Clinical outcomes of radiofrequency catheter ablation of ventricular tachycardia in patients with hypertrophic cardiomyopathy.

BACKGROUND: Monomorphic ventricular tachycardia (VT) is rare in patients with hypertrophic cardiomyopathy (HCM), management of which is challenging. Limited data exists on the utility of catheter ablation for the treatment of VT in this population. OBJECTIVES: We aimed to assess clinical outcomes of catheter ablation for VT in HCM patients. METHODS: A systematic search, without language restriction, using PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov was performed. The meta-analysis was performed using a meta-package for R version 4.0/RStudio version 1.2 and Freeman Tukey double arcsine method to establish the variance of raw proportions. Outcomes measured included (1) acute procedure success (defined as noninducible for clinical VT), (2) freedom from VT at follow-up, (3) mortality. RESULTS: This systematic review of six studies (three from the United States and three from Japan) incorporated a total of 68 drug-refractory HCM patients who underwent VT radiofrequency catheter ablation (mean age 57.6 ± 13.3 years, mean LVEF 45.8 ± 15.4%, 85% men, maximum septal wall thickness 17.4 ± 4.6 mm, and 32.3% with an apical aneurysm). Acute procedural success was achieved in 84.5% patients (95% confidence interval [CI]: 70.6%-95.2%) with 27.9% patients had recurrent VT requiring multiple ablations (median 1, IQR 1-3). During the follow-up period (18.3 ± 11.7 months), the pooled incidence of freedom from recurrent VT after index procedure was 70.2% (95% CI: 51.9%-86.2%), while after the last ablation was 82.8% (95% CI: 57%-99.2%). There were two deaths during follow-up, one from heart failure and one from SCD 0.8% (95% CI: 0%-5.8%). CONCLUSION: The results of our pooled analysis demonstrated that catheter ablation for VT in HCM patients was associated with high acute procedural success, and reduced VT recurrence-findings comparable to previously published reports in other disease substrates.

Adverse events associated with amplatzer left atrial appendage occlusion delivery system: A Food and Drug Administration MAUDE database study.

BACKGROUND: Dual occlusive closure mechanism (disc and lobe type), Amulet device (Abbott; a second-generation device that has replaced Amplatzer Cardiac Plug) was approved by the Food and Drug Administration (FDA) in August 2021 for percutaneous left atrial appendage occlusion (LAAO). However, real-world safety data on the delivery system (Amplatzer Cardiac Plug and Amplatzer Amulet device) are lacking. OBJECTIVE: We sought to assess the type of adverse events associated with the Amplatzer LAAO delivery system using the FDA Manufacturer and User Facility Device Experience (MAUDE) database. METHODS: A MAUDE database search was conducted on March 31, 2023, for reports received between February 2013 and March 2023 to capture all adverse events. RESULTS: A total of 59 adverse events were reported, of which 58 were sheath-related events, and one was a wire-related event. The most commonly encountered issue was air embolism (19%, 11 events), followed by sheath thrombosis (13.8%, eight events, two of which were also associated with device thrombosis), kinked sheath (10.3%, six events), and sheath deformation (8.6%, five events). Patient-related adverse events included pericardial effusion requiring pericardiocentesis (22.4%, 13 events), vascular complications (20.7%, 12 events), and device dislodgement (5.2%, three events). CONCLUSION: LAAO-related adverse events are increasingly being reported using the Amplatzer LAAO delivery sheath. It is anticipated that improvements in device technology, the advent of steerable sheaths, and operator experience will minimize these complications.

Adverse events associated with AveirTM VR leadless pacemaker: A Food and Drug Administration MAUDE database study.

BACKGROUND: Leadless pacemaker (LP) offers an innovative approach for treating bradyarrhythmia, thus avoiding pacemaker pocket and lead-related complications. The Food and Drug Administration (FDA) has recently approved the Aveir™ leadless pacing system (screw-in type LP). METHODS: We queried the FDA MAUDE database to study the safety profile and assess the types of complications with this relatively novel device technology. A MAUDE database search was conducted on January 20, 2023, for reports received post-FDA approval to capture all adverse events. RESULTS: A total of 98 medical device report were reported for Aveir™ LP. After excluding duplicate, programmer-related, or introducer-sheath-related entries (n = 34), 64 entries were included. The most commonly encountered problem was high threshold/noncapture (28.1%, 18 events), followed by stretched helix (17.2%, 11 events) and device dislodgement (15.6%, ten events-5 intraprocedural, while 5 in the postoperative Day 1). Other reported events included high impedance (14.1%, nine events), sensing issues (12.5%, eight events), bent/broken helix (7.8%, five events), premature separation (4.7%, three events), interrogation problem (3.1%, two events), low impedance (3.1%, two events), premature battery depletion (1.6%, one event) and inadvertent MRI mode switch (1.6%, one event) and miscellaneous (15.6%, n = 10). There were eight serious patient injury events-pericardial effusion requiring pericardiocentesis (7.8%, five events) due to cardiac perforation that resulted in two deaths (3.1%) followed by sustained ventricular arrhythmias (4.6%, n = 3). CONCLUSION: In our study assessing the real-world safety profile of the Aveir™ LP, serious adverse events have been reported-life-threatening ventricular arrhythmias, pericardial effusion, device explantation/reimplantation, and death.

Intracardiac echocardiography from coronary sinus.

Intracardiac echocardiography (ICE) has become an essential tool and is an integral part of percutaneous interventional and electrophysiology (EP) procedures. Intracardiac echocardiography offers real-time, high-quality, near-field evaluation of cardiac anatomy. Standard ICE imaging includes placing the catheter in the right atrium (RA), right ventricle (RV), or left atrium (LA, via the transeptal approach). Coronary sinus echocardiography (CSE) is another alternative, where the ICE catheter is positioned in the coronary sinus (CS). This approach offers better catheter stability and allows operators to visualize cardiac structure with particularly excellent views of the LA, LAA, left ventricle (LV), and mitral annulus. Additionally, CSE is an attractive alternative in cases with unfavorable interatrial septum or fossa ovalis anatomical features that could lead to difficulty advancing ICE catheter in left atrium. In this article focusing on CSE, we provide illustration-based guidance to help operators identify critical cardiac structures from CSE.

Periprocedural outcomes of protamine administration after catheter ablation of atrial fibrillation.

BACKGROUND: Perioperative anticoagulation management with uninterrupted or minimally interrupted anticoagulation during atrial fibrillation (AF) ablation is thought to be critical to minimize thromboembolic complications. Protamine is often administered to neutralize the effects of heparin and expedite vascular hemostasis post-procedure. OBJECTIVE: We performed a systematic review and meta-analysis to determine the effectiveness of protamine to expedite vascular hemostasis and ambulation in patients undergoing AF ablation. METHODS: Electronic searches on PubMed, The Cochrane Library, EMBASE, EBSCO, Web of Science, and CINAHL databases from the inception through August 7, 2021, were performed. The primary outcomes included-time to hemostasis (minutes) and time to ambulation (minutes). The secondary outcomes included - any vascular complications (excluding minor hematoma), minor hematoma, or cerebrovascular accidents (CVA). RESULTS: A total of 5 eligible studies (3 retrospective cohort studies and two randomized trials) consisting of 1012 patients (515 patients received protamine group and 497 patients did not receive protamine group) were included in the meta-analysis. There was a significant reduction in time to ambulation [weighted mean difference (WMD) -176.6 minutes, 95% Confidence interval (CI) -266.9 to -86.3; p < 0.01] and time to hemostasis (WMD -13.72 minutes, 95% CI -22 to -5.4, p < 0.01) in the protamine group compared to the contrary. At a follow-up up to 3 months, there was no statistical difference between the two groups with regards to vascular complications (2.9% vs. 7.4%; Risk ratio (RR) 0.46 95% CI 0.17 to 1.24; p = 0.12), minor hematoma (2.1% vs. 5.8%; RR 0.43, 95% CI 0.16 to 1.2; p = 0.11) or CVA (0 vs. 0.3%; RR 0.62, 95% CI 0.08 to 4.98; p = 0.65). CONCLUSION: Protamine administration was associated with reduced time to ambulation (176 minutes reduction) and time to hemostasis (13 minutes reduction) without an increase in any adverse events.

Electromagnetic interference induced ventricular tachycardia in left ventricular assist device.

Left ventricular assist devices (LVAD) have been increasingly utilized end-stage heart failure despite guidelinedirected medical therapy (due to limited organ availability) as a bridge to transplant or destination therapy, with improved overall survival.Majority of patients undergoing LVAD implantation have pre-existing implantable cardioverter-defibrillator (ICD) in-situ.We present a case of device-device interaction resulting in EMI inducing recurrent inappropriate device therapies inducing ventricular arrhythmia followed by the inappropriate triggering of noise reversion mode, thereby inhibiting device therapies.With the increase in number of end-stage heart failure patients with ICDs in situ (and limited organ availability) undergoing LVAD implantation, it is imperative to recognize potential device-device interactions to avoid unwarranted invasive interventions.

Surgical left atrial appendage occlusion in patients with left ventricular assist device.

BACKGROUND: Thromboembolic (TE) events are among the most common and devastating adverse events in patients with continuous-flow left ventricular assist device (cf-LVAD). Given the high burden of AF among cf-LVAD patients, we sought to evaluate the effect of concomitant surgical LAAO in patients receiving cf-LVAD. METHODS: A systematic search using electronic databases was performed using the keywords: "left atrial appendage occlusion" and "left ventricular assist device." Statistical analysis was performed using metapackage for R version 4.0 and Rstudio version 1.2. Mantel-Haenszel risk ratio (RR) random-effects model was used to summarize data between two groups. The primary outcomes included: (a) stroke; (b) LVAD pump thrombosis; (c) all-cause mortality RESULTS: Three studies with a total of 305 patients (LAAO = 68 and No-LAAO = 237) were included in the analysis. HeartMate II (39%) and Heartware (27.5%) were the two most common cf-LVADs utilized, while only 5% received HeartMate III. At a mean follow up of 1.47 years, LAAO group had a lower risk of stroke (8.8% vs. 15.2%, RR 0.64; 95% CI 0.28-1.49), LVAD pump thrombosis (1.5% vs. 3.8%, RR 0.28; 95% CI 0.05-1.55) and all-cause mortality (5.9% vs. 20.2%, RR 0.69; 95% CI 0.19-2.52) when compared with no-LAAO group, but the difference did not reach statistical significance. CONCLUSION: Concomitant surgical LAAO at the time of cf-LVAD implantation demonstrated a trend toward positive outcomes and was not associated with adverse outcomes during the follow-up period, though the results were not statistically significant.

Early modified primary closure for treatment of cardiac implantable electronic device pocket infections.

BACKGROUND: Guidance for wound management of the vacated generator pocket in cardiac implantable electronic device (CIED) pocket infections after removal of all hardware and tissue debridement is limited. The typical surgical technique for management of a purulent wound is to allow healing by secondary intention. An alternative approach uses negative pressure wound therapy with or without delayed primary closure. While effective in managing infection, these approaches increase hospital length of stay and costs. We present our experience with a third option: modified early primary wound closure over a suction device. METHODS: All patients with CIED pocket infections who presented to our institution between September 2018 and October 2020 underwent extraction of hardware and modified primary wound closure over a negative pressure Jackson-Pratt drain. Length of hospital and postoperative stay, complications, and recurrent infections were recorded. RESULTS: During the study period, 14 patients underwent modified primary wound closure for CIED pocket infections. Mean length of hospital stay was 6.64 days ± 4.01 days (standard deviation [SD]). Mean postoperative length of stay was 3.92 ± 2.21 days (SD). Two patients (both on intravenous heparin for mechanical valve prostheses) required re-exploration for bleeding. No patients developed recurrent infection at a mean follow up of 363 ± 245 days (SD). CONCLUSION: Based on our experience, early modified primary wound closure for CIED pocket infections appears to be safe and allows for prompt discharge with no observed re-infections.

Trends, management and outcomes of acute myocardial infarction in chronic liver disease.

AIMS: There are limited data on the management and outcomes of chronic liver disease (CLD) patients presenting with acute myocardial infarction (AMI), particularly according to the subtype of CLD. METHODS: Using the Nationwide Inpatient Sample (2004-2015), we examined outcomes of AMI patients stratified by severity and sub-types of CLD. Multivariable logistic regression was performed to assess the adjusted odds ratios (aOR) of receipt of invasive management and adverse outcomes in CLD groups compared with no-CLD. RESULTS: Of 7 024 723 AMI admissions, 54 283 (0.8%) had a CLD diagnosis. CLD patients were less likely to undergo coronary angiography (CA) and percutaneous coronary intervention (PCI) (aOR 0.62, 95%CI 0.60-0.63 and 0.59, 95%CI 0.58-0.60, respectively), and had increased odds of adverse outcomes including major adverse cardiovascular and cerebrovascular events (1.19, 95%CI 1.15-1.23), mortality (1.30, 95%CI 1.25-1.34) and major bleeding (1.74, 95%CI 1.67-1.81). In comparison to the non-severe CLD sub-groups, patients with all forms of severe CLD had the lower utilization of CA and PCI (P < .05). Among severe CLD patients, those with alcohol-related liver disease (ALD) had the lowest utilization of CA and PCI; patients with ALD and other CLD (OCLD) had more adverse outcomes than the viral hepatitis sub-group (P < .05). CONCLUSIONS: CLD patients presenting with AMI are less likely to receive invasive management and are associated with worse clinical outcomes. Further differences are observed depending on the type as well as severity of CLD, with the worst management and clinical outcomes observed in those with severe ALD and OCLD.

Prevalence and in-hospital outcomes of patients with malignancies undergoing de novo cardiac electronic device implantation in the USA.

AIMS: To study the outcomes of cancer patients undergoing cardiac implantable electronic device (CIED) implantation. METHODS AND RESULTS: De novo CIED implantations (2004-15; n = 2 670 590) from the National Inpatient Sample were analysed for characteristics and in-hospital outcomes, stratified by presence of cancer (no cancer, historical and current cancers) and further by current cancer type (haematological, lung, breast, colon, and prostate). Current and historical cancer prevalence has increased from 3.3% to 7.8%, and 5.8% to 7.8%, respectively, between 2004 and 2015. Current cancer was associated with increased adjusted odds ratio (OR) of major adverse cardiovascular events (MACE) [composite of all-cause mortality, thoracic and cardiac complications, and device-related infection; OR 1.26, 95% confidence interval (CI) 1.23-1.30], all-cause mortality (OR 1.43, 95% CI 1.35-1.50), major bleeding (OR 1.38, 95% CI 1.32-1.44), and thoracic complications (OR 1.39, 95% CI 1.35-1.43). Differences in outcomes were observed according to cancer type, with significantly worse MACE, mortality and thoracic complications with lung and haematological malignancies, and increased major bleeding in colon and prostate malignancies. The risk of complications was also different according to CIED subtype. CONCLUSION: The prevalence of cancer patients amongst those undergoing CIED implantation has significantly increased over 12 years. Overall, current cancers are associated with increased mortality and worse outcomes, especially in patients with lung, haematological, and colon malignancies whereas there was no evidence that historical cancer had a negative impact on outcomes.

Is Statin Use Associated With Tendon Rupture? A Population-Based Retrospective Cohort Analysis.

Previous case reports and small studies have suggested that 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (HMG-CoA-Is) may increase the risk of tendon rupture. We conducted a population-based retrospective cohort evaluation to better assess this relationship. From approximately 800,000 enrollees of a private insurance database, those who were aged ≤64 years with at least 1 year of continuous enrollment were selected. Exposure was defined as initiation of HMG-CoA-I after the beginning of the study period. Each exposed person was matched with 2 controls of similar age and gender. Baseline characteristics, including known risk factors for tendon rupture, were compared between exposed and control cohorts with fidelity to the study's matched design. After adjusting for differences in follow-up and baseline characteristics, incidence rate ratios for tendon rupture was assessed in HMG-CoA-I users and nonusers. A total of 34,749 exposed patients were matched with 69,498 controls. There was no difference in the occurrence of tendon ruptures in HMG-CoA-I users versus nonusers. The results remained unchanged after adjustment for age and gender. In conclusion, this population-based retrospective cohort evaluation suggests that use of HMG-CoA-Is as a group are not associated with tendon rupture.

New-generation electronic appliances and cardiac implantable electronic devices: a systematic literature review of mechanisms and in vivo studies.

INTRODUCTION: Cardiac implantable electronic device (CIED) functions are susceptible to electromagnetic interference (EMI) from electromagnetic fields (EMF). Data on EMI risks from new-generation electronic appliances (EA) are limited. OBJECTIVE: We performed a systematic literature review on the mechanisms of EMI, current evidence, and recently published trials evaluating the effect of EMF on CIEDs from electric vehicles (EV), smartphone, and smartwatch technology and summarize its safety data. METHODS: Electronic databases, including PubMed and EMBASE, were searched for in vivo studies evaluating EMF strength and incidence between CIEDs and commercial EVs, new-generation smartphones, and new-generation smartwatches. RESULTS: A total of ten studies (three on EVs, five on smartphones, one on smartphones, one on smartphones and smartwatches) were included in our systematic review. There was no report of EMI incidence associated with EVs or smartwatches. Magnet-containing smartphones (iPhone 12) can cause EMI when placed directly over CIEDs - thereby triggering the magnet mode; otherwise, no report of EMI was observed with other positions or smartphone models. CONCLUSION: Current evidence suggests CIED recipients are safe from general interaction with EVs/HEVs, smartphones, and smartwatches. Strictly, results may only be applied to commercial brands or models tested in the published studies. There is limited data on EMI risk from EVs wireless charging and smartphones with MagSafe technology.

Antiphospholipid antibody-associated non-infective mitral valve endocarditis successfully treated with medical therapy.

Non-bacterial endocarditis lesions associated with antiphospholipid antibodies (aPLs) in the absence of other criteria for antiphospholipid syndrome or systemic lupus erythematosus is termed an aPL-associated cardiac valve disease. Evidence regarding the management of this condition is sparse. A rare case is described of a 20-year-old female who presented with an incidental finding of 'vegetations on a heart valve'. Echocardiography revealed mitral valve leaflet thickening and echodensities with moderate mitral regurgitation. She had an elevated partial thromboplastin time that did not correct with a mixing study, and elevated levels of antiocardiolipin antibodies. Hence, a diagnosis of aPL-associated cardiac valve disease was made, and the patient commenced on warfarin, hydroxychloroquine, and a short course of oral prednisone. At one year after diagnosis the patient remained symptom-free, and follow up echocardiography revealed resolution of the vegetations with minimal mitral regurgitation. Further evidence is needed to guide the therapy of this rare condition.

Management of an Inadvertently Placed Transarterial Pacemaker Lead in the Left Ventricle: A Step-by-step Approach.

Inadvertent lead misplacement in the left ventricle can lead to thromboembolic events, valvular damage, and endocarditis. We present a case of an inadvertently placed transarterial pacemaker lead in the left ventricle in a patient who underwent percutaneous lead removal. After a multidisciplinary team discussion involving cardiac electrophysiology and interventional cardiology as well as a discussion of treatment options with the patient, it was decided to proceed with pacemaker lead removal with the Sentinel™ Cerebral Protection System (Boston Scientific, Marlborough, MA, USA) to prevent thromboembolic events. The patient tolerated the procedure well without post-procedural complications and was discharged the next day on oral anticoagulation. We also present a step-by-step approach to perform lead removal with the use of Sentinel™, emphasizing mitigating the stroke and bleeding risks in this patient setting.

Conduction system pacing in prosthetic heart valves.

BACKGROUND: There has been increasing interest in physiologic pacing techniques that directly activate the specialized conduction system. We aimed to assess outcomes of conduction system pacing (CSP) in patients with prosthetic heart valves. METHODS: This systematic review was performed according to PRISMA guidelines. Freeman-Tukey double arcsine transformation with the random-effect model was used to summarize the data. Outcomes studied were 1) implant success (defined as ability to recruit the His-Purkinje system or the distal Purkinje system); (2) lead parameters at implant and follow-up; and (3) procedure-related complications. RESULTS: This systematic review of 7 studies included 267 unique patients in whom CSP was attempted with either HBP or LBBAP for pacing indications after a prosthetic valve. HBP was attempted in 38% (n = 108), while LBBAP in 62% (n = 175) patients. The overall success rate of CSP was 87%, while in patients post-TAVR, the overall success rate was 83.2%. In the subgroup analysis, LBBAP had a significant higher overall success rate compared to HBP (94.3% vs. 76.5%, p interaction = 0.02) and post-TAVR patients (94.3 vs. 66.9%, p interaction < 0.01), respectively. The LBBAP thresholds were significantly lower compared to HBP both at implant (0.67 ± 0.4 @ 0.44 ms vs. 1.35 ± 1 @ 0.85 ms, p interaction < 0.01) and at a mean follow-up of 12.4 ± 8 months (0.73 ± 0.1 @ 0.44 ms vs. 1.39 ± 1 @ 0.85 ms, p interaction < 0.01), respectively. CONCLUSION: CSP is safe and feasible in patients with a prosthetic valve, with a significantly higher success rate and superior lead parameters with LBBAP than HBP, especially in patients post-TAVR.

Racial and Ethnic Disparities in Patients Who Underwent Leadless Pacemaker Implantation.

Evidence regarding racial disparities in leadless pacemaker (LP) utilization and outcomes is limited. We aimed to explore ethnicity-based disparities in LP utilization and clinical outcomes of patients who underwent LP implantation. All consecutive patients who underwent LP between January 2019 and January 2023 at our institution were included. Charts were reviewed for baseline characteristics and clinical outcomes. The primary outcomes were procedure-related complications, cardiac rehospitalization, worsening heart failure (HF) or HF hospitalization, and all-cause mortality. All statistical analyses were performed using SPSS Statistics 22 (IBM Corp., Armonk, NY). The p <0.05 was considered statistically significant. A total of 196 adult patients underwent LP implantation during the study period (48% Caucasians, 36.2% Hispanic, 8.2% Asians, and 7.7% African-American). The groups were balanced with respect to baseline demographics, clinical characteristics, and procedure-related complications. During the median follow-up of 104 days (interquartile range 24 to 382), no statistically significant differences were observed in worsening HF or HF hospitalization or all-cause mortality among the ethnic groups. After multivariable logistic regression, Asian individuals had higher odds of cardiac readmissions (odds ratio 4.1, 95% confidence interval 1.4 to 12.3, p = 0.01). Patients from racial and ethnic minorities face significant inequities in arrhythmia care, including patients who have undergone LP implantation. Awareness and a system-based approach (understanding cultural preferences, effective application of evidence-based guidelines, and population-based policies) are crucial to lessen disparities in health care among minorities.

Statins reduce appropriate implantable cardioverter-defibrillator shocks in ischemic cardiomyopathy with no benefit in nonischemic cardiomyopathy.

Statins have been hypothesized to decrease ventricular arrhythmias through a direct antiarrhythmic effect. Clinical studies have demonstrated a clear reduction only in populations with underlying ischemic heart disease. This study was designed to compare the effect of statins on appropriate shocks between ischemic and nonischemic cardiomyopathy. Patients with an ejection fraction 35% or less who received an implantable cardioverter-defibrillator and had follow-up for at least 1 month were included. The ischemic and nonischemic groups were divided into statin treatment and control subgroups and the occurrence of appropriate shocks was compared. The frequency of shocks was analyzed using negative binomial models to account for overdispersion of the "count" data (number of appropriate shocks) and an adjusted intensity rate ratio was calculated for statin use. A total of 676 patients were included, of which statins were used by 65% (329 of 506) of the ischemic and 42% (72 of 170) of the nonischemic groups. Occurrence of appropriate shocks was significantly reduced with statins in ischemic (13.4% vs 20.9%; relative risk 0.64, P = 0.028), but not in the patients with nonischemic cardiomyopathy. Similarly, although use of statins lowered the intensity rate of appropriate shocks in ischemic patients (intensity rate ratio, 0.23; 95% confidence interval, 0.12-0.47), no such benefit was noted in the nonischemic group (intensity rate ratio, 1.27; 95% confidence interval, 0.37-4.40). In conclusion, statins reduced the occurrence and frequency of appropriate shocks for ventricular arrhythmias in ischemic but not in nonischemic cardiomyopathy. Larger, randomized controlled trials are needed to confirm these findings.

"Catch, Flip, and Remove" Technique for Retrieval of a Hypermobile Detached Leadless Pacemaker: A Case Report and Literature Review.

Leadless pacemaker (LP) detachment is a rare but life-threatening complication that may occur during implantation. While different snaring techniques have been described to remove partially or completely detached LPs, there are currently no reports of snaring a hypermobile LP that travels between different cardiac chambers. This report describes a technique to successfully snare a hypermobile detached LP by first "catching" onto the tines for stabilization with the help of a multi-loop snare, followed by using a second snare for the proximal retrieval feature.