Introduction. During left bundle branch area pacing (LBBAP) lead implantation, intermittent monitoring of unipolar pacing characteristics validates LBB capture and can detect septal perforation. We aimed to demonstrate that continuous uninterrupted unipolar pacing from an inserted lead stylet (LS) is feasible and facilitates LBBAP implantation. Methods. Thirty patients (mean age 76 ± 14 years) were implanted with stylet-driven pacing lead (Biotronik Solia S60). In 10 patients (validation-group) conventional, interrupted implantation was performed, with comparison of unipolar pacing characteristics between LS and connector-pin (CP)-pacing after each rotation step. In 20 patients (feasibility-group) performance and safety of uninterrupted implantation during continuous pacing from the LS were analyzed. Results. In the validation-group, LS and CP-pacing impedances were highly correlated (R2=0.95, p<0.0001, bias 12±37Ω). Pacing characteristics from LS and CP showed comparable sensed electrograms and paced QRS morphologies. In the feasibility-group, continuous LS-pacing allowed beat-to-beat monitoring of impedance and QRS morphology to guide implantation. This resulted in successful LBBAP in all patients, after a mean of 1±0 attempts, with mean threshold 0.81 ± 0.4V, median sensing 6.5mV [IQR 4.4-9.5] and mean impedance 624 ± 101Ω, and positive LBBAP-criteria with median paced QRS duration 120ms [IQR 112-152ms] and median pLVAT 73ms [IQR 68-80.5ms]. No septal perforation occurred. Conclusion. Unipolar pacing from the LS allows accurate determination of pacing impedance and generates similar paced QRS morphologies and equal sensed electrograms, compared to CP pacing. Continuous LS pacing allows real-time monitoring of impedance and paced QRS morphology, which facilitates a safe and successful LBBAP lead implantation.

Introduction The reuse of cardiac implantable electronic devices may help increase access to these therapies in low- and middle-income countries (LMICs). No published data exist regarding the views of patients and family members in LMICs regarding this practice. Methods and Results A paper questionnaire eliciting attitudes regarding pacemaker reuse was administered to ambulatory adult patients and patients’ family members at outpatient clinics at Centro Nacional Cardiologia in Managua, Nicaragua, Indus Hospital in Karachi, Pakistan, Hospital Carlos Andrade Marín and Hospital Eugenio Espejo in Quito, Ecuador, and American University of Beirut Medical Center in Beirut, Lebanon. There were 945 responses (Nicaragua – 100; Pakistan – 493; Ecuador – 252; Lebanon – 100). A majority of respondents agreed or strongly agreed that they would be willing to accept a reused pacemaker if risks were similar to a new device (707, 75%), if there were a higher risk of device failure compared to a new device (584, 70%), or if there were a higher risk of infection compared to a new device (458, 56%). A large majority would be willing to donate their own pacemaker at the time of their death (884, 96%) or the device of a family member (805, 93%). Respondents who were unable to afford a new device were more likely to be willing to accept a reused device (79% vs. 63%, P<0.001). Conclusions Patients and their family members support the concept of pacemaker reuse for patients who cannot afford new devices.

vHPvSD ablation represents a quantum leap from the RF settings that have traditionally been used in electrophysiology. If used to its full potential, it may improve procedural efficiency by reducing ablation and procedure times. However, with great power comes great responsibility; we need to ensure that we use it judiciously and safely.

Introduction: Early recurrence (ER) of atrial fibrillation (AF) is defined as the recurrence of atrial tachyarrhythmias within 3 months after AF ablation, however, this definition is based on data from the era of radiofrequency catheter ablation (RFCA), without contact force (CF) technology. We investigated the significance of ER as a risk factor for late recurrence (LR) in paroxysmal AF (PAF) patients treated with CF and non-CF-guided ablation. Methods and Results: We studied 395 patients with PAF who underwent RFCA. Of these, 97 patients underwent RFCA without CF technology (Non-CF group) and 298 underwent with CF technology (CF group). Over a 2-year post-ablation follow-up period, LR occurred in 54 of 97 (55.7%) patients in the Non-CF group, and in 105 of 298 (35.2%) patients in the CF group. ER had a more significant relationship with LR in the CF than in the Non-CF group, and all patients in the CF group with ER in the 3rd month developed LR. Conclusion: ER in PAF patients who have undergone CF-guided ablation have a greater risk of LR than those who have undergone non-CF-guided ablation. ER in the 3rd month after CF-guided ablation may indicate an absolute risk of LR. Blanking period could be defined as 2 months in the CF era.

Background: Transvenous permanent pacemaker related infection is a severe condition associated with significant morbidity and mortality. Leadless pacemakers may be more resistant to bacterial seeding during bloodstream infection because of its small surface area and encapsulation in the right ventricle. This study reports the incidence and outcomes of bacteraemia in patients implanted with a Micra leadless pacemaker. We present 18F-FDG PET/CT findings obtained in a sub-group of patients. Methods: We report a retrospective cohort study of 155 patients who underwent a Micra TPS implant procedure at the University Hospitals of Leuven between July 2015 and July 2019. We identified the patients who developed an episode of bacteraemia, proved by ≥2 positive blood cultures. Results: Of the 155 patients, 15 patients presented an episode of bacteraemia at a median of 226 days (range: 3-1129) days after the implant procedure. Gram positive species accounted for 73.3% (n=11) of the bacteraemia including Staphylococcus (n=5), Enterococcus (n=3) and Streptococcus (n=3). The source of infection was identified in 9 patients (60%) including endocarditis in 4 patients, urinary tract in 3 patients, and skin in 2 patients. 18F-FDG PET/CT imaging performed in 6 patients did not show sign of infection around the leadless pacemaker. Bacteraemia was resolved in all patients after adequate antibiotherapy. Four patients died early during follow up. For all other patients, there were no recurrence of bacteraemia during a median follow up of 263 days (range 15-1134). Conclusion: In our small cohort, no leadless pacemaker endocarditis was observed among patients with bacteraemia.

Introduction: Contact force (CF) catheters provide feedback confirming adequate tissue contact for optimal lesion size and minimal complications. CF ablation catheters have resulted in decreased procedure times and improved outcomes for ablation of atrial fibrillation in adults. There is limited data evaluating CF use for accessory pathway (AP) ablation or in pediatric patients. The aim of our study was to compare a cohort who underwent AP ablation with a CF catheter to historical controls, evaluating for differences in procedure times, number of lesions, and outcomes. Methods: A retrospective chart review of CF ablation cases at Children’s Wisconsin performed between June 2015 to April 2018 was compared to a historical control cohort of traditional radiofrequency (RF) ablations between June 2012 to June 2015. 43 patients with APs underwent 49 CF ablation procedures (18 males, 13.6 ± 3 years old) and a control cohort consisted of 77 procedures in 69 patients (38 males, 12.4 ± 4 years). Results: The groups did not differ significantly on procedure time (CF 2.01 ± 0.48 hr, control 1.53 ± 0.48 hr, p = 0.37), or total lesions administered (CF and control 7 ± 6 lesions, p = 0.89). CF cases showed a trend toward improvement in acute success (98% CF, 90% controls, p = 0.15) though with increased recurrence compared to controls (13% CF, 5% controls, p = 0.16), neither being statistically significant. Conclusion: Our study suggests that ablation outcomes using CF are comparable to traditional RF ablation in pediatric patients with APs.

Introduction Left bundle branch area pacing (LBBAP) aims to achieve physiological pacing by capturing the conduction system in the area of the left bundle branch. LBBAP has exclusively been performed using lumen-less pacing leads (LLL) with fixed helix design. This study explores the feasibility, safety and pacing characteristics of LBBAP using stylet-driven leads (SDL) with an extendable helix design. Methods Patients, in which LBBAP was attempted for bradycardia or heart failure pacing indications, were prospectively enrolled at the Ghent University Hospital. LBBAP was attempted with two different systems: 1/ LLL with fixed helix (SelectSecure 3830, Medtronic, Inc) delivered through a preshaped sheath (C315His Medtronic) and 2/ SDL with extendable helix (SoliaS60, Biotronik, SE & CO) delivered through a new delivery sheath (Selectra 3D, Biotronik). Results The study enrolled 50 patients (mean age 7014 years, 44% female). LBBAP with SDL was successful in 20/23 (87%) patients compared to 24/27 (89%) of patients in the LLL group (p=0.834). Screw attempts, screw implant depth, procedural and fluoroscopy times were comparable among both groups. Acute LBBAP thresholds were low and comparable between SDL and LLL (0.50.15V versus 0.40.17V, p=0.251). Pacing thresholds remained low at 32.1 months of follow up in both groups and no lead revisions were necessary. Post procedural echocardiography revealed a septal coronary artery fistula in one patient with SDL LBBAP. Conclusion LBBAP using stylet-driven pacing leads is feasible and yields comparable implant success to LBBAP with lumen-less pacing leads. LBBAP thresholds are low and comparable with both types of leads.

Background: Some long QT syndrome (LQTS) patients experience breakthrough cardiac events (BCEs) despite maximal therapy. Small studies have shown that intentional permanent atrial pacing (IPAP) is beneficial in refractory LQTS. As such, we sought to determine the genotype-specific utilization and efficacy of IPAP in a single-center LQTS registry. Methods and Results: In this retrospective study, electronic medical records from 1,065 LQTS patients were used to identify individuals that received IPAP. Pre- and post-IPAP heart rate, heart rate-corrected QT (QTc) values, annual BCE rate, and IPAP-related complications were compared between genotypes. BCEs were defined as LQTS-associated syncope/seizures, ventricular arrhythmia (VA)-terminating ICD therapies, and sudden cardiac arrest/death. Overall, 52/1065 LQTS patients received adjunctive IPAP therapy [77% female; median age 18.5 (IQR 1-35.5) years; 73% with prior VA]. Over an average IPAP follow-up of 121  82 months, the average heart rate increased from 65.8  20.4 bpm to 78.9  17.1 bpm; (p<0.01) and the average QTc decreased from 533.4  66.6 ms to 488.3  52.4 ms; (p<0.01). The mean BCE rate dropped from 0.88 to 0.19 per patient-year (p=0.01), driven by a marked decrease in LQT2 patients (1.01 BCE/year to 0.02 BCE/year; p=0.003). No serious IPAP-related complications were observed. Conclusion: In high-risk LQTS patients, namely those with recalcitrant LQT2, IPAP appears to be a safe and efficacious adjunct therapy. The beneficial effects of IPAP may stem from attenuating the QTc and circumventing a pause-dependent trigger. Whether IPAP might obviate the need for an ICD in some instances warrants further study.

Introduction Detail 3D mapping have been useful for effective radiofrequency catheter ablation. Rhythmia system can create the atrio-ventricular dual chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of Rhythmia system for catheter ablation of accessory pathways (AP). Methods From July 2015 to August 2020, 111 patients underwent ablation of APs. The dual chamber mappings were created in 50 patients [median age 15 (10-54), 32 male(64.0%)], while 61 patients underwent the radiofrequency (RF) ablations with conventional single chamber 3D mappings. The background characteristics and procedure details were compared between the dual chamber mapping group and conventional single chamber mapping group. Results The number of RF application [1 (1-3) vs 3 (1-6), p=0.0023], RF time [9.2 (2.0-95.7) vs 95.6 (4.1-248.7), p=0.0023], RF energy [248.4 (58.7-3328.2) vs 2867.6 (134.2-7728.4), p=0.0115] were significantly lower in dual chamber group. Fluoroscopy time [19.9 (14.2-26.1) vs 26.5 (17.7-43.4), p=0.0025], and fluoroscopy dose [52.5 (31.3-146.0) vs 119.0 (43.7-213.5), p=0.0249] were also significantly lower than in single chamber mapping group. Conclusion The dual chamber mappings were useful for effective ablation with reducing the radiation exposure.

Background: It is established that ethanol infusion in the vein of Marshall (EIVOM) effectively creates a linear ablation lesion in the mitral isthmus (MI). However, data on the long-term success rates of MI ablation remains limited. Methods and Results: Our cohort consisted of 560 patients with non-paroxysmal atrial fibrillation (AF) who underwent an initial MI ablation. Ablations were performed by only radiofrequency (RF) in 384 patients (RF group) or by RF and EIVOM in 176 patients (EIVOM/RF group). Ethanol of 5 mL was used to perform EIVOM in advance of RF. Following EIVOM, RF pulses were delivered to the lateral MI line. Bidirectional MI block was fully achieved in 353 (first 318, re-do 35) patients of the RF group and 171 (first 128, re-do 43) patients of the EIVOM/RF group (p = 0.09 in the first, 0.10 in the re-do ablation cases). In cases with complete MI line block, recurrent AF or atrial tachycardia (AT) was observed in 130 (37%) patients of the RF group and in 64 (37%) patients of the EIVOM/RF group (log-rank p = 0.12 in the first, 0.30 in the re-do ablation cases). Of the total 194 patients, 112 with drug refractory AF or AT proceeded to the subsequent ablation process. Reconnection of MI block line was observed in 39 (49%) patients in the RF group and 25 (58%) patients in the EIVOM/RF group (p = 0.32). Conclusion: EIVOM effectively ensures MI line block; however, the reconnection rate was similar between the two groups.

Introduction: Ultra-high-density mapping for ventricular tachycardia (VT) is increasingly used. However, manual annotation of local abnormal ventricular activities (LAVAs) is challenging in this setting. Therefore, we assessed the accuracy of the automatic annotation of LAVAs with the Lumipoint algorithm of the Rhythmia system (Boston Scientific). Methods and Results: One hundred consecutive patients undergoing catheter ablation of scar-related VT were studied. Areas with LAVAs and ablation sites were manually annotated during the procedure and compared with automatically annotated areas using the Lumipoint features for detecting late potentials (LP), fragmented potentials (FP), and double potentials (DP). The accuracy of each automatic annotation feature was assessed by re-evaluating local potentials within automatically annotated areas. Automatically annotated areas matched with manually annotated areas in 64 cases (64%), identified an area with LAVAs missed during manual annotation in 15 cases (15%), and did not highlight areas identified with manual annotation in 18 cases (18%). Automatic FP annotation accurately detected LAVAs regardless of the cardiac rhythm or scar location; automatic LP annotation accurately detected LAVAs in sinus rhythm, but was affected by the scar location during ventricular pacing; automatic DP annotation was not affected by the mapping rhythm, but its accuracy was suboptimal when the scar was located on the right ventricle or epicardium. Conclusion: The Lumipoint algorithm was as/more accurate than manual annotation in 79% of patients. FP annotation detected LAVAs most accurately regardless of mapping rhythm and scar location. The accuracy of LP and DP annotations varied depending on mapping rhythm or scar location.

Background: Local impedance (LI) can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). However, data on the effects of catheter contact angle on LI parameters are scarce. This study aimed to evaluate the influence of catheter contact angle on LI changes and lesion size with 2 different LI-sensing catheters in a porcine experimental study. Methods: Lesions were created by the INTELLANAV MiFi™ OI (MiFi) and the INTELLANAV STABLEPOINT™ (STABLEPOINT). RFCA was performed with 30 watts and a duration of 30 seconds. The CF (0, 5, 10, 20, and 30 g) and catheter contact angle (30°, 45°, and 90°) were changed in each set (n=8 each). The LI rise, LI drop, and lesion size were evaluated. Results: The LI rise increased as CF increased. There was no angular dependence with the LI rise under all CFs in the MiFi. On the other hand, the LI rise at 90° was lower than at 30° under 5 and 10 g of CF in STABLEPOINT. The LI drop increased as CF increased. Regarding the difference in catheter contact angles, the LI drop at 90° was lower than that at 30° for both catheters. The maximum lesion widths and surface widths were smaller at 90° than at 30°, whereas there were no differences in lesion depths. Conclusion: The LI drop and lesion widths at 90° were significantly smaller than those at 30°, although the lesion depths were not different among the 3 angles for the MiFi and STABLEPOINT.

Background: Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small diameter, lumenless, catheter delivered, defibrillator lead was developed with the aim to improve long term reliability. Methods and Results: The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi-center, single-arm, Bayesian, adaptive design, pre-market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre-hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients will participate for a minimum of 18 months to approximately 3 years. Fracture-free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in-vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow-up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. Conclusion: The LEADR Clinical Study was designed to efficiently provide evidence for short- and long-term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach.

The pandemic caused by SARS-CoV-2 has affected communities throughout the world. The global nature of health care disparities is exacerbated by COVID-19. Patients in Low-and Middle-Income Countries have limited health care resources and marginal support for the evaluation and treatment of cardiac rhythm disorders. Heart Rhythm Societies and their members need to advocate for increased subsidies and assistance for these patients.

Introduction: Patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) require chronic anticoagulation due to a high thromboembolic risk. Evidence supporting use of non-vitamin K oral anticoagulants (NOACs) in patients with HCM remains sparse, and there are no data regarding the use of NOACs in HCM patients undergoing catheter ablation of AF. Methods: Observational non-randomised study in 4 European Centres. We aimed to investigate the safety and efficacy of NOACs compared with vitamin-K antagonists (VKAs) in patients with HCM undergoing catheter ablation for AF. Results: One hundred thirty-seven HCM patients (mean age 55.0±13.4, 29.1% female) underwent 230 catheter ablations for AF (1.7±1.0 per patient). A total of 55 patients (39.4%) underwent 70 procedures (30.4%) on NOAC, while the remaining were on VKA. Warfarin (97.6%) and rivaroxaban (56.4%) were the most frequently used agents in the respective groups. No procedure-related deaths were reported. We observed no significant difference in the rate of thromboembolism (VKA 0.6%; NOAC 0%; p=1.0) or minor bleeding (VKA 0.6%; NOAC 1.4%; p=0.54). There was a non-significant trend towards a lower incidence of major bleeding (VKA 6.8%; NOAC 1.4%; p=0.09). Conclusion: These preliminary data suggest that NOACs are at least as safe and effective as VKAs in patients with HCM undergoing catheter ablation for AF.

Introduction: Remote monitoring (RM) has profoundly transformed the standard of care for patients with cardiac electronic implantable devices. It provides easy access to valuable information about arrhythmic events, acute decompensation manifestations and device-related issues without the need of continuous in-person visits. Methods: Starting March 1st, 332 patients were introduced to a RM program during the Italian lockdown in order to limit the risk of in-hospital exposure to Severe Acute Respiratory Syndrome Coronavirus-2. Patients were categorized in two groups based on the modality of RM delivery [home (n=229) vs office (n= 103) delivered]. The study aimed at assessing the efficacy of the new follow-up protocol, reported as the mean RM Activation Time (AT) and the need for technical support for its activation. Patients’ acceptance and anxiety status was also quantified by means of the Home Monitoring Acceptance and Satisfaction Questionnaire and the Generalized Anxiety Disorder 7-item scale. Results: AT time was <48 hours in 93% of patients and 7% of them required further technical support. Despite a higher number of trans-telephonic technical support in home-delivered RM group, AT was comparable between groups (1.33±0.83 days in home-delivered vs 1.28±0.81 days in office-delivered patients; p=0.60). Twenty-eight (2.5%) urgent/emergent in-person examinations were planned. High degree of patient’s satisfaction was reached in both groups while anxiety status was higher in office-delivered group. Conclusions: RM was effective, safe and well tolerated by patients during the Italian lockdown. Our findings confirm the efficacy of this approach to reduce in-hospital visits, guaranteeing patients’ safety and quality of care.

Coronary artery injury is a rare complication of catheter ablation in the right ventricular outflow tract (RVOT). Furthermore, acute myocardial ischemia usually causes polymorphic ventricular tachycardia (VT) or ventricular fibrillation. We herein describe a case in which catheter ablation for VT originating from the RVOT provoked ischemia-related VTs due to acute occlusion of the left anterior descending artery.

Introduction: Elevated left atrial pressure (LAP) during catheter ablation of atrial fibrillation (AF) is associated with an increased risk of AF recurrence, but it is unknown if this correlates with heart failure (HF). The objective of the study was to determine if elevated LAP after AF ablation correlates with HF events. Methods: Prospective, single center, cohort study measuring LAP and RAP during AF ablation in 100 patients. The primary endpoint was clinical HF within 30 days of ablation. The secondary outcome was AF-free HF. Results: 100 patients (63% male, mean age 64.5) were enrolled and 20% had clinical HF within 30 days. Bivariate correlates included mitral valve (MV) disease, persistent AF, class III antiarrhythmics, LAP, and recurrent AF. Multivariate analysis revealed class III antiarrhythmics were protective (OR 0.24 [0.1–0.5], p=0.04), while MV disease (OR 8.7 [3.3—23], p=0.03) and loop diuretics (OR 4.8 [2.6–9.1], p=0.01) were hazardous. AF-free HF occurred in 9% of patients and correlated with higher LAP and RAP, and CKD. Conclusion: Patients with HF after AF ablation had higher LAP. MV disease, diuretic use, and class III antiarrhythmics also correlated to HF. These present opportunities to target future interventions to reduce a common complication of AF ablation.