Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies.

INTRODUCTION: Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF). METHODS AND RESULTS: Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre- and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/atrial wall thickness and the luminal area were measured at each segment. Twenty-seven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Post-ablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group. CONCLUSIONS: Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser balloon, RF shows markedly more thickening post-ablation with significant regional variations.

Implantation of leadless pacemakers via inferior vena cava filters is feasible and safe: Insights from a multicenter experience.

BACKGROUND: The leadless Micra transcatheter-pacing system (Micra-TPS) is implanted via a femoral approach using a 27-French introducer sheath. The Micra Transcutaneous Pacing Study excluded patients with inferior vena cava (IVC) filters. OBJECTIVE: To examine the feasibility and safety of Micra-TPS implantation through an IVC filter. METHODS: This multicenter retrospective study included patients with an IVC filter who underwent a Micra-TPS implantation. Data for clinical and IVC filter characteristics, preprocedure imaging, and procedural interventions were collected. The primary outcome was a successful leadless pacemaker (LP) implantation via a femoral approach in the presence of an IVC filter. Periprocedural and delayed clinical complications were also evaluated. RESULTS: Of the 1528 Micra-TPS implants attempted, 23 patients (1.5%) had IVC filters. The majority (69.6%) of IVC filters were permanent. Six (26.1%) patients underwent preprocedural imaging to assess for filter patency. One patient's filter was retrieved before LP implantation. The primary outcome was achieved in 21 of 22 patients (95.5%) with an existing IVC filter. An occluded IVC precluded LP implantation in one patient. Difficulty advancing the stiff guidewire or the 27-Fr sheath was encountered in five patients. These cases required repositioning of the wire (n = 2), gradual sheath upsizing (n = 2), or balloon dilation of the filter (n = 1). Postprocedure fluoroscopy revealed intact filters in all cases. During a median 6-month follow-up, there were no clinical complications related to the filter or the Micra-TPS. CONCLUSION: This multicenter experience demonstrates the feasibility and safety of Micra-TPS implantation via an IVC filter without acute procedural or delayed clinical complications.

Reduced anti-inflammatory gut microbiota are associated with depression and anhedonia.

INTRODUCTION: Characterise gut microbiota distributions of participants with co-occurring depression and anxiety, in those with only depression or with anxiety, and determine if gut bacteria differentially correlates with distinct clinical presentations. METHODS: Participants (10 healthy controls [mean age: 33, 60% female] and 60 psychiatric subjects; major depressive disorder (comorbid with anxiety), n = 38 [mean age: 39.2, 82% female], anxiety only, n = 8 [mean age: 40.0, 100% female], depression only without anxiety, n = 14 [mean age: 41.9, 79% female]) were characterized by psychiatric assessments. Quantitative PCR and 16S rRNA sequencing were used to characterize the gut microbiota in stool samples. RESULTS: Altered microbiota correlated with pre-defined clinical presentation, with Bacteroides (p = 0.011) and the Clostridium leptum subgroup (p = 0.023) significantly different between clinical categories. Cluster analysis of the total sample using weighted UniFrac ß-diversity of the gut microbiota identified two different clusters defined by differences in bacterial distribution. Cluster 2 had higher Bacteroides (p = 0.006), and much reduced presence of Clostridales (p<0.001) compared to Cluster 1. Bifidobacterium (p = 0.0173) was also reduced in Cluster 2 compared to Cluster 1. When evaluated for clinical charateristics, anhedonia scores in Cluster 2 were higher than in Cluster 1. LIMITATIONS: The sample is smaller and predominately female. CONCLUSIONS: Reduced or absent Clostridia was consistently seen in those with depression, independent of the presence of anxiety. Conversely, reduced Bacteroides may be more associated with the presence of anxiety, independent of the presence of depression. These differences suggest that gut microbiota distribution could help clarify the underlying pathology of comorbid clinical presentation.

Meta-analysis of efficacy and safety of apixaban and uninterrupted apixaban therapy compared to vitamin K antagonists in patients undergoing catheter ablation for atrial fibrillation.

BACKGROUND: Apixaban is a Factor Xa inhibitor increasingly being used for stroke prevention in atrial fibrillation (AF). Although several studies have been done, the efficacy and safety of apixaban during the peri-procedural period of AF ablation remains unclear. We sought to systematically review pooled data from these various studies to evaluate thromboembolic and bleeding risks in patients undergoing catheter ablation for AF who are treated with apixaban (interrupted and uninterrupted). METHODS: Studies comparing anticoagulation with apixaban or vitamin K antagonists (VKA) in patients undergoing ablation for AF were identified via an electronic search of MEDLINE, EMBASE, clinical trials.gov, and Cochrane Library from inception to January 2016. Study-specific risk ratios were calculated and combined with a fixed-effects model meta-analysis. RESULTS: In the analysis of 2100 pooled patients, thromboembolic complications (TE) occurred in 14/778 (1.80 %) patients in the apixaban group (AG) compared to 20/1322 patients in the VKA group (RR 1.03, 95 % CI 0.55-1.90, p = 0.93, I 2 = 0 %). Major bleeding occurred in 9/778 (1.2 %) of the AG compared to 20/1322 (1.51 %) in the VKA group (RR 1.03, 95 % CI 0.55-1.90, p = 0.93, I 2 = 0 %). In uninterrupted apixaban group (uAG), TE occurred in 4/585 (0.68 %) patients in the uAG compared to 6/910 (0.66 %) in VKA group (RR 0.86, 95 % CI 0.25-2.95, p = 0.81, I 2 = 0 %). Major bleeding occurred in 5/585 (0.85 %) in uAG compared to 7/910 (0.77 %) in the VKA group (RR 1.20, 95 % CI 0.37-3.88, p = 0.76, I 2 = 0 %). CONCLUSION: Our study demonstrates patients treated with apixaban and VKA during the peri-procedural period for AF ablation have similar rates of TE and bleeding complications. Interrupted and uninterrupted apixaban strategies were associated with similar outcomes.

Major complications and mortality within 30 days of an electrophysiological procedure at an academic medical center: implications for developing national standards.

BACKGROUND: Despite growing attention to performance and quality measures, national standards for reporting of outcomes after all electrophysiology (EP) procedures have not yet been developed. We sought to characterize the incidence and timing of adverse events up to 30 days after EP procedures at a tertiary academic medical center. METHODS AND RESULTS: We prospectively followed all patients undergoing EP procedures between January 2010 and September 2012. All were followed for 30 days postprocedure either in clinic or by telephone. Major complications were defined as events related to the procedure that led to prolongation of hospital stay or readmission, required additional procedural intervention, or resulted in death or significant injury. These were further categorized as intraprocedure, postprocedure, or postdischarge events. Seven EP physicians collectively adjudicated whether complications were directly related to the procedure. A total of 3,213 procedures were performed. Major complications occurred in 2.2% of patients; 49% of these events occurred after discharge. Death occurred in 0.6% of patients; 73% of these deaths were found to be secondary to worsening of the patient's underlying comorbid conditions and unrelated to the procedure. CONCLUSIONS: When considering national standards for reporting outcomes of all EP procedures, continued follow-up after discharge is important. In our cohort, half of major complications occurring within 30 days occurred after discharge. In addition, three-quarters of deaths within 30 days were not directly related to the procedure and caution should be used in using all-cause mortality as an outcome measure for EP procedures.

Left atrial appendage devices for stroke prevention in atrial fibrillation.

Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia, and stroke prevention remains an integral part of management of AF. Long-term therapy with oral anticoagulants, though effective, has many limitations, and these limitations have encouraged the search for device-based alternatives. In patients with non-valvular AF, approximately 90% of thrombi are thought to arise from the left atrial appendage (LAA). The LAA can be obliterated surgically or percutaneously, and this should reduce the incidence of systemic thromboembolic events in AF, ideally without the need for further anticoagulation. We explore the currently available LAA occlusion devices and the evidence behind these devices. Although additional evidence from randomized trials is required to fully characterize the safety and efficacy of all of these devices, LAA occlusion has the potential to offer an attractive alternative for those at high stroke risk but are under-protected because of contraindications to anticoagulant therapy.

Role of the CHADS2 score in the evaluation of thromboembolic risk in patients with atrial fibrillation undergoing transesophageal echocardiography before pulmonary vein isolation.

OBJECTIVES: The goals of this study were to determine: 1) if low-risk patients assessed by a CHADS(2) score, a clinical scoring system quantifying a risk of stroke in patients with atrial fibrillation (AF), require a routine screening transesophageal echocardiogram (TEE) before pulmonary vein isolation (PVI); and 2) the relationship of a CHADS(2) score with left atrial (LA)/left atrial appendage (LAA) spontaneous echo contrast, sludge, and thrombus. BACKGROUND: There is no clear consensus of whether a screening TEE before catheter ablation of AF should be performed in every patient. METHODS: Initial TEEs for pre-PVI of 1,058 AF patients (age 57 +/- 11 years, 80% men) were reviewed and compared with a CHADS(2) score. RESULTS: CHADS(2) scores of 0, 1, 2, 3, 4, 5, and 6 were present in 47%, 33%, 14%, 5%, 1%, 0.3%, and 0% of patients, respectively. The prevalence of LA/LAA thrombus, sludge, and spontaneous echo contrast were present in 0.6%, 1.5%, and 35%. The prevalence of LA/LAA thrombus/sludge increased with ascending CHADS(2) score (scores 0 [0%], 1 [2%], 2 [5%], 3 [9%], and 4 to 6 [11%], p < 0.01). No patient with a CHADS(2) score of 0 had LA/LAA sludge/thrombus. In a multivariate model, history of congestive heart failure and left ventricular ejection fraction <35% were significantly associated with sludge/thrombus. CONCLUSIONS: The prevalence of LA/LAA sludge/thrombus in patients with AF undergoing a pre-PVI screening TEE is very low (<2%) and increases significantly with higher CHADS(2) scores. This suggests that a screening TEE before PVI should be performed in patients with a CHADS(2) score of >or=1, and in patients with a CHADS(2) score of 0 when the AF is persistent and therapeutic anticoagulation has not been maintained for 4 weeks before the procedure.