Fulguration Research Articles

Clinical Radiofrequency Ablation Outcomes of Combined Sensory Nerve Branch and Dorsal Entry Root Zone Complex Lesions for Sacroiliac Joint Complex Pain.

Chronic lower back pain (LBP) with or without leg pain (LP) is the most commonly reported anatomical site of pain among Canadian adults with chronic pain. A common cause for LBP and LP arises from dysfunction of the sacroiliac joint (SIJ) complex. When conventional medical management or rehabilitative efforts for SIJ-related LBP and LP fail to provide analgesia, pulsed radiofrequency (PRF) and/or radiofrequency ablation (RFA) of the dorsal entry root zone complex lesions (DREZC) and/or their more peripheral branches can also be a suitable means for treatment. Both PRF and RFA are interventional techniques that utilize heat to attenuate or ablate transmission of painful signals, respectively. The purpose of this chart review is to explore the clinical outcomes of patients experiencing SIJ-related pain who have undergone procedures with combined sensory nerve branch RFA and DREZC PRF lesions targeting the SIJ complex. Following institutional review board approval, a retrospective chart review was performed from June 2018 to February 2021 for patients with LBP and/or LP refractory to physical rehabilitative efforts and medical management that underwent combined PRF and RF treatments for a diagnosis of SIJ complex pain. RF and PRF procedures were anatomically guided with the addition of sensory stimulation to ensure appropriate needle placement. Charts were reviewed for percentage of analgesia at final follow-up, duration of effect, degree of analgesia, patients' functional improvements, and changes in medication use patterns. Data was reviewed from 180 patients with LBP or LP who underwent combined PRF and RF treatments for a diagnosis of SIJ complex pain. The group consisted of 69 men and 111 women with a mean age of 59years. All patients had lesions to their dorsal roots and/or branches (lumbar medial and sacral lateral), as determined using their pain profile as well as sensory stimulation. In the sample of 180 patients a total of 276 SIJs were treated over the period of data collection. Overall, 85.0% (n = 234) of procedures were considered successful with more than 50% analgesic relief at final follow-up. Of 234 successful outcomes, 110 reported ongoing analgesia (mean = 80.3% pain relief, SD ± 18.0) on the last date of follow up (mean = 53.2days, SD ± 41.8) prior to being lost to follow-up. For patients not lost to follow-up, the mean amount of analgesia was reported to be 83.9% with an average duration of 86.3days. Among all treatments, 6.9% (n = 19) provided no analgesic effect. Among the successful procedure outcomes, 54.4% (n = 150) reported increased activity/mobility, 24.3% (n = 67) reported improved sleep, 49.3% (n = 136) reported improved mood, and 11.6% (n = 32) reported decreased medication usage. Nine patients reported complications following the procedure. Complications included transient soreness, bruising, tenderness, myofascial pain, and two mild vagal responses without lasting sequelae. This review suggests that combined sensory nerve branch RFA and DREZC PRF lesions targeting the SIJ complex is a suitable intervention to treat SIJ-related LBP and/or LP refractory to physical rehabilitative efforts and medical management. Approximately 85% of these cases were successfully treated with the majority of patients report lasting analgesic effects with minimal complications, supporting the use of sensory stimulation-guided combined RF and PRF lesions for treatment of refractory SIJ complex pain.

Contact force guided radiofrequency current application at developing myocardium

Catheter contact is akey determinantfor lesion size in radiofrequency catheter ablation (RFA). Monitoring of contact force (CF) during RFA has been shown to improve efficacy of RFA in experimental settings as well as in adult patients. Coronary artery narrowing after RFA has been described in experimental settings as well as in children and adults and may be dependent from catheter contact. The value of CF monitoring concerning these issues has not been systematically studied yet. Value of high versus low CF during RFA in piglets was studied to assess lesion size and potential coronary artery involvement mimicking RFA in small children. RFA with continuous CF monitoring was performed in 24 piglets (median weight 18.5 kg) using a 7 F TactiCath Quartzradiofrequency (RF) ablation catheter (Abbott). A total of 7 lesions were induced in each animal applying low (10-20 g) or high (40-60 g) CF. RF energy was delivered with a target temperature of 65°C at 30 W for 30 s. Coronary angiography was performed prior and immediately after RF application. Animals were assigned to repeat coronary angiography followed by heart removal after 48 h (n = 12) or 6 months (n = 12). Lesions with surrounding myocardium were excised, fixated, and stained. Lesion volumes were measured by microscopic planimetry. A total of 148 RF lesions were identified in the explanted hearts. Only in the subset of lesions at the AV annulus 6 month after ablation, lesion size and number of lesions exhibiting transmural extension were higher in the high CF group compared to low CF. In all other locations CF had no impact on lesion size and mural extension after 48 h as well as after 6 months. Additional parameters such as lesion size index and force time integral were also not related to lesion size. Coronary artery damage was present in two animals after 48 h and in one after 6 months and was not related to CF. In our experimental setting, lesion size in piglets was not related to catheter CF. Transmural extension of the RF lesions involving the layers of the coronary arteries was frequently noted irrespective of CF. Coronary artery narrowing was present in 3/24 animals and was not related to CF. In infants and toddlers, low CF (10-20 g) may be of adequate effect. Impact of CF monitoring during conventional RF ablation in children requires further investigation.

Electrode tissue coupling is a new main determinant of RF lesion creation, experience from a cardiac animal model

Abstract Funding Acknowledgements Type of funding sources: None. Background Radiofrequency (RF) current is a classic ablation technology used in the EP lab. By now it is assumed that RF lesion size is mainly determined by RF power, duration and contact force. This ex vivo animal model study shows that a new parameter - "electrode tissue coupling" (ETC) - plays an additional major role in RF lesion creation. The ETC level describes the amount of electric contact between the RF electrode and cardiac tissue: In minor ETC levels, only the distal electrode connects to tissue. In full ETC levels, the whole RF electrode is embedded in cardiac tissue. Methods RF-lesions were created using an ex vivo porcine cardiac model. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. A RF power of 20W, 30W, 40W, and 50W was used. The ETC levels were systematically varied between minor and full coupling. All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during application of RF-current, enabling real-time correlation of RF parameters and lesion size. Results In total, 1923 measurements during application of RF-current were analyzed. In ETC III (full tissue coupling), lesions became significantly wider and deeper. In 20W ablations, lesion diameters were significantly (1.68 fold) larger when applying ETC III instead of ETC I. This relation was found in variations of RF parameters (Table 1). Interestingly, baseline local impedance and local impedance drop showed a high correlation with selected ETC levels. The average baseline local impedance in ETC I was 207.2 Ohm, compared to 267.3 Ohm in ETC III (p < 0.01). Discussion In addition to by now known parameters (power, duration, contact force), electrode tissue coupling is a main determinant of lesion size. Higher ETC levels result in higher amounts of RF current going into adjacent tissue instead of current dissipation into the blood pool. In clinical practice, the ETC level can be predicted by baseline local and global impedance. Observation of these parameters should become clinical practice during RF ablation.

Correlation of local impedance, global impedance and contact force with resulting lesion size in RF ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background During clinical application of RF-energy, several parameters are constantly observed, e.g. RF time, power, global impedance and temperature. The new parameter "local impedance" is gaining importance and might be a possible real-time marker for predicting long-lasting RF-lesions and increasing safety. The aim of this study was to investigate the correlation between local and global impedance as well as RF power and contact force. Methods RF-lesions were created using an ex vivo model with porcine cardiac preparations. These were put in a saline-filled container with a dispersive electrode. Global impedance was held at 120 Ohm by adjusting saline and water. Additionally, a heated thermostat and a circulation pump were installed to imitate blood flow. RF-lesions were produced with different settings of energy and contact force (20, 30, 40 and 50 watts; contact force of 0-5g, 10-15g and 20-25g). While creating the lesions, global and local impedance, temperature, energy and RF time were documented, as well as the current lesion width and depth. Local and global impedance drops were calculated as the difference between baseline impedance and current impedance. Results In total, 1223 measurements were made during application of RF-energy. 6 steam pops occurred. Contact force, local and global impedance changes showed highly significant correlations with lesion depth and diameter. Amongst analyzed values, local impedance drop showed highest correlation with lesion diameter and depth (r = 0,391 and 0,613; p<0,001). Visualized in Figure 1 and 2, global and local impedance correlate with lesion diameter and depth. Discussion Local impedance was found to be a suitable real-time marker for lesion size, showing significantly higher correlations with RF lesion size than contact force and global impedance. Further investigation is necessary to find a cut off for a safe but long-lasting RF-lesion.

MP02-16 LONG-TERM OUTCOMES AFTER ELECTROFULGURATION FOR ANTIBIOTIC-REFRACTORY RECURRENT URINARY TRACT INFECTIONS

You have accessJournal of UrologyCME1 May 2022MP02-16 LONG-TERM OUTCOMES AFTER ELECTROFULGURATION FOR ANTIBIOTIC-REFRACTORY RECURRENT URINARY TRACT INFECTIONS Shivani Gaitonde, Alana L. Christie, and Philippe E. Zimmern Shivani GaitondeShivani Gaitonde More articles by this author , Alana L. ChristieAlana L. Christie More articles by this author , and Philippe E. ZimmernPhilippe E. Zimmern More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002514.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Antibiotic-refractory recurrent urinary tract infections (rUTI) are challenging to manage. Prior studies have shown that in well-selected patients, electrofulguration (EF) of chronic trigonitis may disrupt a potential nidus of rUTI [1,2]. We report on long-term outcomes for women with at least five years of follow-up after EF. METHODS: Following IRB approval, we analyzed a cohort of non-neurogenic women with >3 symptomatic UTI/yr and cystoscopic evidence of trigonitis, who underwent EF from 2006 to 2011. Those with alternate identifiable source of rUTI (upper tract, prior mesh, stage 2 prolapse) or less than 5yr follow-up were excluded. Preoperative characteristics (demographics, antibiotic regimens, UTI/yr) were reported. The primary outcomes at 5yr post-EF were clinical cure (0-1 UTI/yr), improvement (2/yr) or unchanged (>3/yr), and endoscopic cure (no lesions on cystoscopy), improvement (persistent trigonitis), or progression (lesions beyond the trigone). Secondary outcomes were need for antibiotics prophylaxis or repeat EF. RESULTS: Of 44 women, median age was 65yr (56-74), parity was 2 (1-3), and BMI was 24.2 (20.7-29.3). Mean follow-up was 117 months (60-180); 22 women had >10yr follow-up. Prior to EF, 80% used daily antibiotic suppression, 9% used post-coital prophylaxis, and 14% used additional self-start therapy if symptomatic. 6 patients required IV antibiotics for pyelonephritis or multidrug resistance. By 5yr post-EF, 57% were clinically cured, 32% were improved, and 11% were unchanged. 86% had endoscopic cure, 7% had improvement and 7% had progression. 45% of all women did not need any antibiotic regimen, 35% used self-start therapy as needed, 18% used daily prophylaxis, and 9% used post-coital prophylaxis. All clinically cured patients also had endoscopic cure, and 79% did not use any antibiotic therapy. In contrast, both improved and unchanged patients were more likely to continue post-EF prophylaxis (p<0.05) and have endoscopic persistence or progression (p<0.05). 80% of clinically unchanged patients underwent repeat EF; median time to repeat EF was 12 months (6-58). CONCLUSIONS: In women with over 5yr follow-up after EF for antibiotic-refractory rUTI and trigonitis, there appears to be durable clinical cure and improvement, with decreased need for long-term antibiotics.

PO-695-04 CORRELATION OF LOCAL IMPEDANCE, GLOBAL IMPEDANCE AND CONTACT FORCE WITH RESULTING LESION SIZE IN RF-ABLATION

During clinical application of RF-energy, several parameters are constantly observed, e.g. RF time, power, global impedance and temperature. The new parameter “local impedance” is gaining importance and might be a possible real-time marker for predicting long-lasting RF-lesions and increasing safety. The aim of this study was to investigate the correlation between local and global impedance as well as RF power and contact force. RF-lesions were created using an ex vivo model with porcine cardiac preparations. These were put in a saline-filled container with a dispersive electrode. Global impedance was held at 120 Ohm by adjusting saline and water. Additionally, a heated thermostat and a circulation pump were installed to imitate blood flow. RF-lesions were produced with different settings of energy and contact force (20, 30, 40 and 50 watts; contact force of 0-5g, 10-15g and 20-25g). While creating the lesions, global and local impedance, temperature, energy and RF time were documented, as well as the current lesion width and depth. Local and global impedance drops were calculated as the difference between baseline impedance and current impedance. - In total, 1223 measurements were made during application of RF-energy. 6 steam pops occurred. Contact force, local and global impedance changes showed highly significant correlations with lesion depth and diameter. Amongst analyzed values, local impedance drop showed highest correlation with lesion depth and diameter (p-value <0,001 each). Visualized in Figure 1 and 2, global and local impedance correlate with lesion diameter and depth. Figure 1. Correlation of lesion size and local impedance drop. Light blue = Depth. Darker Blue = diameter. Figure 2. Correlation of lesion size and global impedance drop. Light blue = Depth. Darker Blue = diameter. Local impedance was found to be a suitable real-time marker for lesion size, showing significantly higher correlations with RF lesion size than contact force and global impedance. Further investigation is necessary to find a cut off for a safe but long-lasting RF-lesion.

Cranberry Supplement, D-Mannose, and Other OTC Modalities for Prevention of Recurrent UTI in Women Post-Electrofulguration.

PurposeTo assess patient reliance on various over-the-counter (OTC) modalities used for prevention of recurrent urinary tract infection (RUTI) after electrofulguration (EF).Patients and MethodsFollowing IRB approval, qualifying women were offered a short survey over the phone by a medical researcher to collect information about their use of various OTC modalities for prophylaxis of RUTI. Data was compared between two cohorts, ≥70 years old and <70 years old, using chi-squared and Student’s t-tests.ResultsFrom a database of 324 patients, 163 accepted the interview. 17% (28/163) reported current use of cranberry supplements, 10% (16/163) D-mannose supplements, and 42% (69/163) another non-prescription modality for RUTI prophylaxis. The non-geriatric (<70 years old) cohort spent, on average, $80 less annually on cranberry/D-mannose supplements (P=0.043) than the geriatric cohort and were more likely to use non-prescription modalities for the prevention of UTI (52% vs 30%; P=0.0061). Individuals using D-mannose were also much more likely to purchase their product online compared to those using cranberry supplements (85% vs 56%). Across all modalities, the perceived benefit difference in reducing UTI/year ranged from a median of 0 for Pyridium® (phenazopyridine hydrochloride) to four for probiotics, with D-mannose and cranberry at two/year, and those increasing daily fluid consumption at 2.5 fewer UTI/year.ConclusionContinued use of non-prescription modalities for RUTI prophylaxis were common among women with an EF history, but varied based on age groups. Across both age cohorts, annual expenditure and perceived benefit also varied among different OTC prophylactic modalities. Awareness of type and method of OTC modality implementation by patients with RUTI is essential to aligning use with current field recommendations.

Does Urinary pH and Diet Influence the Rate of Urinary Tract Infection Recurrence After Electrofulguration in Women With Antibiotic-Recalcitrant Recurrent Urinary Tract Infections?

ObjectivesTo assess if urine acidity may be preventative against urinary tract infection (UTIs) and affected by diet. Our goal was to evaluate the effect of urine pH on the rate of recurrent UTIs (RUTIs) after electrofulguration (EF) in 3 groups of women with different urine pH ranges as well as the relation between their diet composition and urine pH. MethodsIn a prior IRB-approved prospective study, women recorded urinary pH 4 times a day and diet for a week. Three urinary pH groups were identified: never below 6, never above 6, and above and below 6. In this study, a 3-day diet analysis involved categorizing different foods by acidity based on pH food charts and calculating amounts consumed using a nutritional analysis database. Rate of UTIs after EF and urine pH after consumption of acidic foods was compared between urine pH groups. Our hypothesis was that low urinary pH protects against RUTIs. ResultsOf 37/69 patients who underwent EF with long median follow-up duration (4-6 years), no difference was found among the groups for UTI frequency, rate, and culture characteristics. There was a no significant difference in the mean amount of acidic foods eaten and the urine pH after each meal as well as in total. ConclusionsDuring long-term follow-up, no association was found between urine pH groups and acidic food intake, and rates of UTIs after EF, possibly because of no link between urine pH and UTIs or EF already provokes an important reduction in rates of UTIs.

SAPHO syndrome treated with minodronic acid hydrate, facet rhizotomy and denosumab: a case report

SAPHO syndrome treated with minodronic acid hydrate, facet rhizotomy and denosumab: a case report

Relationship between Surpoint Tag Index, a Radiofrequency Ablation lesion quality indicator, and Atrial wall thickness in Cavotricuspid isthmus Ablations exhibiting bidirectional block.

BackgroundAn RFA lesion quality indicator, Surpoint Tag Index® (TI) incorporates key factors: power, time, and contact force, impacting lesion quality. TI accurately estimates lesion depth in animal studies. However, the relationship between TI and in‐vivo atrial wall thickness in patients exhibiting bidirectional block remains unknown.ObjectiveTo describe the relationship between atrial wall thickness and TI in CTI exhibiting bidirectional block.MethodsData from 492 RFA lesions from 25 patients undergoing PVI and CTI ablations in SR with point‐by‐point RF lesions (<45 W) utilizing a Thermocool Smarttouch® SF ablation catheter and CARTO‐3 mapping were retrospectively analyzed. Operators were blinded to TI data and CTI thickness. CTI thickness was obtained using ICE images on Cartosound pre‐ablation. Durable lesions were defined as part of a lesion set exhibiting bidirectional block of >30 min.ResultsIn lesions exhibiting bidirectional block, the thinnest (1–2 mm; 5% lesions) and thickest (8–10 mm; 6% lesions) portions of the CTI correlated with the lowest (429 ± 75) and highest (516 ± 64) TI. The bulk of thickness (2–6 mm; 80%) correlated with a TI of 455 ± 72 (p = 0.001). There was a weak but positive correlation between TI and CTI thickness (r = 0.2; p ≤ 0.01). Examined in sectors, the anterior 1/3rd CTI was the thickest (4.8 ± 1.9 mm) but correlated with a similar TI value (479 ± 75 vs. 471 ± 70; p = 0.34) as the thinner middle 1/3rd (3.8 ± 1.7 mm; p ≤ 0.0001).ConclusionA mean TI value of 455 correlates with bidirectional block across the bulk of CTI with lower and higher values needed for the thinner and thicker portions, respectively. Tissue composition, aside from wall thickness, influences TI values for the creation of the bidirectional block.

Polarization-sensitive optical coherence tomography monitoring of percutaneous radiofrequency ablation in left atrium of living swine

Radiofrequency ablation (RFA) is commonly used to treat atrial fibrillation (AF). However, the outcome is often compromised due to the lack of direct real-time feedback to assess lesion transmurality. In this work, we evaluated the ability of polarization-sensitive optical coherence tomography (PSOCT) to measure cardiac wall thickness and assess RF lesion transmurality during left atrium (LA) RFA procedures. Quantitative transmural lesion criteria using PSOCT images were determined ex vivo using an integrated PSOCT-RFA catheter and fresh swine hearts. LA wall thickness of living swine was measured with PSOCT and validated with a micrometer after harvesting the heart. A total of 38 point lesions were created in the LA of 5 living swine with the integrated PSOCT-RFA catheter using standard clinical RFA procedures. For all lesions with analyzable PSOCT images, lesion transmurality was assessed with a sensitivity of 89% (17 of 19 tested positive) and a specificity of 100% (5 of 5 tested negative) using the quantitative transmural criteria. This is the first report of using PSOCT to assess LA RFA lesion transmurality in vivo. The results indicate that PSOCT may potentially provide direct real-time feedback for LA wall thickness and lesion transmurality.

MP25-13 EXPERIENCE WITH COMPLETE TRIGONAL ELECTROFULGURATION FOR WOMEN WITH RECURRENT URINARY TRACT INFECTIONS: TWO YEARS FOLLOW-UP

You have accessJournal of UrologyInfections/Inflammation/Cystic Disease of the Genitourinary Tract: Kidney & Bladder I (MP25)1 Sep 2021MP25-13 EXPERIENCE WITH COMPLETE TRIGONAL ELECTROFULGURATION FOR WOMEN WITH RECURRENT URINARY TRACT INFECTIONS: TWO YEARS FOLLOW-UP Leopoldo Ribeiro-Filho, Felipe Hirasaki, Eduardo Miranda, Matheus Siqueira, Cristiano Gomes, Miguel Srougi, and William Nahas Leopoldo Ribeiro-FilhoLeopoldo Ribeiro-Filho More articles by this author , Felipe HirasakiFelipe Hirasaki More articles by this author , Eduardo MirandaEduardo Miranda More articles by this author , Matheus SiqueiraMatheus Siqueira More articles by this author , Cristiano GomesCristiano Gomes More articles by this author , Miguel SrougiMiguel Srougi More articles by this author , and William NahasWilliam Nahas More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002022.13AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Recurrent urinary tract infections (RUTI) have a negative impact on quality of life, contribute to antimicrobial resistance and have a significant economic burden. Long-term antibiotic therapy is the main treatment alternative but is often ineffective or poorly tolerated. In selected women, electrofulguration (EF) of trigonal lesions has been shown to reduce UTI episodes. In this study we evaluated the efficacy of complete trigonal EF for women with RUTI. METHODS: Between August 2006 and December 2017, 73 women with RUTI defined as three or more episodes of UTI per year were included in the study and completed at least two years of follow-up. All had undergone proper evaluation to exclude common causes of RUTI and all had squamous metaplasia and/or inflammatory lesions of the trigone or bladder neck. All had failed multiple antibiotic courses and were offered trigonal electrofulguration. Under anesthesia, endoscopic electrofulguration of the entire trigonal and bladder neck mucosa was performed using a roller ball. Biopsies were obtained prior to fulguration for histopathology analysis and in situ hybridization for Human Papiloma Virus (HPV). Patients were maintained on continuous bladder irrigation for a few hours and discharged home with no indwelling catheter. We evaluated the rate of UTIs during the initial two years of followup after fulguration based on symptoms and a positive urine culture. RESULTS: The median age was 64 years (range 17–76) and the median follow-up time after EF was 4.2 years (range 2.5 to 14 years). The procedure was well tolerated by all patients. Adverse events, most frequently disuria were mild and transient. In 24/76 (33%) patients bladder lesions in areas other than the trigone and bladder neck were also fulgurated. Histologically, squamous metaplasia (SM) was found in 31 (42%) patients and chronic erosive trigonitis (ET) in 42 (58%). HPV in situ hybridization was positive in 4/31 (13%) patients in the SM group and none in the ET group. Overall, 70/76 (96%) patients remained free of UTI episodes during the first year of follow-up, including 29/31 (94%) in the SM group and 41/42 (98%) in the ET group. At 2 years of follow-up, 15/31 (48%) in the SM group remained infection-free vs 27/42 (64%) in the ET group .UTIs were typically sparse, mild and caused by multisensitive bacteria. CONCLUSIONS: Complete trigonal and bladder neck mucosal fulguration promoted a significant reduction of UTI episodes during the first two years of follow-up. Prospective controlled studies are needed to determine the role of EF in women with RUTI. Source of Funding: none © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e458-e458 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Leopoldo Ribeiro-Filho More articles by this author Felipe Hirasaki More articles by this author Eduardo Miranda More articles by this author Matheus Siqueira More articles by this author Cristiano Gomes More articles by this author Miguel Srougi More articles by this author William Nahas More articles by this author Expand All Advertisement Loading ...

B-PO03-106 ASSOCIATION BETWEEN ADENOSINE USE AND ATRIAL FIBRILLATION RECURRENCE AFTER PULMONARY VEIN ISOLATION USING HIGH POWER SHORT DURATION ABLATION IN PATIENTS WITH ATRIAL FIBRILLATION

There is conflicting literature with regards to the effectiveness of adenosine in assessing PVI and long-term outcomes. Effectiveness of adenosine in the setting of HPSD is unknown. To study the association between adenosine use to assess pulmonary vein isolation (PVI) and long-term outcomes in patients who underwent atrial fibrillation (AF) ablation using high power short duration (HPSD) radiofrequency ablation technique. In this retrospective cohort analysis, case records of 215 consecutive patients with paroxysmal AF who underwent ablation at Wake Forest University, Baptist hospital between January 2018 - May 2020 were assessed. Five operators performed all the ablations using HPSD technique (50 watts RF lesions applied 5-8 secs in the posterior wall and 10 secs in the anterior wall). All study patients uniformly received PVI. Further, 81% (174/215 patients) received adenosine to assess PV reconnection and 19% (41/215 patients) did not receive adenosine to assess PV reconnection. Adenosine administration was per the discretion of the operator. Of the 215 study patients, 140/215 patients (65%) were men. Mean age was 66 years. At 1year follow-up, 14/41 (34%) had recurrence of AF in the no-adenosine group, whereas 53/174 (30%) had recurrence in the adenosine group (P = 0.65). Adenosine use to assess PV reconnection had similar odds of AF recurrence at 1-year follow-up [(unadjusted OR: 0.85, 95% CI: 0.41 - 1.74, P = 0.65), (fully adjusted OR: 0.82, 95% CI: 0.40 - 1.73, P = 0.61)]. Adenosine use to assess PV reconnection did not decrease AF recurrence at 1-year follow-up in patients undergoing PVI using HPSD technique. Larger sample randomized investigations are needed to confirm our findings.

Focused Electric Field Ablation: A Novel Technology to Increase Ablation Lesion Depth With Improved Safety

Background: RF ablation is limited in its ability to deliver deep lesions, as most of the energy delivered to the tissue is dissipated in the first few millimeters from the catheter tip. Focused Electric Field (FEF) is a novel technology with the potential to ablate much deeper than current RF catheters. This work is the first proof of concept of FEF technology. Objective: To introduce FEF technology and demonstrate its feasibility as an ablation tool. Methods: We constructed an FEF catheter with a hemispherical concave tip. We performed ablation ex vivo in porcine hearts and examined ablation characteristics using both tissue sectioning and real-time thermal imaging. Results: RF lesions were 9.1{plus minus}1.0mm wide by 6.1{plus minus}1.1mm deep with ablation using an irrigated tip catheter (Thermocool SF). In contrast, lesions created using FEF ablation were 16.1{plus minus}2mm wide and 15.2{plus minus}1.1mm deep. Steam pops were much less frequent with FEF technology (6.7% incidence for FEF vs. 38% with Thermocool). Thermal imaging demonstrated that in contrast to an irrigated tip RF catheter, the FEF catheter generated a uniform temperature profile down to a maximum depth exceeding 15mm. Conclusion: This study is the first proof of concept of FEF technology. Using a novel concave catheter tip design the electric field remains confined to a narrow tissue region thus avoiding the rapid fall off in energy delivery from the tissue surface that is inherent to current RF technology. FEF ablation has the potential to allow significantly deeper ablation than current RF catheter technologies with an improved safety margin.

Comparison of the lesion formation and safety in ex vivo porcine heart study: Using ThermoCool SmartTouch and ThermoCool SmartTouch-SF catheters.

The study was performed to compare the efficacy and safety during radiofrequency ablation (RFA) using ThermoCool SmartTouch (ST) and ThermoCool SmartTouch-SF (STSF) catheters in the porcine heart. RFA was performed on the porcine myocardium by using two irrigated ablation catheters. Three groups were divided based on the different contact forces (CFs): low contact force (LCF) (1-3 g), medium contact force (MCF) (5-10 g), and high contact force (HCF) (15-20 g). In each group, RFA was delivered at four power settings of 30, 40, 50, 60 W. At each power, RFA was applied to reach the target ablation index (AI) of 350, 450, and 500. Altogether, 360 RF lesions were created by using 72 ablation conditions. AI value was positively correlated with lesion size using ST and STSF catheters. At a fixed power, lesion dimensions significantly smaller in the LCF group, whereas did not differ between MCF and HCF groups. Furthermore, at a fixed CF, lesion dimensions increased with power set at 40 W compared with 30 W but decreased with high-power RF energy (50 and 60 W). Although the average lesion surface diameter and the maximum diameter was increased using the STSF catheter, there were no significant differences in LV between the two catheters. The steam pop provoked more frequently using ST catheter and showed a negative correlation with CF and positive correlation with high-power energy. The STSF catheter is safer and equally effective in lesion formation compared with the ST catheter. LV was increased along with the early increase of CF and power, whereas a further increase of CF and power significantly reduces the lesion size.

Nonhomogeneous force application during typical flutter ablation explains local difficulties in lesion creation

Introduction – The current scientific literature suggests similar or even better catheter contact on caval regions of the cavo-tricuspid isthmus (CTI) compared to the more medial or annular part. Yet CTI ablation can be challenging owing to instability at the inferior vena cava (IVC) edge. No study specifically addressed the issue of catheter-tissue contact on caval/mid/annular regions of the CTI. Methods – Twenty-seven patients (22 men, 67±12 years) underwent typical atrial flutter ablation with a contact force (CF) sensing catheter (Tacticath 75, Abott) and were prospectively included. Operators aimed at optimizing CF for all RF pulses. The product of CF, time (force-time integral; FTI) and delivered power (FTPI) has been proposed as an estimate of lesion size. In a subset of 8 consecutive pts, electrograms (EGM) of all RF lesions were analyzed. Annular CTI was defined as sites showing both atrial and ventricular near-field bipolar EGM. Mid CTI sites had only atrial near field bipolar EGM on both distal and proximal dipoles (or distal only in case of superior-to-inferior approach). Caval sites had near-field bipolar EGM only in distal dipole, while the proximal one was inferiorly located. Results – Complete persistent (at 30 min) CTI block was obtained in all patients. A steerable sheath was used in 12 pts (44%). Procedure duration was 93±30 min, RF delivery time 10±6 min, fluoroscopy time 14±8 min. Mean CF was 15.8±5.9 g. CF was significantly lower (11.1±9.7 g) at the caval CTI than at mid CTI (19.9±11.8 g) and annular CTI (20±12.2 g; p=0.001). CF and FTI were higher during sinus rhythm than during Fl (23.2±15.3 vs 18.5±15.4 g, p=0.04 and 677±432 vs 532±357 gs, p=0.03). Use of a sheath improved mean CF (24.4±12.5 vs 18.4±14.9 g, p=0.01) but this was not significant at caval sites (17.5±11.4 vs 12.6±10.7 g, p=0.31). Conclusion – Applied forces are significantly lower at the IVC edge during CTI ablation. This supports the use of a steerable sheath in challenging cases.

The challenge of optimising ablation lesions in catheter ablation of ventricular tachycardia.

Radiofrequency catheter ablation has become an established treatment for ventricular tachycardia. The exponential increase in procedures has provided further insights into mechanisms causing arrhythmias and identification of ablation targets with the development of new mapping strategies. Since the definition of criteria to identify myocardial dense scar, borderzone and normal myocardium, and the description of isolated late potentials, local abnormal ventricular activity and decrementing evoked potential mapping, substrate‐guided ablation has progressively become the method of choice to guide procedures. Accordingly, a wide range of ablation strategies have been developed from scar homogenization to scar dechanneling or core isolation using increasingly complex and precise tools such as multipolar or omnipolar mapping catheters. Despite these advances long‐term success rates for VT ablation have remained static and lower in nonischemic than ischemic heart disease because of the more patchy distribution of myocardial scar. Ablation aims to deliver an irreversible loss of cellular excitability by myocardial heating to a temperatures exceeding 50°C. Many indicators of ablation efficacy have been developed such as contact force, impedance drop, force‐time integral and ablation index, mostly validated in atrial fibrillation ablation. In ventricular procedures there is limited data and ablation lesion parameters have been scarcely investigated. Since VT arrhythmia recurrence can be related to inadequate RF lesion formation, it seems reasonable to establish robust markers of ablation efficacy.

Utility of novel Omnipolar activation mapping for the detection of ventricular premature contraction origin

Abstract Background Bipolar electrograms are significantly influenced by direction of the propagating wavefront in relation to the recording bipole. Omnipolar voltage mapping may be superior to standard bipolar mapping since it obtains maximum voltage of all possible bipolar electrode orientations without the need for catheter rotation. Therefore, omnipolar maps can provide voltage maps with larger voltages as well as better defined boundaries. Purpose Whether omnipolar activation maps also describe better activation maps versus traditional bipolar maps during ventricular premature contraction (VPC) catheter ablation is unclear. Methods A high-density mapping catheter was advanced to the ventricular outflow tract and a high-resolution activation map was created. Each electrode along and across the splines of the catheter are 4mm apart. Bipoles were calculated along (MAP 2), across (MAP 3) and bidirectional (MAP 4) the splines while omnipoles (MAP 1) were derived from a right triangle clique. Within a square area, four omnipolar and two bipolar values along, across and bidirectional values were defined. Results Though the earliest activation site was vague by along and across maps (arrow), white color became evident by bidirectional map, and the VPC origin became distinct with omnipolar mapping. RF lesions were given via an open-irrigated ablation catheter targeting a lesion size index 5.0. The VPC was eliminated by radiofrequency ablation. Conclusion Omnipolar activation mapping may be more accurate than traditional bipolar mapping during ventricular premature contraction (VPC) catheter ablation. Figure 1 Funding Acknowledgement Type of funding source: None

Vesicular Cystitis: A Chronic Cystitis Variant Often Unresponsive to Antibiotics and Electrofulguration

Objective: The aim of the study was to report on the presentation and outcomes of vesicular cystitis (VC), a chronic cystitis exhibiting translucent bladder mucosal vesicles, among women with antibiotic-refractory recurrent urinary tract infections (RUTIs). Methods: An analysis of our Institutional Review Board-approved series on antibiotic-refractory RUTIs was performed, selecting for documented VC lesions on cystoscopy. All patients had RUTIs defined as ≥3 urinary tract infections/year with positive urine culture. All patients were extensively treated with antibiotics with no resolution of RUTIs and were offered electrofulguration (EF) of VC lesions under anesthesia as a last resort. All patients had a 6-month post-EF office cystoscopy documenting persistence or resolution of the lesions, and a clinical outcome assessment based on RUTI frequency. Results: Of 482 patients, 18 (3.7%) treated during 2011–2017 met the study criteria. VC was most commonly found over the dome/anterior wall (7/18, 38%) and as pancystitis (7/18, 38%). There was often concomitant cystitis cystica of the trigone (8/18, 44%). At post-EF cystoscopy, persistence of VC was noted in 10/18 (56%) patients; 6/18 (33%) underwent repeat EF and an additional 3/18 (17%) were retreated due to new lesions after initial resolution. Two (11%) patients required simple cystectomy and urinary diversion due to RUTIs refractory to all interventions. Within a median follow-up of 2.8 years after EF, clinical cure was observed in 5/18 (28%), improvement in 10/18 (56%), and failure in 3/18 (17%) patients. Conclusions: Among women with antibiotic-refractory RUTIs, VC is an infrequent and persistent form of cystitis with a predilection for non-trigonal bladder surfaces, whose management is challenging.

Impact of Variableorientation and Flow Rates on Radiofrequency Ablation Lesions Created by Externally Irrigated Catheters: An Ex-Vivo Study.

The impact of variability in irrigation rates and catheter orientation on radiofrequency ablation (RF) lesion creation has not been studied systematically for the uniformly irrigated 56-pore (56P) catheter. This study aimed to analyze the impact of irrigation flow rates (IFRs) and catheter orientation (CO) settings on RF lesions sizes produced by a 56P irrigation catheter in a power-controlled mode using an ex-vivo model. RF lesions were created in strips of chicken muscle in a saline bath heated to 37°C with 56P and 6P catheters using low flow rate (LFR) at 2 cc/min and standard flow (SFR) irrigation rates at 8 cc/min for 56P and 17 cc/min for 6P with horizontal (HO) and vertical (VO) catheter orientations. Ablation power of 20W was delivered for 30 seconds with a mean contact force of 10 g. Sixty RF lesions were analyzed. For the 56P catheter, in contrast to the 6P catheter lesion geometry was independent of CO and IFR in our model. Although 6P catheter had slightly deeper lesions, the overall lesion volumes were similar for 6P and 56P catheters. CO and IFR appeared to have minimal impact on lesion volume creation with 56P catheter. In head-to-head comparison the 6P and 56P irrigated catheters performed similarly.