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Aims\ud To investigate the abnormalities of the coronary venous system in candidates for cardiac resynchronization therapy (CRT) and describe methods for circumventing the resulting difficulties.\ud \ud Methods\ud From four implanting institutes, data of all CRT implants between October 2008 and October 2020 were screened for abnormal cardiac venous anatomy, defined as an anatomical variation not conforming to the accepted ‘normal’ anatomy. Patient demographics, procedural detail, and subsequent left ventricle (LV) lead pacing indices were collected.\ud \ud Results\ud From a total of 3548 CRT implants, 15 (0.42%) patients (80% male) of 72.2 ± 10.6 years in age with an LV ejection fraction of 34 ± 10.3% were identified to have had an abnormal cardiac venous anatomy over the study period. There were 13 cases of persistent left side superior vena cava (pLSVC), five of which had coronary sinus ostium atresia (CSOA) including two with an “unroofed” coronary sinus (CS); one patient had a unique anomalous origin of the CS and one patient had an isolated CSOA. In total 14 patients (60% repeat attempt) had successful percutaneous implant under general anesthesia (46.7%) via the cephalic vein (59.1%), using the femoral approach (53.3%) for levophase venography and/or pull-through, including one case of endocardial LV implant. Pacing follow-up over 37.64 ± 37.6 months demonstrated LV lead threshold between 0.62 and 2.9 volts (pulsewidth 0.4–1.5 ms) in all cases; five patients died within 2.92 ± 1.6 years of a successful implant.\ud \ud Conclusion\ud CRT devices can be implanted percutaneously even in the presence of substantial abnormalities of coronary venous anatomy. Alternative routes of venous access may be required.

INTRODUCTION Before ablation, predicting the site of origin (SOO) of outflow tract ventricular arrhythmia (OTVA), can inform patient consent and facilitate appropriate procedural planning. We set out to determine if OTVA variability can accurately predict SOO. METHODS Consecutive patients with a clear SOO identified at OTVA ablation had their prior 24-h ambulatory ECGs retrospectively analysed (derivation cohort). Percentage ventricular ectopic (VE) burden, hourly VE values, episodes of trigeminy/bigeminy, and the variability in these parameters were evaluated for their ability to distinguish right from left-sided SOO. Effective parameters were then prospectively tested on a validation cohort of consecutive patients undergoing their first OTVA ablation. RESULTS High VE variability (coefficient of variation ≥0.7) and the presence of any hour with

Background The Sars-Cov-2 infection is a multisystem illness that can affect the cardiovascular system. Tachyarrhythmias have been reported but the prevalence of bradyarrhythmia is unclear. Cases have been described of transient high-degree atrioventricular (AV) block in COVID-19 that were managed conservatively. Method A database of all patients requiring temporary or permanent pacing in 2 linked cardiac centres was used to compare the number of procedures required during the first year of the pandemic compared to the corresponding period a year earlier. The database was cross-referenced with a database of all patients testing positive for Sars-Cov-2 infection in both institutions to identify patients who required temporary or permanent pacing during COVID-19. Results The number of novel pacemaker implants was lower during the COVID-19 pandemic than the same period the previous year (540 vs 629, respectively), with a similar proportion of high-degree AV block (38.3% vs 33.2%, respectively, p = 0.069). Four patients with the Sars-Cov-2 infection had a pacemaker implanted for high-degree AV block, 2 for sinus node dysfunction. Of this cohort of six patients, two succumbed to the COVID-19 illness and one from non-COVID sepsis. Device interrogation demonstrated a sustained pacing requirement in all cases. Conclusion High-degree AV block remained unaltered in prevalence during the COVID-19 pandemic. There was no evidence of transient high-degree AV block in patients with the Sars-Cov-2 infection. Our experience suggests that all clinically significant bradyarrhythmia should be treated by pacing according to usual protocols regardless of the COVID status. This article is protected by copyright. All rights reserved.

The IMPACT study established the role of controlled esophageal cooling in preventing esophageal thermal injury during radiofrequency (RF) ablation for atrial fibrillation (AF). The effect of esophageal cooling on ablation lesion delivery and procedural and patient outcomes had not been previously studied. The objective was to determine the effect of esophageal cooling on the formation of RF lesions, the ability to achieve procedural endpoints, and clinical outcomes.Participants in the IMPACT trial underwent AF ablation guided by Ablation Index (30 W at 350-400 AI posteriorly, 40 W at ≥450 AI anteriorly). A blinded 1:1 randomization assigned patients to the use of the ensoETM® device to keep esophageal temperature at 4°C during ablation or standard practice using a single-sensor temperature probe. Ablation parameters and clinical outcomes were analyzed.Procedural data from 188 patients were analyzed. Procedure and fluoroscopy times were similar, and all pulmonary veins were isolated. First-pass pulmonary vein isolation and reconnection at the end of the waiting period were similar in both randomized groups (51/64 vs. 51/68; p = 0.54 and 5/64 vs. 7/68; p = 0.76, respectively). Posterior wall isolation was also similar: 24/33 versus 27/38; p = 0.88. Ablation effect on tissue, measured in impedance drop, was no different between the two randomized groups: 8.6Ω (IQR: 6-11.8) versus 8.76Ω (IQR: 6-12.2; p = 0.25). Arrhythmia recurrence was similar after 12 months (21.1% vs. 24.1%; 95% CI: 0.38-1.84; HR: 0.83; p = 0.66).Esophageal cooling has been shown to be effective in reducing ablation-related thermal injury during RF ablation. This protection does not compromise standard procedural endpoints or clinical success at 12 months.

Background Transvenous lead extraction (TLE) plays a critical role in managing patients with cardiovascular implantable electronic devices. Mechanical TLE tools, including rotational sheaths, are used to overcome fibrosis and calcification surrounding leads. Prospective clinical data are limited regarding the safety and effectiveness of use of mechanical TLE devices, especially rotational tools. Objective To prospectively investigate the safety and effectiveness of mechanical TLE in real-world usage. Methods Patients were enrolled at 10 sites in the United States and Europe to evaluate the use of mechanical TLE devices. Clinical success, complete procedural success, and complications were evaluated through follow-up (median, 29 days). Patient data were source verified and complications were adjudicated by an independent clinical events committee (CEC). Results Between October 2018 and January 2020, mechanical TLE tools, including rotational sheaths, were used to extract 460 leads with a median indwell time of 7.4 years from 230 patients (mean age 64.3 ± 14.4 years). Noninfectious indications for TLE were more common than infectious indications (61.5% vs 38.5%, respectively). The extracted leads included 305 pacemaker leads (66.3%) and 155 implantable cardioverter-defibrillator leads (33.7%), including 85 leads with passive fixation (18.5%). A bidirectional rotational sheath was needed for 368 leads (88.0%). Clinical success was obtained in 98.7% of procedures; complete procedural success was achieved for 96.3% of leads. CEC-adjudicated device-related major complications occurred in 6 of 230 (2.6%) procedures. No isolated superior vena cava injury or procedural death occurred. Conclusion This prospective clinical study demonstrates that use of mechanical TLE tools, especially bidirectional rotational sheaths, are effective and safe., Graphical abstract

Background Cardiac resynchronization therapy-defibrillator (CRT-D) implantation via the cephalic vein is feasible and safe. Recent evidence has suggested a higher implantable cardioverter-defibrillator (ICD) lead failure in multi-lead defibrillator therapy via the cephalic route. We evaluated the relationship between CRT-D implantation via the cephalic and ICD lead failure. Methods Data was collected from three CRT-D implanting centers between October 2008 and September 2017. In total 633 patients were included. Patient and lead characteristics with ICD lead failure were recorded. Comparison of "cephalic" (ICD lead via cephalic) versus "non-cephalic" (ICD lead via non-cephalic route) cohorts was performed. Kaplan-Meier survival and a Cox-regression analysis were applied to assess variables associated with lead failure. Results The cephalic and non-cephalic cohorts were equally male (81.9% vs. 78%; p = .26), similar in age (69.7 ± 11.5 vs. 68.7 ± 11.9; p = .33) and body mass index (BMI) (27.7 ± 5.1 vs. 27.1 ± 5.7; p = .33). Most ICD leads were implanted via the cephalic vein (73.5%) and patients had a mean of 2.9 ± 0.28 leads implanted via this route. The rate of ICD lead failure was low and statistically similar between both groups (0.36%/year vs. 0.13%/year; p = .12). Female gender was more common in the lead failure cohort than non-failure (55.6% vs. 17.9%, respectively; p = .004) as was hypertension (88.9% vs. 54.2%, respectively, p = .038). On multivariate Cox-regression, female sex (p = .008; HR, 7.12 [1.7-30.2]), and BMI (p = .047; HR, 1.12 [1.001-1.24]) were significantly associated with ICD lead failure. Conclusion CRT-D implantation via the cephalic route is not significantly associated with premature ICD lead failure. Female gender and BMI are predictors of lead failure.

Aims Thermal injury to the oesophagus is an important cause of life-threatening complication after ablation for atrial fibrillation (AF). Thermal protection of the oesophageal lumen by infusing cold liquid reduces thermal injury to a limited extent. We tested the ability of a more powerful method of oesophageal temperature control to reduce the incidence of thermal injury. Methods and results A single-centre, prospective, double-blinded randomized trial was used to investigate the ability of the ensoETM device to protect the oesophagus from thermal injury. This device was compared in a 1:1 randomization with a control group of standard practice utilizing a single-point temperature probe. In the protected group, the device maintained the luminal temperature at 4°C during radiofrequency (RF) ablation for AF under general anaesthesia. Endoscopic examination was performed at 7 days post-ablation and oesophageal injury was scored. The patient and the endoscopist were blinded to the randomization. We recruited 188 patients, of whom 120 underwent endoscopy. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 vs. 2/60; P = 0.008), with a trend toward reduction in gastroparesis (6/60 vs. 2/60, P = 0.27). There was no difference between groups in the duration of RF or in the force applied (P value range= 0.2–0.9). Procedure duration and fluoroscopy duration were similar (P = 0.97, P = 0.91, respectively). Conclusion Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared with standard care. This method of oesophageal protection is safe and does not compromise the efficacy or efficiency of the ablation procedure.

Background Cardiac perforation caused by cardiac rhythm device implantation is uncommon but potentially lethal. Methods All patients presenting to a single referral centre with cardiac perforation after implantation between December 2017 and July 2019 were identified. Patient demographics, time to diagnosis, the method of lead extraction and 30-day complications were examined. Results Thirteen cases of cardiac perforation were identified, 4 of which were implanted at other hospitals. The incidence of perforation for devices implanted at our institution was 9/1031 (0.87%). Median time from implantation to diagnosis was 8 days (IQR = 3–21). Compared with implantations during the same time period, patients with perforation were older (80 ± 10 years vs. 73 ± 15 years, P = 0.005) and predominantly females (9/13 vs. 355/1031, P = 0.009). In all cases, the perforating lead was an active fixation model, an ICD coil in one case. 10 leads were in the right ventricle (3 of which in apical position) and 3 in the right atrium (all in the lateral wall). There was no greater proportion of a particular lead type compared with implantations during the same time period. All had abnormal electrical parameters at device interrogation. Nine patients (69%) had pericardial effusion and four (31%) developed tamponade. Transvenous lead extraction was successfully performed in all 13 patients, with no 30-day mortality. Conclusion Older age and female gender were more prevalent in patients with lead perforation. Transvenous lead extraction was safely performed in all patients.

COVID-19 causes severe illness that results in morbidity and mortality. Electrocardiographic features, including QT prolongation, have been associated with poor acute outcomes; data on the medium-term outcomes remain scarce. This study evaluated the 1-year outcomes of patients who survived the acute COVID-19 infection. Methods and Materials: Data of the 159 patients who survived the COVID-19 illness during the first wave (1 March 2020–18 May 2020) were collected. Patient demographics, laboratory findings and electrocardiography data were evaluated. Patients who subsequently died within 1-year of the index illness were compared to those who remained well. Results: Of the 159 patients who had survived the index illness, 28 (17.6%) subsequently perished within 1-year. In comparison to the patients that were alive after 1-year, the deceased were older (68 vs. 83 years, p < 0.01) and equally male (60.4% vs. 53.6%, p = 0.68), with a similar proportion of hypertension (59.5% vs. 57.1%, p = 0.68), diabetes (25.2% vs. 39.2%, p = 0.096) and ischaemic heart disease (11.5% vs. 7.1%, p = 0.54). The QTc interval for the alive and deceased patients shortened by a similar degree from the illness to post-COVID (−26 ± 33.5 vs. −20.6 ± 30.04 milliseconds, p = 0.5); the post-COVID R-R interval was longer in the alive patients compared to the deceased (818.9 ± 169.3 vs. 761.1 ± 61.2 ms, p = 0.02). A multivariate Cox regression analysis revealed that age (HR1.098 [1.045–1.153], p < 0.01), diabetes (HR3.972 [1.47–10.8], p < 0.01) and the post-COVID R-R interval (HR0.993 [0.989–0.996], p < 0.01) were associated with 1-year mortality. Conclusions: The COVID-19-associated mortality risk extends to the post-COVID period. The QTc does recover following the acute illness and is not associated with outcomes; the R-R interval is a predictor of 1-year mortality.

INTRODUCTION: Research evidence has shown that catheter ablation is a safe and superior treatment for atrial fibrillation (AF) compared to medical therapy, but real-world practice has been slow to adopt an early interventional approach. This study aims to determine the cost effectiveness of catheter ablation compared to medical therapy from the perspective of the United Kingdom. METHODS: A patient-level Markov health-state transition model was used to conduct a cost-utility analysis. The population included patients previously treated for AF with medical therapy, including those with heart failure (HF), simulated over a lifetime horizon. Data sources included published literature on utilization and cardiovascular event rates in real world patients, a systematic literature review and meta-analysis of randomized controlled trials for AF recurrence, and publicly available government data/reports on costs. RESULTS: Catheter ablation resulted in a favorable incremental cost-effectiveness ratio (ICER) of £8614 per additional quality adjusted life years (QALY) gained when compared to medical therapy. More patients in the medical therapy group failed rhythm control at any point compared to catheter ablation (72% vs. 24%) and at a faster rate (median time to treatment failure: 3.8 vs. 10 years). Additionally, catheter ablation was estimated to be more cost-effective in patients with AF and HF (ICER = £6438) and remained cost-effective over all tested time horizons (10, 15, and 20 years), with the ICER ranging from £9047-£15 737 per QALY gained. CONCLUSION: Catheter ablation is a cost-effective treatment for atrial fibrillation, compared to medical therapy, from the perspective of the UK National Health Service.

Atrioesophageal fistula is a life-threatening complication of ablation treatment for atrial fibrillation. Methods to reduce the risk of esophageal injury have evolved over the last decade, and diagnosis of this complication remains difficult and therefore challenging to treat in a timely manner. Delayed diagnosis leads to treatment occurring in the context of a critically ill patient, contributing to the poor prognosis associated with this complication. The associated mortality risk can be as high as 70%. Recent important advances in preventative techniques are explored in this review. Preventative techniques used in current clinical practice are discussed, which include high-power short-duration ablation, esophageal temperature probe monitoring, cryotherapy and laser balloon technologies, and use of proton pump inhibitors. A lack of randomized clinical evidence for the effectiveness of these practical methods are found. Alternative methods of esophageal protection has emerged in recent years, including mechanical deviation of the esophagus and esophageal temperature control (esophageal cooling). Although these are fairly recent methods, we discuss the available evidence to date. Mechanical deviation of the esophagus is due to undergo its first randomized study. Recent randomized study on esophageal cooling has shown promise of its effectiveness in preventing thermal injuries. Lastly, novel ablation technology that may be the future of esophageal protection, pulsed field ablation, is discussed. The findings of this review suggest that more robust clinical evidence for esophageal protection methods is warranted to improve the safety of atrial fibrillation ablation.

Purpose: Ablation index (AI) is a radiofrequency lesion quality marker. The AI value that allows effective and safe pulmonary vein isolation (PVI) is still debated. We evaluated the incidence of acute and late PV reconnection (PVR) with different AI settings and its predictors. Methods: The Ablation Index Registry is a multicenter study that included patients with paroxysmal/persistent atrial fibrillation (AF) who underwent first-time ablation. Each operator performed the ablation using his preferred ablation catheter (ThermoCool® SmartTouch or Surround Flow) and AI setting (380 posterior-500 anterior and 330 posterior-450 anterior). We divided the study population into two groups according to the AI setting used: group 1 (330–450) and group 2 (380–500). Incidence of acute PVR was validated within 30 min after PVI, whereas the incidence of late PVR was evaluated at repeat procedure. Results: Overall, 490 patients were divided into groups 1 (258) and 2 (232). There was no significant difference in the procedural time, fluoroscopy time, and rate of the first-pass PVI between the two study groups. Acute PVR was observed in 5.6% PVs. The rate of acute PVR was slightly higher in group 2 (64/943, 6.8%, PVs) than in group 1 (48/1045, 4.6% PVs, p = 0.04). Thirty patients (6%) underwent a repeat procedure and late PVR was observed in 57/116 (49%) PVs (number of reconnected PV per patient of 1.9 ± 1.6). A similar rate of late PVR was found in the two study groups. No predictors of acute and late PVR were found. Conclusion: Ablation with a lower range of AI is highly effective and is not associated with a higher rate of acute and late PVR. No predictors of PV reconnection were found.

Accessory pathways are present in 1 in 300 young individuals. They are often asymptomatic and potentially lethal arrhythmias may be the first presentation. During long‐term follow‐up, up to 20% of asymptomatic individuals with pre‐excitation go on to develop an arrhythmia and the absence of traditional clinical and electrophysiological high‐risk markers does not guarantee the “safe” nature of an accessory pathway. The widespread availability of permanent cure for the condition at low risk by catheter ablation, creates an incentive to screen for accessory pathways with a 12‐lead ECG, particularly in individuals who are perceived to be at increased risk, such as athletes and high‐risk professions. We review the existing literature on the assessment and management of accessory pathways (Wolff‐Parkinson‐White [WPW] syndrome) and discuss its implications for the young athletic population.

Purpose The effect of adding contact force (CF) sensing to 56-hole tip irrigation in ventricular arrhythmia (VA) ablation has not been previously studied. We aimed to compare outcomes with and without CF sensing in VA ablation using a 56-hole radiofrequency (RF) catheter. Methods A total of 164 patients who underwent first-time VA ablation using Thermocool SmartTouch Surround Flow (TC-STSF) catheter (Biosense-Webster, Diamond Bar, CA, USA) were propensity-matched in a 1:1 fashion to 164 patients who had first-time ablation using Thermocool Surround Flow (TC-SF) catheter. Patients were matched for age, gender, cardiac aetiology, ejection fraction and approach. Acute success, complications and long-term follow-up were compared. Results There was no difference between procedures utilising either TC-SF or TC-STSF in acute success (TC-SF: 134/164 (82%), TC-STSF: 141/164 (86%), p = 0.3), complications (TC-SF: 11/164 (6.7%), TC-STSF: 11/164 (6.7%), p = 1.0) or VA-free survival (TC-SF: mean arrhythmia-free survival time = 5.9 years, 95% CI = 5.4–6.4, TC-STSF: mean = 3.2 years, 95% CI = 3–3.5, log-rank p = 0.74). Fluoroscopy time was longer in normal hearts with TC-SF (19 min, IQR: 14–30) than TC-STSF (14 min, IQR: 8–25; p = 0.04). Conclusion Both TC-SF and TC-STSF catheters are safe and effective in treating VAs. The use of CF sensing catheters did not improve safety or acute and long-term outcomes, but reduced fluoroscopy time in normal heart VA.

Injury to structures adjacent to the heart, particularly oesophageal injury, accounts for a large proportion of fatal and life-altering complications of ablation for persistent AF. Avoiding these complications dictates many aspects of the way ablation is performed. Because avoidance involves limiting energy delivery in areas of interest, fear of extracardiac injury can impede the ability of the operator to perform an effective procedure. New techniques are becoming available that may permit the operator to circumvent this dilemma and deliver effective ablation with less risk to adjacent structures. The authors review all methods available to avoid injury to extracardiac structures to put these developments in context.

Background Left atrial posterior wall (LAPW) isolation is an adjunct to pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF). Objective To compare the effect of LAPW box isolation with LAPW point-by-point ablation and PVI in persistent AF on 12-month arrhythmia-free survival and procedure complications. Methods 77 consecutive patients who underwent LAPW box isolation, 24 patients who underwent LAPW point-by-point ablation and 101 patients who underwent PVI for persistent AF were compared. All patients had undergone no prior ablation for AF and were followed up for one year. Results Mean time to atrial tachyarrhythmia recurrence was similar with LAPW box isolation (9.8 months, 95% CI = 9-10.7) and LAPW point-by-point ablation (10 months, 95% CI = 8.6-11.3), both were longer than PVI (8.2 months, 95% CI = 7.4-9.1, log-rank p = 0.003). There was no difference in peri-procedural complications (LAPW box isolation: 5/77, LAPW point-by-point ablation: 1/24, PVI: 6/101, p = 0.91). At 12 months, no difference in atrial tachyarrhythmia recurrence was observed between box isolation (23/77, 30%) and point-bypoint ablation (11/24, 46%, p = 0.15), but significantly higher recurrence occurred with PVI alone (58/101, 57%, p Conclusion In persistent AF, there was no difference between LAPW box isolation and point-by-point ablation in terms of mean arrhythmia-free survival, 12-month recurrence or procedure complications. Arrhythmia-free survival with either technique was longer than PVI alone, with no increase in complications.

Randomised evidence supports an early rhythm control strategy as treatment for AF, and catheter ablation outperforms medical therapy in terms of effectiveness when studied as first- and second-line treatment. Despite evidence consistently showing that catheter ablation treatment is superior to medical therapy in most AF patients, only a small proportion receive ablation, in some cases after a prolonged trial of ineffective medical therapy. Health economics research in electrophysiology remains limited but is recognised as being important in influencing positive change to ensure early access to ablation services for all eligible patients. Such information has informed the updated recommendations from the recently published National Institute for Health and Care Excellence clinical guideline on the diagnosis and management of AF, but increased awareness is needed to drive real-world adoption and to ensure patients are quickly referred to specialists. In this article, economic evaluations of catheter ablation versus medical therapy are reviewed.

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Dr Leung has received research support from Attune Medical (Chicago, IL). Dr Gallagher has received research funding from Attune Medical (Chicago, IL). Background Randomized evidence has shown that controlled oesophageal cooling is effective at reducing oesophageal thermal injury during radiofrequency (RF) ablation for atrial fibrillation (AF) compared to standard care. The effect of oesophageal cooling on ablation lesion formation in left atrial myocardium and patient outcomes at 12-months had not been previously studied. Purpose To determine the effect of oesophageal cooling on the formation of RF lesions, the ability to achieve procedural endpoints and long-term patient outcomes compared to standard care ablations. Methods Ablation results and patient outcomes from a double-blind randomized controlled trial were analysed (IMPACT trial NCT03819946). AF ablation was guided by Ablation Index technology (30W at 350-400 AI posteriorly, 40W at 450 AI anteriorly). A blinded 1:1 randomization assigned patients to the use of an oesophageal temperature control device to keep oesophageal temperature at 4 degrees during ablation or standard practice using a single-sensor temperature probe. Ablation parameters and 12-month outcomes were analysed. Results We recruited 188 patients. Procedure and fluoroscopy times were similar. First pass pulmonary vein isolation and reconnection at the end of the waiting period were similar in both randomized groups (51/64 vs 51/68; p = 0.54 and 5/64 vs 7/68; p = 0.76, respectively). Posterior wall isolation was also similar: 24/33 vs 27/38; p = 0.88. Ablation effect on myocardial tissue, measured in impedance drop, was also similar: 8.6Ω (IQR: 6-11.8) vs 8.76Ω (IQR: 6-12.2; p = 0.25) and median catheter tip temperature was the same at 25.5 degrees. Arrhythmia recurrence was similar at 12 months (20.3% vs 26.8%, from 142 completed assessments; p = 0.66). Conclusions Oesophageal cooling has been shown to be effective in reducing ablation-related oesophageal thermal injury during RF ablation. Ablation data show that this protection does not make it any more difficult to achieve standard procedural endpoints or clinical success at 12-months. Abstract Figure. Pyramid frequency plots of AI values

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Dr Leung has received research support from Attune Medical (Chicago, IL). Dr Gallagher has received research funding from Attune Medical (Chicago, IL). Background Thermal injury to the oesophagus causes a spectrum of adverse effects after ablation for atrial fibrillation (AF); at the most severe end, atrio-oesophageal fistula carries a high mortality rate. Controlled active thermal protection in the oesophagus during ablation is the most promising method of oesophageal protection. Randomized evidence from the IMPACT trial (NCT03819946) showed an 83.4% reduction in endoscopically detected oesophageal lesions compared to standard care when an oesophageal temperature control device was used to control the local temperature. The IMPACT patients who were randomized to the use of the device had no adverse event related to its use. Real world registry data on applications of this device have not previously been available. Purpose To determine the safety of an oesophageal temperature control device by review of real-world registry data on its clinical use and any reported device-related adverse events. Methods We reviewed the following databases for any reported oesophageal temperature control device-related complications: The United States Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE), FDA Medical and Radiation Emitting Device Recalls, the Medicines and Healthcare products Regulatory Agency (MHRA) Medical Device Alerts and SwissMedic records of Field Safety Corrective Actions (FSCA). An internal registry (post-marketing follow up) database maintained by the manufacturer of the device was used to quantify the number used for each indication. Reported events were reviewed and catalogued for description and identification of any events related to its use in the cardiac electrophysiology lab. The IMPACT study patients were reviewed for any device-related events. Results Of the 13, 284 oesophageal temperature control devices used, 2532 were recorded as having been used for the purpose of oesophageal protection during catheter ablation for AF. A total of 5 events associated with the device were identified, all from the MAUDE database. Three were from 2017, one from 2018, and one from 2019. All involved its use in critical care or trauma patients and were related to user error or contraindicated patient selection; none resulted in serious harm to the patient. No adverse events occurred related to its use in the cardiac electrophysiology lab. No case of clinically significant oesophageal injury was reported in a patient who had been protected by the oesophageal temperature control device. Conclusions Real world registry data has shown no adverse events reported to date in over 2500 uses of an oesophageal temperature control device in the cardiac electrophysiology lab, for the purpose of active thermal protection. This data supports the randomized trial evidence of its clinical effectiveness. Abstract Figure. Oesophageal active thermal protection

Funding Acknowledgements Type of funding sources: None. Background Cardiac perforation is an uncommon but life-threatening complication of cardiac implantable electronic device (CIED) implantation. Management strategy commonly relies on diagnostic Computed Tomography (CT) imaging and cardiac surgery. Emerging evidence has indicated a diversion from this approach. Transvenous culprit lead revision has been shown to be safe and efficacious in limited series. We sought to evaluate the outcomes of transvenous lead revision in patients with cardiac perforation. Method Data was collected retrospectively of patients admitted to a single tertiary centre with CIED-related cardiac perforation between December 2013 – October 2019. Transvenous lead revision was performed as standard with cardiac surgery on standby. Patient demographics, use of CT imaging, method of removal and 30-day outcomes were recorded. Results Of the 46 recorded CIED-related cardiac perforations, the majority occurred in female patients (63%) and hypertensives (61%), whilst a proportion had cancer (20%) and ischaemic heart disease (30%). The culprit in most cases was a standard pacing lead (92%) of an active fixation (98%) in the right ventricle (80%) positioned at the ventricular apex (65%). The median time to presentation from implant was 14 days [IQR 4-50 days] with chest pain (44%); abnormal pacing indices was highly prevalent (95%) whilst a pericardial effusion was noted in the majority of cases (57%). CT scanning was performed in 19 cases (41%) for various indications but deemed essential in only 4, all of which had non-diagnostic pacing indices and imaging. Chest X-ray (CXR) found clear perforation, lead displacement or pleural effusion in 74% of cases, whilst an echocardiogram found these in 64% of cases. The culprit lead was replaced in the majority of cases (87%) under local anaesthesia (76%) with surgical backup. The median hospital stay was 7 days [IQR 3-10 days] with zero procedural and 30-day mortality. Conclusion Transvenous lead revision for CIED-related cardiac perforation is safe and efficacious. CT modality for diagnostic purposes is useful in providing incremental value in a minority of cases; patients with non-diagnostic pacing parameters and non-CT imaging benefit most from this.

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): This research study was funded by Biosense Webster, Inc. Dr Leung has received research support from Attune Medical (Chicago, IL) towards a research fellowship at St. George"s University of London. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. Background Randomised data on patient-related outcomes comparing catheter ablation to medical therapy for the treatment of atrial fibrillation (AF) have shown the effectiveness of catheter ablation. Ablation versus medical therapy should also be analysed from a health economics perspective to achieve optimal healthcare resource allocation. Purpose To determine the cost effectiveness of catheter ablation compared to medical therapy for the treatment of atrial fibrillation, from the perspective of the UK National Health Service. Methods A patient-level Markov health-state transition model was used to conduct a cost utility analysis comparing catheter ablation and medical therapy for the treatment of AF. A systematic review and meta-analysis of catheter ablation treatment versus medical therapy (rhythm and/or rate control drugs) was conducted to enable comparison of AF recurrence between treatment groups utilising the model. Additional model parameters were established based upon a best-evidence review of the literature. The model simulated care delivered from a secondary care perspective. Total patients simulated in this model over a lifetime were 250,000, with patients entering the model at age 64. Only previously treated AF patients were included, including those with concomitant heart failure. A separate scenario analysis was conducted to determine the cost effectiveness specifically in the cohort of patients with AF and heart failure. Main outcomes measures Incremental cost-effectiveness ratio (ICER) and average total expected costs and quality-of-life years (QALYs) incurred over the lifetime of a patient. AF recurrence, complications and cardiovascular adverse events were compared over the total duration inside the model. Results In the base case analysis, catheter ablation resulted in a favourable ICER of £8,614 per additional QALY gained when compared to medical therapy, well below the national Willingness-to-Pay threshold of £20,000. Catheter ablation was associated with an expected increase of 1.01 QALYs, while adding an additional cost £8,742 over a patient’s lifetime. The cost-effectiveness of catheter ablation was improved in the heart failure sub-group analysis, with an ICER of £6,438. A significantly greater proportion of patients in the medical therapy group failed rhythm control at any stage compared to catheter ablation (72% vs 24%) and at a faster rate (median time to treatment failure: 3.8 vs 10 years). Conclusion Catheter ablation appears to be a highly cost-effective treatment for atrial fibrillation, compared to medical therapy, from the perspective of the UK National Health Service. With low rates of adverse events and superiority in achieving rhythm control, AF ablation services should be prioritised with appropriate allocation of healthcare resources.

Funding Acknowledgements Type of funding sources: None. OnBehalf PROMET group Background As implantation of cardiac implantable devices (CIED) rises globally, there is a paralleled need for extraction of these devices. Indications for transvenous lead extraction (TLE) is expanding, fuelling demand. This lifesaving procedure is performed by cardiologists and cardiac surgeons (CS). Cardiologists are familiar with transvenous methods whilst cardiac surgeons possess the skillset to address the significant complications associated with this procedure. We compared non-laser TLE outcomes performed by cardiologists and cardiac surgeons from six high-volume extraction centres across Europe. Methods Data was collected retrospectively from six major European TLE centres of 2205 patients and 3849 leads (PROMET). Propensity 1:1 score matching (PSM) was performed to account for confounding variables. PSM model with variables: lead dwell time, infection indication, biventricular system and defibrillator device, was best matched. This dataset was analysed to compare outcomes of TLE performed by the cardiologists and CS. Predictors of 30-day mortality and complications were identified using a multivariate regression analysis. Results Patients treated by CS and cardiologists were similar in age (64.7 vs 66.7 years, p = NS) and equally male (70.3% vs 72.3%, p = 0.39) with a parallel infectious indication (51.7% vs 47.6%, p = 0.1). Surgeons achieved a significantly higher proportion of clinical success than cardiologists (98.9% vs 96.4%, p = 0.001) and complete lead extraction (98% vs 95.9%, p Conclusion Cardiac surgeons and cardiologists achieved a high rate of TLE procedural success and with a similar safety profile, replicating standards seen across Europe.

Funding Acknowledgements Type of funding sources: None. OnBehalf PROMET group Background Cardiac implantable electronic devices (CIEDs) improve morbidity and mortality. This has fuelled an upsurge in implantation of these devices across all patient cohorts, simultaneously increasing the need for transvenous lead extractions (TLE). As the global population expands and life-expectancy extends, TLE will play a significant role in CIED management. Advancing patient age is a recognised risk factor for poor outcomes however the association between patient age and TLE outcomes remains unclear. We sought to evaluate the relationship between patient age and non-laser TLE outcomes. Method Data of 2205 patients (3849 leads) was collected retrospectively from six high-volume TLE institutes across Europe (PROMET) between January 2005-December 2018. Propensity 1:1 score matching was performed to limit the effects of confounding variables, pairing 353 patients in the >80 years of age category with 353 patients in Results In the 80 years-of-age cohorts, there was a similar proportion of male patients (65.3% vs 67.9%, p = 0.47) treated under general anaesthesia (96.5% vs 93.4%, p = 0.078) for a pre-dominant infectious indication (56.7% vs 60.3%, p = 0.52) but with a higher requirement of the EvolutionTM sheath in the octogenarians (39.4% vs 48.4%, p = 0.015). A similar clinical success per lead was achieved between the two age groups (96.6% vs 98%, 80 years, p = 0.245) as was complete lead extraction (95.5% vs 96.6%, 80 years, p = 0.44) with a comparable minor complication rate (2.3% vs 3.1%, 80 years, p = 0.29) and major complications (1.1% vs 1.4%, 80 years, p = 0.74). Thirty-day mortality was higher in the octogenarian cohort than the Conclusion Transvenous lead extraction is similar in efficacy and safety across all age groups. Thirty-day mortality is higher in the advanced age group, signifying the importance of post-procedural management in this cohort.

Coronavirus disease-2019 (COVID-19) causes severe illness and multi-organ dysfunction. An abnormal electrocardiogram is associated with poor outcome, and QT prolongation during the illness has been linked to pharmacological effects. This study sought to investigate the effects of the COVID-19 illness on the corrected QT interval (QTc).For 293 consecutive patients admitted to our hospital via the emergency department for COVID-19 between 01/03/20 -18/05/20, demographic data, laboratory findings, admission electrocardiograph and clinical observations were compared in those who survived and those who died within 6 weeks. Hospital records were reviewed for prior electrocardiograms for comparison with those recorded on presentation with COVID-19.Patients who died were older than survivors (82 vs 69.8 years, p 0.001), more likely to have cancer (22.3% vs 13.1%, p = 0.034), dementia (25.6% vs 10.7%, p = 0.034) and ischemic heart disease (27.8% vs 10.7%, p 0.001). Deceased patients exhibited higher levels of C-reactive protein (244.6 mg/L vs 146.5 mg/L, p 0.01), troponin (1982.4 ng/L vs 413.4 ng/L, p = 0.017), with a significantly longer QTc interval (461.1 ms vs 449.3 ms, p = 0.007). Pre-COVID electrocardiograms were located for 172 patients; the QTc recorded on presentation with COVID-19 was longer than the prior measurement in both groups, but was more prolonged in the deceased group (448.4 ms vs 472.9 ms, pre-COVID vs COVID, p 0.01). Multivariate Cox-regression analysis revealed age, C-reactive protein and prolonged QTc of 455 ms (males) and 465 ms (females) (p = 0.028, HR 1.49 [1.04-2.13]), as predictors of mortality. QTc prolongation beyond these dichotomy limits was associated with increased mortality risk (p = 0.0027, HR 1.78 [1.2-2.6]).QTc prolongation occurs in COVID-19 illness and is associated with poor outcome.

BACKGROUND: Small series has shown that cardiac resynchronisation therapy (CRT) can be achieved in a majority of patients using exclusively cephalic venous access. We sought to determine whether this method is suitable for widespread use. METHODS: A group of 19 operators including 11 trainees in three pacing centres attempted to use cephalic access alone for all CRT device implants over a period of 8 years. The access route for each lead, the procedure outcome, duration, and complications were collected prospectively. Data were also collected for 105 consecutive CRT device implants performed by experienced operators not using the exclusively cephalic method. RESULTS: A new implantation of a CRT device using exclusively cephalic venous access was attempted in 1091 patients (73.6% male, aged 73 ± 12 years). Implantation was achieved using cephalic venous access alone in 801 cases (73.4%) and using a combination of cephalic and other access in a further 180 (16.5%). Cephalic access was used for 2468 of 3132 leads implanted (78.8%). Compared to a non-cephalic reference group, complications occurred less frequently (69/1091 vs 12/105; P = .0468), and there were no pneumothoraces with cephalic implants. Procedure and fluoroscopy duration were shorter (procedure duration 118 ± 45 vs 144 ± 39 minutes, P

Introduction Although catheter ablation therapy is a well-established treatment for cardiac dysrhythmias, the success rates for longstanding, persistent AF with dilated atria remain unsatisfactory. The minimally invasive hybrid technology is a novel form of therapy. Methods A prospective, single-center UK study to evaluate the hybrid ablation technique for patients with longstanding (>1 year) persistent AF and dilated atria. Stage 1 was a minimally invasive epicardial approach for ablation of the posterior wall of left atrium (LA) and pulmonary veins (PVs). Stage 2 was a transcatheter approach via the femoral veins to isolate the endocardial aspect of the PVs +/− posterior wall. Occasionally, the sequence of the stages was reversed. Results Forty-one patients were enrolled for the study with a mean follow-up for 16±9 months. Mean age was 65±9 years and the mean BMI was 32±7. Males constituted 75% of the study cohort. Mean LA size was 48±7 mm and mean left ventricular ejection fraction (LVEF) was 51.9%, although 51.6% of patients had impaired LVSF (LVEF below 55%). 87.8% CI (0.7–0.9) of patients remained in sinus rhythm (SR) without repeat ablation, whereas only 12.2% CI (0.04–0.02) had redeveloped persistent AF. Although numerically different, there was no statistically significant difference in maintaining SR between patients with severely dilated LA (>50 mm) and those without (70% vs. 90%, respectively; z=−1.39, p=0.165). Major perioperative complications during stage 1 ablation were low, with IVC injury in 1 patient and a mild stroke in 1 patient. Median LOS was 1 day (1–4 days) and there was no 30-day mortality after stage 1. Conclusions The hybrid ablation therapy has a conversion rate from longstanding persistent AF to SR of 87.8% at a mean follow-up of 16±9 months, without repeat ablation. LOS was short, with very few complications and no peri-operative mortality. The hybrid approach appears to be very encouraging for a condition with otherwise low success rates by conventional endocardial techniques alone. Funding Acknowledgement Type of funding source: None

Background Atrio-oesophageal fistula formation accounts for the majority of AF ablation-related morbidity and mortality. Thermal injury to the oesophagus can be significantly reduced by application of oesophageal cooling for protection during AF ablation. The effect of this method of oesophageal protection in patients receiving radiofrequency (RF) ablation guided by Ablation Index technology is currently unknown. Objective To investigate the ability of a temperature control device to protect the oesophagus from ablation-related thermal injury in patients receiving AF ablation guided by Ablation Index technology. Methods The IMPACT study is a single-centre, prospective, double-blind randomized controlled trial, which investigated the ability of a controlled method of oesophageal cooling to protect the oesophagus from ablation-related thermal injury. The EnsoETM device was used to deliver oesophageal cooling. This method was compared in a 1:1 randomization to a control group of standard practice utilizing a single-sensor temperature probe. In the study group, the device was used to keep the luminal temperature at 4°C during RF ablation. All participants received AF ablation using Ablation Index technology at posterior and anterior settings (30W at 350–400 and 40W at 450–500, respectively). Endoscopic examination was performed within 7 days post-ablation and oesophageal injury was graded. The patient and the endoscopist were blinded to the randomization. Structured clinical follow up occurred after 3 months post-ablation; both patient and follow up clinician were blinded. Results We recruited 188 patients, of whom 120 underwent endoscopic evaluation. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 versus 2/60; P=0.008). There was no difference between groups in RF time, lesion duration, force, power and combined ablation index (P value range= 0.2–0.9). Procedure and fluoroscopy duration were similar (P=0.97, P=0.91 respectively). The majority of those who passed through the 1st follow up evaluation (n=136) did not have gastrointestinal or chest pain symptoms post ablation and there was no difference between the randomized groups. Only 4.4% overall had severe symptoms and they were poorly correlated against those who sustained mucosal lesions. AF recurrence was similar in both groups (8% vs 8.8%). There were 2 cases of vascular trauma needing intervention in the control group and 1 case of conservatively managed pericardial effusion in the protected group only. Clinical and endoscopy findings did not report any EnsoETM device-related trauma. Conclusion Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared to standard care when ablation is performed using radiofrequency with Ablation Index technology. This method of oesophageal protection is safe and does not compromise the efficacy of the ablation procedure. Endoscopy findings and patient symptoms. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): 1. Public hospital: St. George's NHS Foundation Trust; 2. Private company: Attune Medical (Chicago, IL)

Background Esophageal thermal injury can occur after radiofrequency (RF) ablation in the left atrium to treat atrial fibrillation. Existing methods to prevent esophageal injury have various limitations in deployment and uncertainty in efficacy. A new esophageal heat transfer device currently available for whole-body cooling or warming may offer an additional option to prevent esophageal injury. We sought to develop a mathematical model of this process to guide further studies and clinical investigations and compare results to real-world clinical data. Results The model predicts that the esophageal cooling device, even with body-temperature water flow (37 °C) provides a reduction in esophageal thermal injury compared to the case of the non-protected esophagus, with a non-linear direct relationship between lesion depth and the cooling water temperature. Ablation power and cooling water temperature have a significant influence on the peak temperature and the esophageal lesion depth, but even at high RF power up to 50 W, over durations up to 20 s, the cooling device can reduce thermal impact on the esophagus. The model concurs with recent clinical data showing an 83% reduction in transmural thermal injury when using typical operating parameters. Conclusions An esophageal cooling device appears effective for esophageal protection during atrial fibrillation, with model output supporting clinical data. Analysis of the impact of ablation power and heart wall dimensions suggests that cooling water temperature can be adjusted for specific ablation parameters to assure the desired myocardial tissue ablation while keeping the esophagus protected.

This letter to the editor concerns the article: 'Innovative tools for atrial fibrillation ablation' by Rottner et al., published in the journal on 13th of May 2020. We read the article with great interest and congratulate the authors on an impressively detailed summary of the current tools and technological advances in atrial fibrillation ablation. Improving the safety of this procedure is very important due to widespread clinical practice and the increasing demand for this procedure. We would like to share further discussion with the authors and the journal's readership on current advances in improving the safety of this procedure - esophageal cooling. The results of a large randomized trial was recently presented, the IMPACT study (NCT03819946), which showed that a simple, standardized method of esophageal cooling with the ensoETM® device can significantly reduce esophageal thermal injury by 83.4%. Esophageal protection is important as esophageal injury has a high mortality rate to those that sustain this injury although the overall incidence is low. Rottner et al. discuss a much smaller study on esophageal cooling and the limitations of this study are also discussed.

Aims Several large studies have documented the outcome of transvenous lead extraction (TLE), focusing on laser and mechanical methods. To date there has been no large series addressing the results obtained with rotational lead extraction tools. This retrospective multicentre study was designed to investigate the outcomes of mechanical and rotational techniques. Methods and results Data were collected on a total of 2205 patients (age 66.0 ± 15.7 years) with 3849 leads targeted for extraction in six European lead extraction centres. The commonest indication was infection (46%). The targeted leads included 2879 pacemaker leads (74.8%), 949 implantable cardioverter-defibrillator leads (24.6%), and 21 leads for which details were unknown; 46.6% of leads were passive fixation leads. The median lead dwell time was 74 months [interquartile range (IQR) 41–112]. Clinical success was obtained in 97.0% of procedures, and complete extraction was achieved for 96.5% of leads. Major complications occurred in 22/2205 procedures (1%), with a peri-operative or procedure-related mortality rate of 4/2205 (0.18%). Minor complications occurred in 3.1% of procedures. A total of 1552 leads (in 992 patients) with a median dwell time of 106 months (IQR 66–145) were extracted using the Evolution rotational TLE tool. In this subgroup, complete success was obtained for 95.2% of leads with a procedural mortality rate of 0.4%. Conclusion Patient outcomes in the PROMET study compare favourably with other large TLE trials, underlining the capability of rotational TLE tools and techniques to match laser methods in efficacy and surpass them in safety.