P-039 COMPOSITE PP/PLLA MONOFILAMENT 4DVENTRAL® PROMOTES AN ANTI-INFLAMMATORY RESPONSE FROM HUMAN MACROPHAGES IN VITRO

The repair of abdominal hernias with prosthetic mesh can significantly reduce the risk of hernia recurrence. A new type of hernia implants combines monofilaments, Polypropylene (PP) and a biobased and natural slowly bioabsorbable polymer, Poly-L-Lactic Acid (PLLA). The partially (60%) resorbable PLLA/PP and PP meshes manufactured by COUSIN Surgery are 4DVentral® and Biomesh P1®. The contribution of PLLA in regulated inflammatory response and in enhancing abdominal repair remains unknown. Inflammation has a functional role during tissue regeneration process. An abnormal macrophage response characterized by an uncontrolled release of pro-inflammatory cytokines, chemokines, and tissue-degrading enzymes has been shown to be responsible for postoperative complications. In contrast, the angiogenic and tissue remodeling activities of the alternative anti-inflammatory M2 macrophages have potential use in tissue regenerative. Here, the characterization of the inflammatory response of human macrophages in vitro regarding 4DVentral® compared to Biomesh P1® was performed. Human monocytic THP-1 cells were differentiated into macrophages and polarized in M1 macrophages by incubation with IFN-γ and LPS or not (M0 macrophages). We found that 4DVentral® induced higher secretion of anti-inflammatory cytokines (IL-10 and Il1-RA) compared to PP Mesh in M0 macrophages. Interestingly, the secretion of pro-inflammatory cytokine IL-6 in M1 macrophages was dramatically reduced in the presence of 4DVentral® mesh compared to PP Biomesh P1®. However, the secretion of IL-10 was significantly increased with 4DVentral®. The composite PLLA/PP monofilament 4DVentral® positively drives human macrophages to an anti-inflammatory profile, resolving inflammation and promoting tissue repair.

Quantifying the variability of bipolar voltage amplitude with sensing angle in residual conduction isthmuses in atrial scar

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

The angle between the activation wavefront and bipole may conceal the conduction isthmus in conventional bipolar voltage mapping, but the extent of variability of electrogram (EGM) voltage amplitude with directional changes has not been quantified.

Purpose

Using a well-defined model of discrete atrial conduction, we sought to use Omnipolar Technology (OT) to assess variability of voltage amplitude as a function of sensing angle, in sites of residual conduction and scar tissue.

Methods

During redo pulmonary vein isolation (PVI) procedures, baseline voltage maps were acquired during coronary sinus pacing (500 ms) using a rectangular 16-pole catheter (HD Grid). During retrospective analysis with OT research software, all EGM’s ≤1 cm radius from the site of PVI were classified as GAP (vs No-GAP; Panel A) The variability of voltage amplitude (OT-ΔV) with sensing angle (θ) was computed as the difference between the maximum and minimum voltages (OT-Vmax - OT-Vmin), in both GAP and No-GAP subregions (Panels A & B).

Results

23 GAP sites were identified in 12 of 15 consecutive patients studied. 3464 EGM’s (1386 GAP vs 2078 No-GAP) were analyzed. Global mean OT-ΔV was 0.46±0.80 mV. GAP regions showed significantly (P<0.0001) higher OT-ΔV as compared with No-GAP regions (0.80±1.03 mV vs 0.24±0.47 mV respectively; Panel C) The mean Δθ angle for OT-ΔV was similar in both GAP and No-GAP regions (88.6±11.3° vs 88.0±13.6°, P=0.1; Panel D).

Conclusion

The variability of voltage amplitude as a function of bipole orientation can be significant, especially in GAP regions (0.80±1.03 mV). (2) OT-ΔV holds promise for identification of residual conduction within atrial scar tissue.

Influence of atrial cycle length and site of origin on the peak frequency of bipolar electrograms to discriminate isthmus conduction in atrial scar

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Peak frequency (PF) of conventional bipolar electrograms is a novel parameter which may distinguish between near-field (NF) and far-field (FF) signals. However, the influence of activation rate and the direction of the activation front on it is unknown.

Purpose

1. To study the influence of atrial cycle length and wavefront origin on PF to detect residual conduction in a well-defined model of narrow isthmus of conduction such as subacute pulmonary vein (PV) reconnection following atrial fibrillation ablation. 2. To compare this influence with that found for Bipolar voltage (BiV).

Methods

Baseline maps were acquired in redo PV isolation (PVI) procedures with a 16-pole grid catheter (HD-Grid) during low rate sinus rhythm (SR), low rate coronary sinus pacing at 500 ms cycle length (CSLR) and high rate coronary sinus pacing at 300 ms cycle length (CSHR). PFs were retrospectively computed. PVI sites requiring ≤3 radiofrequency applications were included, with EGMʼs ≤1cm from the PVI site classified as GAP (vs >1cm, No-GAP).

Results

28 GAPs were found in 12 of 14 consecutive patients in the study. 3976 EGMʼs (1547 GAP vs 2429 No-GAP) were analyzed. In both GAP and No-GAP, PF was similar in SR vs CSLR (GAP: 363±132 Hz -SR vs 345±135 Hz -CSLR, P=NS ; No-GAP: 196±110 Hz -SR vs 181±116 Hz -CSLR, P=NS). PF was slightly higher for CSLR vs CSHR. (GAP: 345±135 Hz -CSLR vs 317±154 Hz -CSHR, P<0.001; No-GAP 181±116 mV -CSLR vs 162±129 mV -CSHR, P<0.01). (Panel A). BiV was significantly higher in SR vs CS pacing but similar between CSLR and CSHR (GAP: 1.86±2.11 mV -SR vs 0.87±1.19 mV -CSLR vs 0.74±0.92 mV -CSHR, P= NS, No-GAP: 0.62±1.22 mV -SR vs 0.33±0.68 mV - CSLR vs 0.27±0.48 mV - CSHR, P=NS. (Panel B). ROC GAP discrimination for PF was similar between SR and CSLR (AUCʼs: 0.86-SR, 0.84-CSLR) and slightly lower for CSHR (AUC: 0.81) with optimal cutoffs of 260, 240 and 220 Hz, respectively. ROC GAP discrimination for BiV was lower vs PF in all rhythm modes (AUCʼs: 0.77-SR, 0.74-CSLR, 0.75-CSHR), with optimal cutoffs of 0.3, 0.2 and 0.15 mV, respectively.

Conclusion

ROC gap discrimination was significantly higher for all rhythm modes with PF vs BiV. PF showed slightly decreasing cutoff values for SR, CSLR and CSHR respectively, whereas BiV showed a greater relative decrease in cutoffs for SR, CSLR and CSHR.

Validation of the peak frequency of bipolar electrograms for detection of residual conduction in atrial scar tissue

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Activation and voltage (Bi-V) maps (Panel A) based on conventional bipolar electrograms (EGMs) are influenced by both near-field (NF) and far-field (FF) EGM components. This represents a limitation in the accurate detection of residual conduction within regions of scar. Peak frequency (PF) EGM analysis may better distinguish NF from FF activation vs conventional detection methods. (Panels B & C)

Purpose

1. To validate the use of PF to detect residual conduction in a well-defined model of narrow isthmus of conduction such as subacute pulmonary vein (PV) reconnection following atrial fibrillation ablation. 2. To compare discrimination value of PF and conventional Bi-V to detect such isthmuses.

Methods

Bi-V and activation maps were acquired during redo PV isolation (PVI) procedures using a rectangular 16-pole catheter (HD-Grid). LA-PV conduction was assessed during coronary sinus (CS) pacing (500ms cycle length). Any conduction gap (GAP) site at which PVI was established using ≤3 focal radiofrequency applications was analyzed. (Panel A) EGMʼs ≤1cm from the site of PVI were classified as GAP (vs EGMʼs ≥1cm - No-Gap). (Panel B)

Results

28 GAPs were found in 12 of 14 consecutive patients in the study. 3,976 EGMʼs (1,547 GAP vs 2,429 No-GAP) were analyzed. GAP regions showed significantly higher PF than No-GAP regions (345 ±135 vs 181±116 Hz, P<0.0001) (Panel E). GAP regions also showed significantly higher BiV than No-GAP regions

(1.86±2.11 mV vs 0.62±1.22 mV, P<0.0001) (Panel D). ROC curves for GAP vs No-GAP discrimination were better for PF (AUC 0.84) than for Bi-V (AUC 0.74) with optimal cutoffs of 240 Hz and 0.2 mV, respectively. (Panel F)

Conclusion

PF better detects residual conduction within an atrial scar region than conventional Bi-V. The PF cutoff value for gap discrimination in the PV antra is 240 Hz.

Systematic identification of low voltage-high frequency electrogram zones at sites of left atrial reentrant tachycardia termination

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Localization of the narrow isthmus of conduction of left atrial local and macro reentrant tachycardia (LAMRT) circuits within scar tissue is challenging. (Panel A). Near-field (NF) electrograms are often obscured by and difficult to distinguish from far-field (FF) activation. The peak frequency (PF) associated with bipolar electrograms is a novel parameter which may distinguish between NF and FF signals. (Panel B). However, the potential value of PF for LAMRT ablation has never been evaluated.

Purpose

1) To quantify the percentage of LA surface with low voltage (LV) and NF signals. 2) To study the proportion of LAMRT ablation sites which were located within a LV-NF region or in the vicinity of it (<10 mm away).

Methods

LART bipolar voltage and activation maps were generated with a 16-pole grid catheter (HD-Grid) during tachycardia. (Panels A,B). PF maps were retrospectively computed (Panels C,D). LV zones were defined according to a cutoff <0.3mV. Four different PF cut-off values (>250, >300, >350 and >400 Hz) were assessed in the delineation of overlapping LV-NF regions. (Panel E)

Results

16 consecutive patients with 24 LAMRT’s targeted for ablation were prospectively enrolled. 21/24 LAMRT’s were terminated by radiofrequency application. (Panel F). The LV area represented 47.7±14% of the LA surface. The LV-NF area represented 8.2±6.2%, 5.2±5.4%, 3.4±7.4% and 3.3±4.1% of the LA surface by using 250, 300, 350, and 400 Hz PF cutoffs respectively. There were 2.1±1 (range 0-3), 0.9±0.8(range 0-3), 0.5±0.6 (range 0-2) and 0.5±0.6 (range 0-2) LV-NF areas per patient using 250, 300, 350 and 400 Hz PF cutoffs respectively. At the optimal PF cutoff > 250Hz and voltage < 0.3mV, the site of tachycardia termination by radiofrequency application was found inside of a LV-NF region in 13/21 LAMRTs (sensitivity 68.4%), and within 1cm of a LV-NF region in 19/21 LAMRTs (sensitivity 89.5%) respectively.

Conclusion

1. Left atrial reentry termination sites by radiofrequency application are often within or nearby LV-NF areas as identified by the PF and voltage analysis of bipolar electrograms. 2. Beyond conventional substrate mapping, the systematic identification of high frequency activity within the low voltage zone holds promise for rapid identification of isthmus conduction critical to LAMRTs.

Characterization of conduction gaps at the pulmonary vein antra by omnipolar voltage mapping

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Abbott provided some software to perform special maps

Introduction

Voltage mapping of atrial tissue may be influenced by the direction of the activation front. Omnipolar electrograms may result in better characterization of the atrial tissue. However, little is known about characterization of the pulmonary vein (PV) antra with omnipolar mapping in patients with recurrent atrial fibrillation (AF) following PV isolation (PVI). 

Purpose

To study differences in voltage between regions with (Gap) and without (No-Gap) conduction recurrence at the PV antra by both omnipolar and conventional bipolar mapping in redo PVI procedures.

Methods

Single centre prospective study  of consecutive patients who underwent a redo PVI procedure for AF ablation. Activation and voltage bipolar maps were developed on a electroanatomical system (Ensite Precision) by a steerable catheter with a 16 grid-patterned electrode configuration (HD-Grid) during coronary sinus pacing at both 500 and 300 ms.  Precise location of conduction gaps in the PV antra was attempted by atrial and PV pacing. Only conduction gaps that were ablated by ≤3 focal radiofrequency applications were included in the analysis. Electrograms recorded within 1 cm at both sides of the RF application site were considered related to the gap region. Off-line omnipolar voltage maps were developed with a dedicated experimental software after the procedure .

Results

11 patients were included in the study and 18 gaps were found in 9 patients. 6762 (2688 Gap and 4074 No-Gap)  electrograms were analyzed. Compared with No-Gap PV regions, Gap regions showed significantly (P < 0.0001) higher voltages by omnipolar mapping (0.3 ± 0.6 mV vs 1.1 ± 1.4 mV)  and by absolute (0.2 ± 0.5 mV vs 0.8 ± 1.2 mV),  grid-along (0.3 ± 0.5 mV vs 0.8 ± 1.2 mV) and grid-across  (0.3 ± 0.5 mV vs 0.8 ± 1.1 mV) bipolar mapping.  Omnipolar mapping resulted in higher voltage electrograms when compared with absolute bipole, longitudinal and horizontal bipolar electrograms (P < 0.0001). ROC curves (figure) to differentiate between Gap and No-Gap regions were slightly better for omnipolar electrograms (AUC 0.79) than for conventional grid -along or grid-across bipolar mapping (AUC 0.76 and 0.77) with the best discrimination value of 0.3 and 0.2 mV respectively.  Conclusion: There are significant differences in voltage between conduction Gap and No-Gap regions at the PV antra which are more apparent with omnipolar than with conventional bipolar mapping. 0.3 mV and 0.2 mV values are the best to differentiate between PV conduction Gap and No-Gap regions with ominpolar and conventional mapping respectively

A case report of Lemierre's Syndrome associated with dental sepsis

INTRODUCTION

Lemierre's syndrome is a potentially fatal condition characterised by spread of an oropharyngeal infection, resulting in thrombosis of the internal jugular vein. This leads to septicaemia and possible metastatic abscesses.

CASE PRESENTATION

We discuss the case of a previously healthy 17-year-old male who developed Lemierre's syndrome following dental sepsis. He presented with bilateral submandibular and submental swelling extending into the neck and chest. His management included a tracheostomy; incision and drainage of the abscesses; drainage of a pleural effusion and prolonged anticoagulant therapy.

CONCLUSION

The incidence of Lemierre's disease appears to be increasing and early diagnosis is essential. A high index of suspicion is needed in cases of oropharyngeal infection followed by fever, tender swelling of the neck and dysphagia - especially in young patients.

Control of starch composition and structure through substrate supply in the monocellular alga Chlamydomonas reinhardtii

In Chlamydomonas, as in higher plants, synthesis of ADP glucose catalyzed by ADP-glucose pyrophosphorylase is rate-limiting for the building of starch in the chloroplast. We have isolated disruptions of the STA1 ADP-glucose pyrophosphorylase structural gene that rendered the enzyme less responsive to the allosteric activator 3-phosphoglycerate. The structure and composition of the residual starch synthesized by all mutants of the STA1 locus is dramatically altered. The residual polysaccharide is shown to be devoid of amylose despite the presence of granule-bound starch synthase, the amylose biosynthetic enzyme. In addition, the fine structure of the mutant amylopectin revealed the presence of an altered chain-length distribution. This distribution mimicks that which is observed during growth and photosynthesis and differs markedly from that observed during storage. We therefore propose that low nucleotide sugar concentrations are either directly or indirectly responsible for the major differences observed in the composition or structure of starch during storage and photosynthesis.

Toxoplasmosis masking non-Hodgkin's lymphoma: a case report

A 39-year-old female with persistent cervical lymphadenopathy is reported. Initial investigations resulted in a diagnosis of toxoplasmosis, but subsequently the patient proved to have high grade immunoblastic non-Hodgkin's lymphoma. This paper highlights the difficulties in accurately diagnosing some cases of either toxoplasmosis or lymphoma, and briefly mentions some of the ongoing technical advances which will increase diagnostic specificity and sensitivity by early detection of genetic mutations.