the pulmonary veins with improved safety, efficacy, and speed, catheters designed to deliver radiofrequency energy with improved precision, robotic systems to address the technological demands of the procedure, improved imaging and electrical mapping systems, and MRI-guided ablation strategies. The tools, technologies, and techniques that will ultimately stand the test of time and become the standard approach to AF ablation in the future remain unclear. However, technological advances are sure to result in the necessary improvements in the safety and efficacy of AF ablation procedures.

Catheter ablation of atrial fibrillation (AF) has become an important treatment method. Electrical isolation of the pulmonary veins is the cornerstone of most AF ablation procedures, and is defined by an entrance block observed on a circular multipolar electrode catheter. The safety and efficacy of AF ablation is best established in middle-aged patients with paroxysmal AF. Current guidelines recommend AF ablation with a level Ia indication in this group of patients. The long-term efficacy of AF ablation is well established in patients with paroxysmal AF, but less so in patients with longstanding persistent AF. In this population, current guidelines recommend AF ablation with a level IIb indication. The efficacy of catheter ablation in other patient populations, particularly elderly people and those with concomitant conditions, is also poorly defined. AF ablation is reasonably effective and safe at 12 months of follow-up, but recurrence of AF ≥1 year after ablation is not uncommon. Fortunately, the techniques and tools used for AF ablation continue to evolve. These developments include novel ablation catheters designed to increase safety, efficacy, and precision of the procedure, ablation strategies to target both pulmonary vein and nonpulmonary vein AF triggers, and improved imaging and electrical mapping to guide ablation procedures.

Background Catheter ablation utilizing radiofrequency (RF), Cryothermal (Cryo), or Laser energy is effective for treatment of atrial fibrillation (AF). Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) has been used to estimate the burden of LA fibrosis, but no data exists regarding structural changes following each modality. We sought to compare the baseline to post-procedure change in left atrial (LA) scar burden following RF, Cryo, or Laser ablation for treatment of AF. Methods Seventeen patients with AF underwent initial pulmonary vein isolation (PVI) using RF (n=7), Cryo (n=5), and Laser (n=5). LGE-MRI was performed prior to, at 24 hours and 3 months after PVI. Results In a linear mixed-effects model, accounting for intra-patient clustering of data and inter-patient differences in baseline scar, LGE extent was significantly increased at 24 hours post ablation (+14.6±1.9% of LA myocardium, P<0.001), and remained stable from 24 hours to 3 months (+0.12±1.9%, P=0.951). There was no statistically significant difference between the post ablation scar extent among ablation modalities when compared to RF (Cryo +4.5 ± 3.0%, P=0.123; Laser −3.2 ± 3.0%, P=0.291). The PV antral LGE intensity was increased by 25.1±3.8% (P<0.001) 24 hours after ablation and additionally increased by 8.1±3.8 at 3 months (P=0.033). Conclusions Radiofrequency, Cryo, and laser ablation result in increased LGE extent and intensity at 24 hours and 3 months post ablation. No statistically sugnificant difference was noted in the extent of fibrosis induced by any modality.

Background The impact of well-controlled or historical psychiatric diagnoses in patients seeking bariatric surgery (BS) on perioperative outcomes is unclear. The primary objective of this study was to determine the impact of psychiatric diagnoses on hospital length of stay (LOS), 30-day readmission rates after BS, and post-operative weight loss outcomes. Methods Patients who underwent laparoscopic sleeve gastrectomy (LSG) or Roux-en-Y gastric bypass (LRNYGB) from 2014 to 2016 at a single academic institution were retrospectively reviewed. Baseline demographic data and psychiatric history including depression, anxiety, and/or bipolar disorder (DAB) were obtained from the electronic medical record. Hospital LOS, 30-day readmissions, and % excess body weight loss (%EBWL) were obtained on all patients and compared between DAB patients and those without any psychiatric history. Results During the study period, 354 patients were reviewed, of which 78% were female; 60% underwent LSG. The mean preoperative BMI was 48.9 ± 8.4 m/kg2. Major depression was the leading diagnosis (42%), and 13% had both depression and anxiety. The 30-day readmission rate was significantly higher than the control (10.5% vs. 3.7%, p = 0.02). Mean hospital LOS and the incidence of long hospital LOS (≥ 4 days) was not different between the groups, although within LSG patients, the incidence of long hospital LOS trended towards being higher for DAB patients (9.2% vs. 4%, p = 0.10). Patients with depression and anxiety had a higher incidence of long LOS (23.4% vs. 9.2%, p < 0.005). While 6-month %EBWL was significantly lower for DAB patients (41% vs. 46%, p = 0.004), 1-year weight loss outcomes were not different, even when adjusting for surgical procedure. Conclusion Patients with baseline or historical DAB had significantly higher early readmission rates, and those with multiple diagnoses were associated with a hospital LOS ≥ 4 days. Future studies should focus on elucidating the impact of psychiatric diagnoses on these quality metrics.

High output pacing around the right pulmonary veins and the carina reveals that the phrenic nerve lies along a wide-area circumferential ablation trajectory in 30% of patients. Modification of ablation lines to avoid these sites may prevent phrenic nerve injury during RF PVI.