Impact of channels identification and ablation in ventricular tachycardia patients through high-density mapping: preliminary experience from an Italian registry

Funding Acknowledgements

Type of funding sources: None.

Background

Ventricular tachycardia (VT) ablation techniques in ischemic cardiomyopathy have evolved during the recent years. However, the long-term success rate remains disappointing. A technique based on channel identification and ablation through a novel automated algorithm may limit the extent of ablation needed and possibly lead to higher successful rate.

Purpose

To report preliminary data on feasibility and safety of a channel identification approach and to characterize late potentials (LPs) features using an ultra-high density mapping system with a novel analysis tool in ischemic VT procedures.

Methods

Consecutive patients (pts) indicated for ischemic VT ablation were enrolled in the CHARISMA study. A complete map of the left ventricle was performed prior and after ablation through the Rhythmia mapping system. For our purpose channels were defined as any signal activity bounded by anatomic and functional barriers and characterized through a novel map analysis tool (Lumipoint-LM-) that automatically identifies fragmented late potentials (LPs) and continuous activation was used on the whole ventricular substrate. Procedural endpoint was the elimination of all identified conducting channels (CCs) by ablation at the CC entrance and exit followed by abolition of any residual LPs inside the CC. The ablation endpoint was noninducibility.

Results

A total of 18 channels were identified through LM from 14 pts: 71.4% of the pts had 1 CC, 28.6% had 2 CCs. In the majority of the cases LPs where identified only inside CCs (57.1%), whereas in 6 cases (42.9%) LPs were present both inside and outside. The mean conduction time inside CCs was 50.3 ± 30ms, the mean CC length was 32.6 ± 17mm and the conduction velocity was 0.8 ± 0.5 mm/ms. LPs covered a mean area of 7.0 ± 5mm2 (ratio between LPs area and CCs’ area = 52.4 ± 33.7%). At voltage map analysis 1 CC was present in 78.6% of the cases (2 CCs in 21.4%). LPs were identified only inside CCs in 42.9% of the cases, both inside and outside in 50% and only outside in 7.1%. Healthy tissue (voltage level≥0.5mV) was prevalent (61.2 ± 13.8%), followed by intermediate voltage areas (0.5-0.05mV; 37.5 ± 13.7%) and very low voltage areas (<0.05mV; 1.2 ± 2%). LPs were found mostly at intermediate voltage areas (54.1 ± 31.7% of the covered area; 39.1 ± 28.4% at healthy tissue and 6.8 ± 17.8% at very low voltage areas). Agreement in CCs identification between advanced analysis through LM and voltage map was fair (9/14 with complete agreement). In 3 cases voltage map overestimated LPs areas, in 2 cases failed to fully identify LPs. All CCs’ entrance and exit were successfully ablated and abolition of any residual LPs inside the CC was achieved in all pts. No complication occurred. Noninducibility was achieved in all the cases.

Conclusions

In our preliminary experience, a new channel identification approach through the advanced Lumipoint algorithm seems to be safe, feasible and effective at least in the acute setting of ischemic VT ablation.

Minimal fluoroscopic approaches and factors associated with radiation dose when high-definition mapping is used for supraventricular tachycardia ablation: insight from the CHARISMA registry

Funding Acknowledgements

Type of funding sources: None.

Background

Limited data exist on factors associated with radiation exposure during ablation procedures when a high definition mapping technology is used.

Purpose

To report factors associated with radiation exposure and data on feasibility and safety of a minimal fluoroscopic approach using the Rhythmia mapping system in supraventricular tachycardia (SVT) ablation procedures.

Methods

Consecutive patients indicated for arrhythmia ablation were enrolled in the CHARISMA study at 12 centers. We included in this analysis consecutive right-side procedures performed through a minimal fluoroscopy approach with the Rhythmia mapping system were analyzed. A 3D geometry of chambers of interest was reconstructed on the basis of the electroanatomic information taken from the mapping system. Fluoroscopy was used only if deemed necessary. The effective dose (ED) was calculated using accepted formula. For our purpose high dose exposure was defined as an ED greater than the median value of ED of the population exposed to radiation.

Results

This analysis included 325 patients (mean age = 56 ± 17 years, 57% male) undergoing SVT procedures (152 AVNRT, 116 AFL, 41 AP and 16 AT). During the study, 27481 seconds of fluoroscopy was used (84.6 ± 224 seconds per procedure), resulting in a mean equivalent ED of 1.1 ± 3.7 mSv per patient. The mean reconstructed RA volume was 99 ± 54 ml in a mean mapping time of 12.2 ± 7 min. The mean number of radiofrequency ablations (RFC) to terminate each arrhythmia was 9.4 ± 9 (mean RFC delivery time equal to 6.7 ± 6 min). 192 procedures (59.1%) were completed without any use of fluoroscopy; during the remaining 133 procedures (39.9%), 206.6 ± 313.4 seconds of fluoroscopy was used (median ED = 1.2 mSv). In a minority of the cases (n = 25, 7.7%) the fluoroscopy time was higher than 5 minutes (median ED = 6.5 mSv), whereas radiologic exposure time greater than 1 minute occurred in ninety cases (27.7%, median ED = 2.1 mSv). On multivariate logistic analysis adjusted for baseline confounders the RFC application time (OR = 1.0014, 95%CI: 1.0007 to 1.0022; p = 0.0001) was independently associated to an ED greater than 1.2 mSv, whereas female gender had an inverse association (0.54, 0.29 to 0.98; p = 0.0435). Acute success was reached in 97.8% of the cases. During a mean of 290.7 ± 169.6 days follow-up, no major adverse events related to the procedure were reported. Overall, the recurrence rate of the primary arrhythmia during follow-up was 2.5%.

Conclusions

In our experience, arrhythmias ablation through minimal fluoroscopy approach with the use of a novel ablation technology is safe, feasible, and effective in common right atrial arrhythmias. High-dose exposure occurred in a very limited number of cases, without any reduction of the safety and acute and long-term effectiveness profile.

A mixture of quebracho and chestnut tannins drives butyrate-producing bacteria populations shift in the gut microbiota of weaned piglets

Weaning is a critical period for piglets, in which unbalanced gut microbiota and/or pathogen colonisation can contribute to diseases that interfere with animal performance. Tannins are natural compounds that could be used as functional ingredients to improve gut health in pig farming thanks to their antibacterial, antioxidant, and antidiarrhoeal properties. In this study, a mixture of quebracho and chestnut tannins (1.25%) was evaluated for its efficacy in reducing the negative weaning effects on piglet growth. Microbiota composition was assessed by Illumina MiSeq 16S rRNA gene sequencing of DNA extracted from stools at the end of the trial. Sequence analysis revealed an increase in the genera Shuttleworthia, Pseudobutyrivibrio, Peptococcus, Anaerostipes, and Solobacterium in the tannin-supplemented group. Conversely, this dietary intervention reduced the abundance of the genera Syntrophococcus, Atopobium, Mitsuokella, Sharpea, and Prevotella. The populations of butyrate-producing bacteria were modulated by tannin, and higher butyrate concentrations in stools were detected in the tannin-fed pigs. Co-occurrence analysis revealed that the operational taxonomic units (OTUs) belonging to the families Veillonellaceae, Lachnospiraceae, and Coriobacteriaceae occupied the central part of the network in both the control and the tannin-fed animals. Instead, in the tannin group, the OTUs belonging to the families Acidaminococcaceae, Alcaligenaceae, and Spirochaetaceae characterised its network, whereas Family XIII Incertae Sedis occupied a more central position than in the control group. Conversely, the presence of Desulfovibrionaceae characterised the network of the control group, and this family was not present in the network of the tannin group. Moreover, the prediction of metabolic pathways revealed that the gut microbiome of the tannin group possessed an enhanced potential for carbohydrate transport and metabolism, as well as a lower abundance of pathways related to cell wall/membrane/envelope biogenesis and inorganic ion transport. In conclusion, the tested tannins seem to modulate the gut microbiota, favouring groups of butyrate-producing bacteria.

The Effect of Different Sources of Selenium Supplementation on the Meat Quality Traits of Young Charolaise Bulls during the Finishing Phase

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of finishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg⁻¹ dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 0.01). SY and OH-SeMet reduced the shear force of the meat (p < 0.0001), improved pH (p < 0.001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.

Implications of Tributyrin on Gut Microbiota Shifts Related to Performances of Weaning Piglets

Alternatives to antibiotic treatments are required owing to the ban on the use of these drugs as growth promoters in food animal production. Tributyrin appears to play a role in improving growth performance in pigs, albeit with varying degrees of effectiveness. So far, very little is known about its effects on gut microbiota composition. In this study, we investigated the gut microbiota changes of piglets receiving, at weaning, 0.2% tributyrin added to their basal diet. Microbiota composition was assessed through 16S-rRNA gene sequencing on stools collected from tributyrin and control groups. The functional profiles of microbial communities were predicted from amplicon abundance data. A comparison between dietary groups revealed that tributyrin strongly modulated gut microbiota composition in piglets, increasing the relative abundance of a number of bacterial genera such as Oscillospira, Oscillibacter, Mucispirillum and Butyrivibrio. These genera were positively correlated to animal average daily gain (ADG) and/or body weight (BW). Based on the function profile prediction, the gut microbiome of the tributyrin group possessed an enhanced potential for energy metabolism and a reduced potential for carbohydrate metabolism. In conclusion, our results indicated that tributyrin can promote changes to gut microbial communities, which could contribute to improving animal performance after weaning.

Preparation, properties, and applications of magnetic hematite microparticles

Hematite microparticles are becoming increasingly important components in the soft matter field. The remarkable combination of magnetic and photocatalytic properties that characterize them, coupled with the variety of uniform and monodisperse shapes that they can be synthesized in, makes them a one of a kind colloidal model system. Thanks to these properties, hematite microparticles have been recently applied in several important soft matter applications, spanning from novel colloidal building blocks for self-assembly to necessary tools to investigate and understand fundamental problems. In this review article we provide a detailed overview of the traditional methods available for the preparation of hematite microparticles of different shapes, devoting special attention on some of the most common hiccups that could hider a successful synthesis. We furthermore review the particles' most important physico-chemical properties and their most relevant applications in the soft matter field.

Bioimpedance to Assess the Body Composition of High-performance Karate Athletes: Applications, Advantages and Perspectives

Karate, a millennial martial art, was recently inserted among traditional Olympic combat sports for the Olympic Games in Japan. The aim of the present study is to determine, through bioimpedance analysis, the body composition of high-performance athletes participating in the São Paulo Olympic Karate Project. Participants were 22 athletes of both sexes, average age of 23.6 (6.0) years old, body mass of 66.6 (13.5) kg and fat percentage of 16.6 (5.5)%. Bioimpedance test indicated significant differences between sexes related to sexual dysmorphia, which had an impact on bioelectrical variables. Through comparative evaluation between male and female athletes, this study contributes to body composition analysis, indicating that, in the future, related bioimpedance tests should be used beyond their classical application, including phase angle, muscle function and other attributes.

Review: Chestnut and quebracho tannins in pig nutrition: the effects on performance and intestinal health

Natural extracts are frequently adopted as a valuable alternative to antibiotics in intensive animal farming. Their diverse bioactive constituents such as phytosterols, glucosinolates, carotenoids and polyphenols have shown antioxidant, anti-inflammatory and antibacterial effects. Tannins are the largest class of polyphenol compounds of plant extracts, which can be classified into two hydrolysable or condensed subgroups. Poultry and swine nutrition are the most important sectors in which tannins have been used, firstly adopting tannin-rich feedstuffs and more recently, using tannin extracts from different plants. Several commercial products are available containing tannins extracted from the European chestnut tree (Castanea sativa Mill.) and the American quebracho (Schinopsis spp.). Tannins extracted from these plants have been applied on intensive swine farms due to their ability to improve animal performance and health. These positive and prominent effects are frequently associated with the antinutritional effects in reducing feed palatability, digestibility and protein utilization of feed. Some criticisms and contrasting results regarding pig performance and intestinal health have been reported. This paper provides an overview of the effects of chestnut and quebracho tannins on growth performance and intestinal health of pigs in order to clarify the appropriate dosage and response in the various physiological stages.

125 Mint oils: in vitro anti-inflammatory effects tested in porcine alveolar macrophages

Essential oils as feed additives are being investigated for promoting health in piglets due to their anti-inflammatory activity. The objective of the study was to measure the in vitro anti-inflammatory effects of peppermint oil and spearmint oil with porcine alveolar macrophages as host immune responses. Briefly, macrophages were harvested from the bronchial lavage of 6 pigs at 6 weeks of age, and then seeded into 24-well plate with at 106 cells/mL. After 24 h incubation at 37oC and 5% CO2, cells were treated with mint oil or lipopolysaccharide (LPS) by randomized complete block design with 12 replicates. The treatments were 2 × 5 factorial arrangement with 2 doses of LPS (0 or 1 μg/mL) and 5 doses of mint oil (0, 25, 50, 100, 200 µg/mL). The supernatants were collected after another 24 h incubation to measure the concentration of tumor necrosis factor alpha (TNF-α) by ELISA assay. Cell viability was also tested by the MTT assay. Data were analyzed using the MIXED procedure of SAS 9.4. Administration of both mint oils and LPS did not impact the PAM cell viability of macrophages. LPS challenge significantly stimulated (P &lt; 0.05) TNF-α secretion from macrophages. In the non-challenge group, peppermint oil reduced (P &lt; 0.05) TNF-α production at 25, 50, and 100 μg/mL, whereas spearmint oil reduced (P &lt; 0.05) TNF-α concentration from 50 to 200 μg/mL. In the LPS challenge group, both mint oils linearly inhibited (P &lt; 0.001) TNF-α secretion from LPS-challenged macrophages with 200 μg/mL as the strongest dose. Results of the current study indicated that both peppermint and spearmint oils had anti-inflammatory activities in vitro. In vivo animal trials will be conducted to evaluate their impacts on animal health and performance.

PSIX-12 Effects of tannin supplementation on zootechnical performance and blood parameters of weaned piglets

Weaned piglets often suffer from the enteric disorders and post-weaning diarrhoea. Natural extracts, due to its functional properties, such as tannins from chestnut and quebracho are often considered as feed additives against diarrhoea after the antibiotics ban (Reg. UE 1831/2003). The aim of this study was to evaluate the dietary effects of tannins on growth performance and blood parameters of weaned piglets. A total of 120 piglets (Large White x Landrace) weaned at d 28±2 were randomly allotted to one of two treatments (control vs. tannin) with 6 pens per treatment and 10 pigs per pen. The tannin diet was supplemented with 1.25% of chestnut and quebracho tannins (Silvateam, Italy). The experiment lasted 40 days. Individual body weight (BW) was recorded at d 0, 14, 28 and 40. Feed intake was measured weekly to calculate feed efficiency from d 0 to 14, d 14 to 28, and d 28 to 40. Blood samples were collected on d 40 from a subset of animals (4 pigs/pen). Data were analyzed using PROC GLIMMIX of SAS 9.4 (SAS Inst. Inc., Cary, NC). Supplementation of tannins did not affect BW and feed intake throughout the experiment. However, addition of tannins showed tendency to increase the feed efficiency on d 14 to d 28, compared with control (P = 0.54; 60.4 vs. 52.3, respectively). Dietary addition of tannins significantly increase the serum concentration of albumin, and decrease of globulin, urea and creatinine compared with control (P &lt; 0.05; 23.05 vs. 19.31 g/L, 30.13 vs. 33.58 g/L; 0.98 vs. 2.18 mmol/L; 53.92 vs. 78.92 μmol/L, respectively). In conclusion, tannin supplementation impacted the blood parameters that were related to protein utilization, although this benefit was not reflected in growth performance of weaned pigs.

Minimal fluoroscopy approach in current clinical practice with a novel ablation technology for supraventricular tachycardia: a large multicenter experience from an Italian registry

Background

Electrophysiological studies and ablation procedures expose both physicians and patients to a large amount of radiation. Most of 3-D mapping systems provide improved tracking of catheters, possibly allowing relevant reductions in radiation exposure. No data exists on the ability of the Rhythmia mapping system to minimize fluoroscopy time and dose.

Purpose

To report preliminary data on feasibility and safety of a minimal fluoroscopic approach using the Rhythmia mapping system in supraventricular tachycardia (SVT) procedures.

Methods

Consecutive patients indicated for arrhythmia ablation were enrolled in the CHARISMA study at 12 centers. For our purpose consecutive right-side procedures performed through a minimal fluoroscopy approach with the Rhythmia mapping system were analyzed. A 3D geometry of chambers of interest was reconstructed on the basis of the electroanatomic information taken from the mapping system. Fluoroscopy was used only if deemed necessary.

Results

This analysis included 266 patients (mean age = 57±17 years, 57% male) undergoing SVT procedures (120 AVNRT, 91 AFL, 32 AP, 11 AT and 12 other right atrial procedures). In all cases, diagnostic EP and ablation catheters were positioned using a low fluoroscopic electroanatomic guided approach. The mean fluoroscopy time needed for each procedure was 55±128 s. The median reconstructed RA volume was 92 [63–131] ml in a median mapping time of 11 [7–17] min. The median number of radiofrequency ablations to terminate each arrhythmia was 6 [3–12] (total RF delivery time of 291 [180–505] s). Sixty-five percent of the procedures (n=174) were completed with less than 10 s of fluoroscopy. Low fluoroscopy approach with less than 10 s (minimal fluoroscopy approach) was most frequently obtained in case of AVNRT (91, 76%) compared to other arrhythmias' ablation (83, 57%, p=0.001) Achievement of a minimal fluoroscopic approach was not affected by operator's experience (65% vs 66%, p=1.00, respectively within physician with more or less of 10 years of active practice), whereas it was affected by presence of a fellow in training during the procedure (72% without fellow vs 26% with fellow, p&lt;0.0001). A 100% rate of acute success was observed, and no procedure-related complications occurred. At multivariate logistic regression analysis adjusted for baseline confounders, both the total number of RF ablations (OR: 0.93 (95% CI:0.88 to 0.96; p=0.0053) and the presence of a fellow in training during the procedure (OR: 0.29; 95% CI: 0.1 to 0.87; p=0.0278) had an inverse association to the achievement of a minimal fluoroscopic approach.

Conclusions

In our preliminary experience, arrhythmias' ablation through minimal fluoroscopy approach with the use of a novel ablation technology seems to be safe, feasible, and effective in common right atrial arrhythmias. Use of fluoroscopy can be dramatically reduced in most cases, without any reduction of the safety and acute effectiveness profile.

Funding Acknowledgement

Type of funding source: None

Evaluation of Dietary Administration of Chestnut and Quebracho Tannins on Growth, Serum Metabolites and Fecal Parameters of Weaned Piglets

In pig livestock, alternatives to in-feed antibiotics are needed to control enteric infections. Plant extracts such as tannins can represent an alternative as a natural source of functional compounds. The aim of this study was to evaluate the in vitro digestibility and in vivo effects of oral supplementation of combined chestnut (Ch) and quebracho (Qu) tannins in order to establish if they can induce a positive effect on weaned piglets' performance, metabolic status and fecal parameters. In vitro digestibility (dry matter, DM) of diets was calculated using a multi-step enzymatic technique. In vitro digested diet samples were further tested on an intestinal porcine enterocyte cell line (IPEC-J2). Weaned piglets (n = 120; 28 ± 2 day old) were randomly allotted to two groups (12 pens in total with 10 pigs per pen): control (Ctrl) and treatment (Ch/Qu). After one week of adaptation (day 0), 35-day-old piglets in the Ctrl group were fed a Ctrl diet and the Ch/Qu group were fed with 1.25% Ch/Qu for 40 days. Body weight and feed intake per pen were recorded weekly. At day 40, blood and fecal samples were collected. Principal metabolic parameters were evaluated from blood samples by enzymatic colorimetric analysis. Total phenolic compounds, urea, and ammonia in feces were analyzed (Megazyme International, Bray, Ireland). In vitro digestibility and cell viability assays showed that the inclusion of 1.25% Ch/Qu slightly reduced diet digestibility compared with the Ctrl diet, while intestinal cell viability was not altered with low concentrations of Ch/Qu digesta compared with Ctrl. In vivo results did not show any adverse effects of Ch/Qu on feed intake and growth performance, confirming that dietary inclusion of Ch/Qu at a concentration of 1.25% did not impair animal performance. The decreased diet DM digestibility in the Ch/Qu diet may cause increased serum concentration of albumin (Ctrl: 19.30 ± 0.88; Ch/Qu: 23.05 ± 0.88) and albumin/globulin ratio (Ctrl: 0.58 ± 0.04; Ch/Qu: 0.82 ± 0.04), but decreased creatinine (Ctrl: 78.92 ± 4.18; Ch/Qu: 54.82 ± 4.18) and urea (Ctrl: 2.18 ± 0.19; Ch/Qu: 0.95 ± 0.19) compared with Ctrl. Pigs in the Ch/Qu group contained higher (p < 0.05) concentrations of fecal phenolic compounds and nitrogen than the Ctrl group, while fecal ammonia and urea were not affected by tannins. In conclusion, Ch/Qu tannin supplementation did not influence growth performance. Although lower digestibility was observed in the diet supplemented with Ch/Qu tannins, Ch/Qu supplementation did not show any adverse effect on intestinal epithelial cell viability.

P1447Use of novel local impedance-based catheter in typical right atrial flutter ablation: preliminary data from a multicenter Italian study

Funding Acknowledgements

NO FUNDING

Background

Many studies demonstrated the importance of an optimal tissue contact to obtain safe and effective lesions and to improve the clinical outcome in ablation of cavotricuspid isthmus (CTI) for typical right atrial flutter (AFL). Data about a novel technology able to measure local tissue impedance (LI) providing a measure of tissue characteristics and lesion formation is still lacking in right atrium or CTI working.

Purpose

This analysis explores the relationship between LI measures and ablation spot lesion locations during ablation of CTI in common AFL patients (pts).

Methods

Consecutive pts undergoing AFL ablation from the CHARISMA registry were included. A novel RF ablation catheter with dedicated algorithm (DirectSense - DS -) was used to measure LI at the distal electrode of this catheter. Each targeted spot was characterized in terms of LI parameters during RF delivery at the lateral, intermediate and posterior portions of the CTI. Successful single RF ablation was defined according with a reduction of voltage (RedV) by at least 50% or split in two separate potentials (SPL). Ablation endpoint was the creation of bidirectional conduction block across the isthmus.

Results

A total of 135 ablation spot lesions were delivered in 20 pts (median 5 [3-11] lesions per pt): 7 (5%) at lateral, 88 (65%) at intermediate and 40 (30%) at posterior portions of the CTI. Acute success was obtained in all cases and no complications were observed. The median ablation time was 26 [17 – 36] seconds per lesion. 100 (74%) and 51 (38%) ablation spots were effective according with RedV or SPL, respectively. The mean LI was 106 ± 15Ω prior to ablation and 93 ± 13Ω after ablation (p &lt; 0.0001, mean absolute LI drop 14 ± 7Ω, mean percentage LI drop 13%±6). Effective ablation spots showed a higher absolute impedance drop (15 ± 7Ω at effective RedV vs 9.6 ± 8Ω at ineffective RedV, p = 0.0001; 15.6 ± 7Ω at effective SPL vs 12.5 ± 7Ω at ineffective SPL, p = 0.0173) or % impedance drop (14%±6 at effective RedV vs 9%±7 at ineffective RedV, p &lt; 0.0001; 14.5%±6 at effective SPL vs 11.6%±6 at ineffective SPL, p = 0.0103) compared with ineffective sites. No significant differences were found in terms of starting LI, ending LI or LI drop among CTI areas. The percentage of LI drop was associated both with RedV (odd ratio 1.17 (95%CI: 1.08 to 1.26, p = 0.0001)) and with SPL (odd ratio 1.08 (1.02 to 1.14, p = 0.0132)).

Conclusion

In our preliminary experience, measured LI before and after RF delivery and LI drop appear to be consistent and homogeneous across different CTI ablation locations. The magnitude of the LI drop was associated with effective lesion formation and conduction block.

P1086Prevalence and predictors of left atrial thrombi in patients scheduled for electrical cardioversion of nonvalvular atrial fibrillation

Background

Transesophageal echocardiography (TEE) showed the presence of thrombi in 12 to 26% of patients with atrial fibrillation (AF).

Purpose

To assess clinical and echocardiographic variables associated with thrombi in the left atrium (LA) prior to electrical cardioversion in patients with nonvalvular atrial fibrillation (AF).

Methods

Cross-sectional study including 188 patients. Clinical and echocardiographic variables were analyzed. Qualitative variables are expressed in percentages and quantitative variables in mean and standard deviations. Qualitative variables were analyzed by the Chi square method. A value of p &lt;0.05 was considered statistically significant.

Results

Mean age was 60.7 ± 12.3 and 75.5% males. The mean CHA2DS2-VASc and HAS-BLED scores were 2.43 ± 1.6 and 1.06 ± 1. The percentage of paroxysmal AF was 49.7%, nonparoxysmal 23.2% and atrial flutter 27%. Mean ejection fraction (EF) was 52.2 ± 13%. The prevalence of thrombus was 12.3%.

Female gender (p = 0.0275), heart failure (p = 0.0006), CHA2DS2-VASc score ≥2 (p = 0.0015), EF &lt;50% (p = 0.0089), moderate/severe spontaneous echocardiographic contrast (p = 0.000042) and LA appendage emptying velocity ≤20 cm/sec (p = 0.0000001) are associated to the presence of thrombi in the LA. No thrombi were detected in patients with CHA2DS2-VASc score of 0.

History of previous anticoagulation for over thirty days or creatinine clearance &lt;56 ml/min were not predictors of LA thrombi.

Conclusion

Female gender, heart failure, EF &lt;50% and CHA2DS2-VASc score ≥2, emptying velocity of less than 20 cm/sec and spontaneous echocardiographic contrast were univariate predictors of thrombi in the LA. CHA2DS2-VASc score of 0 is a strong predictor of absence of thrombi.

P1452Low fluoroscopy approach with a novel ablation technology in right side procedures: a large multicenter experience from the CHARISMA registry

Funding Acknowledgements

NO FUNDING

Background

Electrophysiological studies and ablation procedures expose both physicians and patients to a significant amount of radiation. Nowadays, most of 3-D mapping systems allow for improved tracking of catheters with possible reduction in radiation exposure. No data exists on the ability to minimize fluoroscopy time and dose while using the Rhythmia mapping system.

Purpose

To report preliminary data on feasibility and safety of a low fluoroscopic approach using the Rhythmia mapping system in SVT procedures.

Methods

The CHARISMA study is a non-randomized, multicenter, prospective study in which consecutive patients indicated for arrhythmia were enrolled. For our purpose consecutive right-side procedures performed through a low fluoroscopy approach with the Rhythmia mapping system were analyzed. The mapping system was used to create the 3D geometry of chambers of interest and anatomic reference points and to visualize the catheters from the beginning to the end of the procedure. Fluoroscopy was used only if deemed necessary.

Results

204 unselected consecutive cases of SVT from 11 centers were included in the study (mean age = 55 ± 18 years, 53% male, 85 AVNRT, 75 AFL, 28 AP, 9 AT and 7 other right atrial procedures). In all the cases, diagnostic EP and ablation catheters were positioned using only the low fluoroscopic guided mapping approach. During the study, a total of 7157 s of fluoroscopy was needed in 204 patients (51 ± 137 s per procedure). One hundred fourty-one procedures (69%) were completed with less than 10 seconds of fluoroscopy, whereas in 169 (83%) of the cases the fluoroscopy time was lower than 60 seconds. Low fluoroscopy approach with less than 10 seconds was less frequently obtained in case of AFL (46, 61.3%) compared to AVNRT ablation (65, 76.5%, p = 0.041) whereas no differences were found comparing with AP (21, 75%, p = 0.248). The median reconstructed RA volume was 94[65-133] ml in a median mapping time of 11 [6-16] min. The median number of radiofrequency ablations to terminate each arrhythmia was 5 [3-12] (total RF delivery time of 293 [180-505] sec). A 100% rate of acute success was observed in our case series. No complications occurred.

Conclusions

In our preliminary experience, arrhythmias ablation through low fluoroscopy approach and the use of a novel ablation technology seems to be safe, feasible, and effective in common right atrial arrhythmias. Use of fluoroscopy can be nearly avoided in most cases, without any reduction of the safety and effectiveness profile.

Decoding collective communications using information theory tools

Organisms have evolved sensory mechanisms to extract pertinent information from their environment, enabling them to assess their situation and act accordingly. For social organisms travelling in groups, like the fish in a school or the birds in a flock, sharing information can further improve their situational awareness and reaction times. Data on the benefits and costs of social coordination, however, have largely allowed our understanding of why collective behaviours have evolved to outpace our mechanistic knowledge of how they arise. Recent studies have begun to correct this imbalance through fine-scale analyses of group movement data. One approach that has received renewed attention is the use of information theoretic (IT) tools like mutual information, transfer entropy and causation entropy, which can help identify causal interactions in the type of complex, dynamical patterns often on display when organisms act collectively. Yet, there is a communications gap between studies focused on the ecological constraints and solutions of collective action with those demonstrating the promise of IT tools in this arena. We attempt to bridge this divide through a series of ecologically motivated examples designed to illustrate the benefits and challenges of using IT tools to extract deeper insights into the interaction patterns governing group-level dynamics. We summarize some of the approaches taken thus far to circumvent existing challenges in this area and we conclude with an optimistic, yet cautionary perspective.

Isotopic biomonitoring of N pollution in rivers embedded in complex human landscapes

The dynamic and hierarchical structure of rivers, together with disruption of the natural river continuum by human activities, makes it difficult to identify and locate sources of nutrient pollution affecting receiving waters and observe its dispersion, thus impairing monitoring efforts. The identification of reliable indicators of anthropogenic nitrogen inputs in catchments is therefore key to achieving effective management of polluted rivers. We tested the capacity of N isotopic signatures (δ¹⁵N) of epilithon and snails to provide useful indications of organic and inorganic anthropogenic N inputs in three Mediterranean rivers differing in terms of surrounding land use and physicochemical conditions. We used a combined approach based on (i) analysis of nutrient concentrations in water, (ii) CORINE land cover classification and drainage patterns in catchments and (iii) isotopic analysis of river biota to verify whether isotopic variations were indicative of anthropic activities in the watershed, the associated alteration of water quality, and the consequent impact on snail abundance and diversity. Variation in the δ¹⁵N of epilithon within and between rivers reflected localised and diffuse N inputs from inorganic and organic sources. Negative epilithon δ¹⁵N values (<0‰) indicated inorganic pollution from agriculture. Values between 4‰ and 8‰ and those above 8‰ respectively indicated moderate organic pollution from urban areas, and high organic pollution, mostly from waste waters. The diversity and abundance of snails decreased with increasing water pollution. While their isotopic variations reflected between-river differences, they failed to indicate within-river variations in anthropogenic N inputs, since the proportion of epilithon in their diet varied along the rivers. Concluding, epilithon was a reliable indicator of anthropogenic N sources across a wide range of nutrient concentrations and anthropogenic inputs, and the proposed approach allowed us to determine the nature of nitrogen pollutants, their sources, location and dispersion along rivers embedded in complex human landscapes.

Typha latifolia and Thelypteris palustris behavior in a pilot system for the refinement of livestock wastewaters: A case of study

In animal livestock heavy metals are widely used as feed additives to control enteric bacterial infections as well as to enhance the integrity of the immune system. As these metals are only partially adsorbed by animals, the content of heavy metals in manure and wastewaters causes soil and ground water contamination, with Zn²⁺ and Cu²⁺ being the most critical output from pig livestock. Phytoremediation is considered a valid strategy to improve the purity of wastewaters. This work studied the effect of Zn²⁺ and Cu²⁺ on the morphology and protein expression in Thelypteris palustris and Typha latifolia plants, cultured in a wetland pilot system. Despite the absence of macroscopic alterations, remodeling of cell walls and changes in carbohydrate metabolism were observed in the rhizomes of both plants and in leaves of Thelypteris palustris. However, similar modifications seemed to be determined by the alterations of different mechanisms in these plants. These data also suggested that marsh ferns are more sensitive to metals than monocots. Whereas toleration mechanisms seemed to be activated in Typha latifolia, in Thelypteris palustris the observed modifications appeared as slight toxic effects due to metal exposure. This study clearly indicates that both plants could be successfully employed in in situ phytoremediation systems, to remove Cu²⁺ and Zn²⁺ at concentrations that are ten times higher than the legal limits, without affecting plant growth.