A 66 year old woman with dilated cardiomyopathy, carrier of CRT–D device in secondary prevention since 2013 and a mitralic mechanical prosthesis, suffered of CIED infection, confirmed by PET imaging exam. She was scheduled in our Hospital Unit for transvenous lead extraction. The procedure was performed by the subclavian approach, and the transvenous lead extraction was staged using mechanical telescopic sheats. After the extraction of the atrial and ventricular leads, the advance of the sheats was hampered by tenacious adherences along the site of vascular subclavian access of the coronary sinus lead. Firstly the portion of the lead running inside the coronary sinus was retracted with a pigtail by femoral vein approach. The inability to pass over the tenacious adherences at the point of the subclavian vein access were overcome expanding the surgical field with the help of the Vascular Surgeon, finding out that the adherence was determined by the presence of an osteophyte embracing the lead to the clavicle. The osteophyte was then surgically removed and the lead was finally extracted by jugular vein access. In this case the CIED leads were implanted using a intrathoracic subclavian venous access, where the vein lies behind the medial region of the clavicle. This approach could rarely lead to a periosteal penetration during needle advance that can generate osteophytes between the lead and the bone. In those circumstances the transvenous lead extraction could become extremely complicated, whatever technique is used.

Abstract Funding Acknowledgements Type of funding sources: None. Background Electrical storm is a specific clinical presentation yielding to high morbidity and mortality. Acute development of electrical storms results from the underlying myocardial substrate, autonomic activation, and trigger factors. Main therapeutic approaches range from pharmacological to interventional treatment. Methods We enrolled in a prospective single center registry all patients admitted from March 2018 to March 2022 at our Centre who satisfied diagnostic criteria for electrical storm. Demographic, instrumental, and interventional data were obtained from local electronic health record. Results A total of 87 patients (79% male sex, mean age 72,21±10,49 years) were enrolled. Mean left ventricular ejection fraction was 37,27±11,62%. Underlying cardiomyopathy was ischemic in 57,47%; dilated cardiomyopathy in 20,69%, arrhythmogenic cardiomyopathy in 8%, other in 13,84%. A definite trigger was identified in 34 cases (39%), most frequent ones were sepsis (11 events, 32,4%), acute heart failure (6 events, 17,6%), myocardial ischemia (5 events, 14,7%), thyrotoxicosis (5 events, 14,7%), ionic disorder (4 events, 11,8%). An ICD was already implanted in 89,66% of patients, all remaining patients were implanted during index hospitalization. An ablation strategy was pursued in 65,52% of cases. Mean days from hospitalization to ablation were 7±5. Median hospital stay was 11 days (IQR 8-18). Conclusion In our single referral centre experience, in patients with electrical storm, ischemic cardiomyopathy was the dominant underlying heart disease. An identifiable trigger was found in a large cohort of patients, with sepsis being the most frequent. An ablation strategy was pursued in most cases.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The ELECTRa Registry Outcome Score (EROS) was developed to identify patients at increased transvenous lead extraction (TLE) risk Purpose Aim of the study is to explore the efficiency of EROS for stratifying patients undergoing TLE. Methods We performed a retrospective analysis of 1293 patients who underwent to TLE in our center. We performed extraction procedures with manual traction or mechanical dilatation. We calculated EROS, and we divided patients into 3 groups depending on the EROS class. For this purpose, we made statistical analysis and comparison between EROS 1+2 vs. EROS 3 groups. We used an X2 for among-group comparisons or Fisher’s exact test if the expected cell count was less than five. Results Our analysis included 1293 patients. EROS-1 counted 726 patients (56,1%), EROS-2 367 (28,4%) patients and EROS-3 200 (15,5%) patients. There was no statistical difference in peri-procedural death between EROS-1+2 and EROS-3 (0.18% vs 1.50%, p=0.134). Major complications (0.82% vs. 3.00%, p=0.014), minor complications (3.11% vs. 6.50%, p=0.019) and use of internal jugular approach (6.13% vs. 14.50%, p<0.001) was significantly higher in EROS 3 patients. Conclusion EROS effectively separates patients at higher risk of complications. Use of internal jugular approach was significantly higher in EROS 3 patients.

Abstract Introduction Device related complications are rising the need of Transvenous Lead Removal (TLR). Transvenous extraction of Pacing (PL) and Defibrillating Leads (DL) is a highly effective technique. Aim of this report is to analyse the longstanding experience performed in a single Italian Referral Center. Methods From January 1997 to December 2021, we managed 2925 consecutive patients (2220 men, mean age 65.3 years) with 5370 leads (mean dwell time 74.0 months, range 1–576). PL were 4209 (1903 ventricular, 1801 atrial, 505 coronary sinus leads), DL were 1161 (1140 ventricular, 6 atrial, 15 superior vena cava leads). Indications to TLR were infection in 78% (systemic 27%, local 51%) of leads. We performed mechanical dilatation using a single polypropylene sheath technique and, if necessary, other intravascular tools; we performed an approach through the Internal Jugular Vein (JA) in case of free-floating leads or failure of the standard approach. Results We attempted removal in 5359 leads because the technique was not applicable in 11 PL. Among these, 5223 leads were completely removed (97.4%), 51 (1.0%) were partially removed, 85 (1.6%) were not removed. Among 5271 exposed leads: manual traction removed 879 (16.7%) leads; mechanical dilatation using the venous entry site removed 3860 (73.2%) leads; femoral approach (FA) removed 50 (0.9%) leads; and JA removed 346 (6.6%) leads. All the free-floating leads were completely removed, 26.1% by FA and 73.9% by JA. Major complications occurred in 23 cases (0.78%): cardiac tamponade (21 cases, 5 deaths), hemothorax (2 cases, 1 death). Conclusions Our experience shows that in centers with wide experience, TLR using single sheath mechanical dilatation has a high success rate and a very low incidence of serious complications. TLR through the Internal Jugular Vein increases the effectiveness and safety of the procedure also in case of free-floating or challenging leads. Funding Acknowledgement Type of funding sources: None.

High-power short-duration (HPSD) is an increasingly used ablation strategy for pulmonary vein isolation (PVI) procedures, but Lesion Index (LSI)-guided HPSD radio-frequency (RF) application has not been described in this clinical setting. We evaluated the procedural efficiency and safety of an LSI-guided HPSD strategy for atrial fibrillation (AF) ablation. Paroxysmal and persistent AF patients scheduled for AF ablation were prospectively enrolled and divided in two groups, according to the ablation power used. The LSI-HP Group included patients ablated with a RF power of 50 Watts and the LSI-LP Group included patients ablated with 35 Watts. All patients underwent only PVI under LSI guidance (LSI between 5.5 and 6 anteriorly; LSI between 4.5 and 5 posteriorly) with a point by point strategy and an inter-lesion distance <6 mm. Procedural efficiency parameters were compared between groups. Forty-six patients with AF (60% paroxysmal) were prospectively enrolled, 25 in the LSI-HP Group and 21 in the LSI-LP Group. They were usually male (78%) with a low-intermediate CHA2DS2-Vasc score (1.8±1.1), a preserved ejection fraction (60±6%) and moderate left atrial dilatation (45±6 mm). Baseline clinical characteristics resulted comparable between groups (p=NS). PVI was successful in all patients. RF time (30.22±9.04 vs 47.85±11.87 min, p<0.0001), total procedure time (138.7±33.2 vs 177.6±49.77, p=0.006) and fluoroscopy time (13.92±5.34 vs 23.14±10.97 min, p=0.006) were significantly lower in the LSI-HP Group. No complication or steam pops was seen in either group. LSI-HP AF ablation significantly improves procedural efficiency, reducing ablation time, total procedural duration and fluoroscopy use, while maintaining a comparable safety profile as lower powers. Type of funding sources: None. Figure 1 Figure 2

Abstract Introduction Mapping and ablation of atypical atrial flutter (AFL) continue to be a challenge for clinical electrophysiologists. The advent of high-density (HD) mapping has allowed the generation of electro-anatomic maps with a very high resolution level. Purpose In this single center retrospective analysis, we evaluated the clinical impact of the ultra HD activation sequence mapping compared with the standard low density (LD) ablation catheter mapping technique in the treatment of AFLs. Methods We performed a 7 years-single center retrospective analysis of patients undergoing radiofrequency ablations (RFA) for right and left atypical AFL. We evaluated procedural and clinical outcomes of patients approached with a Low Density (LD) electro-anatomical (EAM) strategy compared with patients mapped with new automatic multipolar HD Mapping (HD Group). Results Seventy-five patients were included. Patients were almost male (60%), relatively old (65±8 years), with a moderate CHA2DS2Vasc score (2.3±1.3), a preserved ejection fraction (58±6) and moderate atrial dilatation (44±7 mm). Baseline clinical characteristics were comparable between groups (p=NS). Among 88 AFLs, 10 (11%) were located in the right and 78 (89%) in the left atrium, including 22 (28%) roof dependent and 37 (47%) mitral dependent (p=NS). Regarding procedural outcomes, Sinus rhythm restoration during ablation was more frequently observed in the HD Group (79% vs 56%, p=0.037), even if no differences in mapping time, procedural time and radiological dose were observed (p=NS). Freedom from AFL/atrial fibrillation (AF) at 1-year was lower in the HD Group (83% vs 45%, p=0.009) with an increased trend for AF recurrences during long term follow-up (17% vs 23% at 1 and 3-years respectively, p=0.059). At the multivariate analysis, HD map (OR 0,17; 95% CI 0,04–0,66) and younger age (OR 1,09; 95% CI 1,01–1,19) were identified as independent predictors of ablation success at 1 year. Conclusions Acute procedural success of ablation of atypical atrial flutter is higher in case of HD mapping strategy. Patient age and HD strategy resulted independent predictors of overall atrial arrhythmias recurrences. During follow-up, AFL recurrences are rare beyond 12 months, differently from AF which continues to show increasing trends. Funding Acknowledgement Type of funding sources: None. Procedural outcomesAtypical atrial flutter HD map

Abstract BACKGROUND Leadless pacemakers have been introduced into the clinical practice as a breakthrough technology that could tackle most of the major sources of complication of traditional pacemakers (PM). The excellent safety profile and optimal electrical performance of Micra have been already largely described, nevertheless the impact on QRS duration has not been investigated so far. We aimed to compare changes in QRS duration after septal Micra implant in comparison to patients who received transvenous right ventricular leads in the same position. METHODS We enrolled all patients who underwent Micra implantation (group 1) at our Center from April 2017 to March 2019. A septal placement was attempted in all cases. Duration of spontaneous and paced QRS and their difference (delta QRS) were measured using a polygraph. To provide a comparison group, we analyzed the QRS duration in a matched group of patients (group 2) who received a traditional single chamber pacing system with a transvenously implanted lead at septal position in the same period. Confounding variables that were used to provide the control group were age, sex, left ventricle ejection fraction, and rhythm at implant. High pacing threshold was defined as ≥1.0 V at pulse duration of 0.24 ms. RESULTS Twenty-eight consecutive patients (mean age 78 ± 3 years; 71.43% males) who underwent successful Micra implant were enrolled. A septal position was achieved in all cases with a single device delivery in 17/28 patients (60.7%). Mean pacing threshold at implant was 0.56 ± 0.34V/0.24 ms with only 3/28 patients (10.7%) presenting a high pacing threshold. No significant differences in demographic, clinical characteristics and ventricular pacing site were observed between groups. QRS duration was slightly longer in group 1 compared to group 2 before implant (median 123 ms (IQR 104-146.5 ms) vs median 116 ms (IQR 90-125 ms); p = 0.09). Nevertheless, there was a significantly lower delta QRS after implant in Micra compared to the traditional pacing group (15.82 ± 31.77 ms vs 35.82 ± 22.13 ms, p = 0.008). CONCLUSION Right ventricular stimulation induces ventricular dyssynchrony, which is correlated with the amount of QRS enlargement after pacing. Micra implant, in a non-apical position, produces significantly smaller changes on the QRS duration in comparison with transvenous lead implanted at the same site, although larger studies are necessary to confirm these results.

Abstract Background Contact force catheter ablation is the gold standard for treatment of atrial fibrillation (AF). Local tissue impedance (LI) evaluation has been recently studied to evaluate lesion formation during radiofrequency ablation. Purpose Aim of the study was to assess the outcomes of an irrigated catether with LI alghorithm compared to contact force (CF)-sensing catheters in the treatment of symptomatic AF. Methods A prospective, single-center, nonrandomized study was conducted, to compare outcomes between CF-AF ablation (Group 1) and LI-AF ablation (Group 2). For Group 1 ablation was performed using the Carto 3© System with the SmartTouch SF catheter and, as ablation target, an ablation index value of 500 anterior and 400 posterior. For Group 2, ablation was performed using the Rhythmia™ System with novel ablation catheter with a dedicated algorithm (DirectSense) used to measure LI at the distal electrode of this catheter. An absolute impedance drop greater than 20Ω was used at each targeted. According to the Close Protocol, ablation included a point by point pulmonary vein isolation (PVI) with an Inter-lesion space ≤5 mm in both Groups. Procedural endpoint was PVI, with confirmed bidirectional block. Results A total of 116 patients were enrolled, 59 patients in Group 1 (CF) and 57 in Group 2 (LI), 65 (63%) with a paroxismal AF and 36 (37%) with a persistent AF. Baseline patients features were not different between groups (P=ns). LI-Group showed a comparable procedural time (180±89 vs 180±56, P=0.59) but with a longer fluoroscopy time (20±12 vs 13±9 min, P=0.002). Wide antral isolation was more often observed in CF-Group (95% vs 80%, P=0.022), while LI-Group 2 required frequently additional right or left carina ablation (28% vs 14%, P=0.013). The mean LI was 106±14Ω prior to ablation and 92.5±11Ω after ablation (mean LI drop of 13.5±8Ω) during a median RF time of 26 [19–34] sec for each ablation spot. No steam pops or complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated in all study patients. Regarding safety, only minor vascular complications were observed (5%), without differences between groups (p=0.97). During follow up, 9-month freedom from atrial fibrillation/atrial flutter/atrial tachycardia recurrence was 86% in Group 1 and 75% in Group 2 (P=0.2). Conclusions An LI-guided PV ablation strategy seems to be safe and effective, with acute and mid-term outcomes comparable to the current contact force strategy. LI monitoring could be a promising complementary parameter to evaluate not only wall contact but also lesion formation during power delivery. Procedural Outcomes Funding Acknowledgement Type of funding source: None

Abstract Background Leadless cardiac pacing is a promising technology in terms of efficacy and safety. Purpose The aim of the study was to compare the long-term clinical and electrical performance of Micra leadless pacemaker with ventricular single-chamber transvenous pacemaker (VVI TV-PM) in a high-volume centre for transvenous lead extraction (TLE). Methods Between May 2014 and April 2019, 100 patients (group 1) underwent Micra implant at our centre. We identified 100 patients (group 2) who underwent VVI TV-PM implant in the same period for a 1:1 comparison matched by age, sex, left ventricular systolic ejection fraction and previous TLE. Results The implant procedure was successful in all patients. In group 1, the procedure duration was lower than in group 2 (43.86 ± 22.38 vs 58.38 ± 17.85 min, p < 0.001), while the fluoroscopy time was longer (12.25 ± 6.84 vs 5.32 ± 4.42 min, p < 0.001). There was no difference about the rate of septal deployment at the right ventricle (group 1 vs group 2: 76% vs 86%, p = 0.10). Patients were followed-up for a median of 12 months. We did not observe any acute and chronic procedure-related complications in group 1, while we reported acute complications in seven patients (0 vs 7%, p = 0.02) and long-term complications in three patients (0 vs 3%, p = 0.24), needing for a system revisions in 6 cases (0 vs 6%, p = 0.038) in group 2. One systemic infection occurred during follow-up in a patient with VVI TV-PM. Electrical measurements were stable during follow-up in both groups, with a longer estimated battery life in group 1 (mean delivered energy at implant group 1 vs group 2: 0.14 ± 0.21 vs 0.26 ± 0.22 μJ, p < 0.001). Conclusion Micra pacemaker implant is a safe and effective procedure, with a lower rate of acute complications and system revisions and a longer estimated battery life compared to VVI TV-PM, even in a real life setting including patients who underwent TLE.

Abstract Background Subcutaneous implantable cardioverter-defibrillator (S-ICD) and leadless pacemakers (LPM) provide an alternative to transvenous implantable devices. Sometimes, after transvenous (TV) lead extraction, patients show a bilateral venous occlusion, resulting not eligible for TV reimplantation. Purpose This analysis was designed to provide preliminary data on feasibility and short-term outcome of an hybrid combination (Hyb) of s-ICD plus LPM after TV-ICD explantation, in patients without anatomical transvenous reimplantation options. Methods Among 2684 consecutive extracted patients, 31 (1.1%) were reimplanted with a LPM, 66 (2.4%) with a s-ICD and 6 (0.2%) patients with an Hyb combination. Hyb strategy was considered in patients with a pacing plus defibrillating indication, and an anatomical barrier, as bilateral superior venous occlusion or massive bilateral skin erosion. Results Hyb patients were old (72±10 years), with a prevalent ischemic disease (4/6) and a reduced ejection fraction (43±16%). Extraction indication was infection in 4 and severe venous occlusion in 2, and included 2 single chamber, 2 dual chamber and 2 biventricular ICD. After extraction, reimplantation timing was 7±6 days, LPM was implanted before and sICD the day after. LPM reimplantation indication was sinus node dysfunction in 2 and AV block in 4. Implantation duration was 68±23 and fluoroscopy time 9.4±2.3 min. ICD reimplantation indication was primary prevention in 4 and secondary prevention in 2. Implantation duration was 118±10 min. No complications were observed. At 1 year, no complications were observed, including device related cross-talks. Conclusions The Hyb strategy is a potential option after TV-ICD explantation in pacemaker dependent patients, when transvenous implantation is not available. Extraction and Reimplantation Session Funding Acknowledgement Type of funding source: None

Introduction:At the present time, there is not strong evidence in the manage of malfunctioning or superfluous leads.On the contrary, an increasing number of procedures is performed in patients with one or more abandoned leads.Purpose: This research has two aims: 1) evaluate the safety and efficacy of the transvenous lead extraction (TLE) in patients with abandoned leads 2) identify predictors of clinical success.Methods: We analyzed all consecutive patients who underwent TLE in our center from January 2009 to December 2017.The primary endpoint was the clinical success of the procedure.Logistic regression was performed to identify predictive factors for clinical success.Results: We analyzed 1210 consecutive patients, who required the extraction of 2343.The group of patients with one or more abandoned leads included 250 patients (21%), with 617 abandoned leads (26%).In this group, there were more leads (median 2.0 vs 3.0; P < 0.001) and older age of the oldest lead (108.00months vs 60.00 months; P < 0.001) than the group without abandoned leads.Clinical success was observed in 1168 patients, with a lower rate in patients with abandoned leads (90.4% vs 98.1%; P < 0.001).Major complications occurred in 13 patients (1.0%), without significant differences among the two groups.Logistic regression showed that the presence of one or more abandoned leads is a predictor of clinical unsuccess (OR: 0.267, 95% IC: 0.0.100-0.711;P ¼ 0.008).Age of the oldest lead lower than 107 months is a predictor for clinical success, whereas the number of leads does not affect the endpoint.Conclusions: Transvenous lead extraction is associated with a high rate of clinical success and a very low rate of major complications.The presence of abandoned leads or a high dwell time are predictors of clinical unsuccess. P83

Abstract Introduction Transvenous lead extraction is a safe and effective procedure. The dwell time of the leads, with other factors, is associated with poor outcome of the procedure. However, a precise estimation of the success of the procedure is not available. Purpose The aim of this study is to identify a lead's age threshold able to predict the success of the transvenous lead extraction (TLE) procedure. Methods All patients who underwent TLE in our center from January 2009 to December 2017 were retrospectively analyzed. The primary endpoint was the clinical success of the procedure. The optimal cut-off threshold was determined by the analysis of Receiver-Operating Characteristics (ROC) curves, using the Youden index. Results We analyzed 1210 consecutive patients that required transvenous removal of 2343 leads (686 ICD leads, 1657 pacemaker leads, 322 coronary sinus leads). Clinical success was achieved in 1168 patients (96.5%). Dwelling time median of the oldest lead for a patient was 66 months (interquartile range 27.0–115.0). The oldest lead completely removed was 32 years old. ROC curve analysis showed a dwell time threshold of 107 months – 8,92 years - for clinical success (Positive Predictive Value: 99.5%; Negative Predictive Value: 7.8%) and the area under the curve (AUC) was 0.879. Comparison of ROC for dwelling time and the 0.5 curve was assessed as statistically significative (p<0.0001). Conclusions Transvenous lead extraction is an effective procedure. The best cut-off threshold to predict a very high clinical success is 107 months.

Ablation of ventricular arrhythmias 1427reentry circuits of ventricular tachycardia (VT), as conducting channels.Adjustments in voltage criteria might unmask potential channels by discriminating subtle areas of healthy tissue.Purpose: To assess the correlation between electrophysiological findings able to identify conducting channels in patients with ischemic VT and bipolar maps using different voltage cutoff values.Methods: Retrospective analysis of 15 patients (86,7% males; 69 years-old [IQR=11]; ejection fraction 30% [IQR 10,8]) with post-infarction VT submitted to substrate guided ablation using CARTO-UNIVU mapping system and Pentaray catheter between october 2015 and september 2017.All patients had an endocardial bipolar voltage map under sinus rhythm (median of total points/map 1563 [IQR 1400]).Electrograms with delayed, high frequency, fractionated and low voltage components (LP) were tagged and correlated with conducting channels.Then, different voltage cutoffs were used to identify scar area and were compared offline with standard voltage cut-off (A: 0,5-1,5; B: 0,3-1,0; C: 0,2-0,8 andD: 0,1-0,5) and correlated with electrophysiological findings.Patients with epicardial or right-sided VTs origin were excluded.Results: A total of 15 patients were included.The percentage of scar decreased as voltage values were lower (A: 76,5cm 2 [IQR 26,2]; B: 61,0cm 2 [IQR 48,8]; C: 47,7cm 2 [IQR 31,1]; D: 26,4cm 2 [IQR 32,8]).With decreasing voltage values, the number of conducting channels increased (A: 0 [IQR 0-2]; B: 1 [IQR0-4]; C: 2 [IQR 1-4]; D: 1 [IQR 0-3]), and a smaller percentage of late potentials was located within dense scar (A: 80,0%; B: 49,3%; C: 40,0%; D: 0%).VT ablation was successful in 80% of the patients.During a median follow-up of 6 months, 2 pts had VT recurrence and 2 died.Conclusions: When voltage cutoffs were changed, conducting channels in the scar and multiple areas with late potentials were revealed (figure 1).The optimal cutoff was 0,2-0,8.

Subcutaneous ICD 621died for septic shock, before re-implantation, because the systemic infection was not resolved despite total extraction of the CIED and specific antibiotic regimen.The external ICD seemed to play no role in this evolution (no changes in blood cultures, confirming that no new pathogens were carried by the device, were observed).Conclusions: An external ICD seems safe and efficacious as a bridge to reimplant in patients explanted for ICD infections who require anti-bradycardia pacing and tachyarrhythmia protection.