Initial experience of three-minute freeze cycles using the second-generation cryoballoon ablation: acute and short-term procedural outcomes

Background

The second-generation cryoballoon (CB-A) (Arctic Front Advance, Cryocath, Medtronic, MN, USA) might significantly improve procedural outcome with respect to the first-generation balloon. These technological improvements might also question the current recommendation of the need a 4-min freeze to achieve durable pulmonary vein isolation (PVI).

Objective

The main aim of the study was to analyze the procedural efficacy of a 3-min freeze–thaw cycles with the CB-A balloon in the terms of rates of acute PVI and 6-month outcome.

Methods

Patients having undergone CB-A for PAF or early persistent AF, with 3-min freeze–thaw cycles were consecutively included in our analysis. Acute procedural success was measured in terms of the rate of PVI. Short-term follow-up was evaluated by the means of 24-h Holters and clinical examinations at regular intervals.

Results

Fifty-two consecutive patients (35 male (67 %); mean age, 59.8?±?10.5) were included. Mean procedure and fluoroscopy times were 96?±?15 and 13.2?±?8.3 min, respectively. Mean time from groin puncture to catheter extraction was 60.4?±?20 min. After a mean of 1.5 freeze cycles per vein of 3 min in duration, all 208 (100 %) PVs could be isolated with the CB-A. A total 192 (91 %) veins were isolated during the first freeze. At a mean of 5.7-month follow-up, 82 % of patients were free of AF.

Conclusion

CB-A is effective in producing PVI by using 3-min-duration freeze cycles. After a mean of 1.5 freeze per vein, freedom from AF was achieved in 82 % of patients at 6-month follow-up.     

Angiotensin receptor blockade increases pancreatic insulin secretion and decreases glucose intolerance during glucose supplementation in a model of metabolic syndrome

Renin-angiotensin system blockade improves glucose intolerance and insulin resistance, which contribute to the development of metabolic syndrome. However, the contribution of impaired insulin secretion to the pathogenesis of metabolic syndrome is not well defined. To assess the contributions of angiotensin receptor type 1 (AT?) activation and high glucose intake on pancreatic function and their effects on insulin signaling in skeletal muscle and adipose tissue, an oral glucose tolerance test (oGTT) was performed in five groups (n = 10/group) of rats: 1) lean strain-control 2) obese Otsuka Long-Evans Tokushima Fatty (OLETF), 3) OLETF + angiotensin receptor blocker (ARB; 10 mg/kg · d olmesartan for 6 wk; OLETF ARB), 4) OLETF + 5% glucose water (HG) for 6 wk (OLETF HG), and 5) OLETF + HG + ARB (OLETF HG/ARB). The glucose response to the oGTT increased 58% in OLETF compared with lean-strain control, whereas glucose supplementation increased it an additional 26%. Blockade of angiotensin receptor reduced the oGTT response 19% in the ARB-treated groups and increased pancreatic insulin secretion 64 and 113% in OLETF ARB and OLETF HG/ARB, respectively. ARB treatment in OLETF ARB and OLETF HG/ARB did not have an effect on insulin signaling proteins in skeletal muscle; however, it reduced pancreatic AT? protein expression 20 and 27%, increased pancreatic glucagon-like peptide-1 (GLP-1) receptor protein expression 41 and 88%, respectively, and increased fasting plasma GLP-1 approximately 2.5-fold in OLETF ARB. The results suggest that improvement of glucose intolerance is independent of an improvement in muscle insulin signaling, but rather by improved glucose-stimulated insulin secretion associated with decreased pancreatic AT? activation and increased GLP-1 signaling.     

Comparison of spatial and contrast resolution for cone-beam computed tomography scanners

OBJECTIVE: The purpose was to evaluate the perceived spatial and contrast resolution for a wide range of cone-beam computed tomography (CBCT) devices. STUDY DESIGN: A customized polymethyl methacrylate (PMMA) phantom was developed. Inserts containing a line-pair and rod pattern were used. The phantom was scanned with 13 CBCT devices and 1 multislice CT (MSCT) device using a variety of scanning protocols. The images were presented to 4 observers for scoring. RESULTS: The observer scores showed excellent agreement. A wide range was seen in image quality between CBCT exposure protocols. Compared with the average CBCT scores, the MSCT protocols scored lower for the line-pair insert but higher for the rod insert. CONCLUSIONS: CBCT devices are generally suitable for the visualization of high-contrast structures. Certain exposure protocols can be used for depicting low-contrast structures or fine details. The user should be able to select appropriate exposure protocols according to varying diagnostic requirements.     

Genetic factors associated with the presence and progression of nonalcoholic fatty liver disease: a narrative review

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. Whereas insulin resistance and obesity are considered major risk factors for the development and progression of NAFLD, the genetic underpinnings are unclear. Before 2008, candidate gene studies based on prior knowledge of pathophysiology of fatty liver yielded conflicting results. In 2008, Romeo et al. published the first genome wide association study and reported the strongest genetic signal for the presence of fatty liver (PNPLA3, patatin-like phospholipase domain containing 3; rs738409). Since then, two additional genome wide scans were published and identified 9 additional genetic variants. Whereas these results shed light into the understanding of the genetics of NAFLD, most of associations have not been replicated in independent samples and, therefore, remain undetermined the significance of these findings. This review aims to summarize the understanding of genetic epidemiology of NAFLD and highlights the gaps in knowledge.     

Their pain is not our pain: Brain and autonomic correlates of empathic resonance with the pain of same and different race individuals

Recent advances in social neuroscience research have unveiled the neurophysiological correlates of race and intergroup processing. However, little is known about the neural mechanisms underlying intergroup empathy. Combining event‐related fMRI with measurements of pupil dilation as an index of autonomic reactivity, we explored how race and group membership affect empathy‐related responses. White and Black subjects were presented with video clips depicting white, black, and unfamiliar violet‐skinned hands being either painfully penetrated by a syringe or being touched by a Q‐tip. Both hemodynamic activity within areas known to be involved in the processing of first and third‐person emotional experiences of pain, i.e., bilateral anterior insula, and autonomic reactivity were greater for the pain experienced by own‐race compared to that of other‐race and violet models. Interestingly, greater implicit racial bias predicted increased activity within the left anterior insula during the observation of own‐race pain relative to other‐race pain. Our findings highlight the close link between group‐based segregation and empathic processing. Moreover, they demonstrate the relative influence of culturally acquired implicit attitudes and perceived similarity/familiarity with the target in shaping emotional responses to others' physical pain. Hum Brain Mapp 34:3168–3181, 2013. © 2012 Wiley Periodicals, Inc.     

Selexipag: an oral, selective prostacyclin receptor agonist for the treatment of pulmonary arterial hypertension

In this phase 2 proof-of-concept study we examined the safety and efficacy of selexipag, an orally available, selective prostacyclin receptor (IP receptor) agonist, as a treatment for pulmonary arterial hypertension (PAH). 43 adult patients with symptomatic PAH (receiving stable endothelin receptor antagonist and/or a phosphodiesterase type-5 inhibitor therapy) were randomised three to one to receive either selexipag or placebo. Dosage was up-titrated in 200-μg increments from 200 μg twice daily on day 1 to the maximum tolerated dose by day 35 (maximum allowed dose of 800 μg twice daily). Change in pulmonary vascular resistance at week 17 expressed as a percentage of the baseline value was the primary efficacy end-point, and was analysed in the per protocol set first and then in the all-treated set to assess robustness of results. A statistically significant 30.3% reduction in geometric mean pulmonary vascular resistance was observed after 17 weeks' treatment with selexipag compared with placebo (95% confidence limits -44.7- -12.2; p=0.0045, Wilcoxon rank sum test). This was supported by a similar result from the all-treated set. Selexipag was well tolerated with a safety profile in line with the expected pharmacological effect. Our results encourage the further investigation of selexipag for the treatment of PAH.     

Flexible contextual modulation of naturalistic texture perception in peripheral vision

Peripheral vision comprises most of our visual field, and is essential in guiding visual behavior. Its characteristic capabilities and limitations, which distinguish it from foveal vision, have been explained by the most influential theory of peripheral vision as the product of representing the visual input using summary statistics. Despite its success, this account may provide a limited understanding of peripheral vision, because it neglects processes of perceptual grouping and segmentation. To test this hypothesis, we studied how contextual modulation, namely the modulation of the perception of a stimulus by its surrounds, interacts with segmentation in human peripheral vision. We used naturalistic textures, which are directly related to summary-statistics representations. We show that segmentation cues affect contextual modulation, and that this is not captured by our implementation of the summary-statistics model. We then characterize the effects of different texture statistics on contextual modulation, providing guidance for extending the model, as well as for probing neural mechanisms of peripheral vision.