Background Atrial tachyarrhythmias (ATAs) are common within the three-month blanking period following catheter ablation of atrial fibrillation (AF). However, little evidence is available regarding the current guidelines on the blanking period after surgical AF ablation. We investigate the incidence and significance of early recurrence of atrial tachyarrhythmia (ERAT) and evaluate the optimal blanking period after surgical AF ablation. Methods Data from 259 patients who underwent surgical AF ablation from 2009 to 2016 were collected. ERAT was defined as documented ATA episodes lasting for 30 seconds. A multivariate Cox proportional hazard model was constructed to evaluate the role of ERAT as a predictor of late recurrences (LR) for AF. Results In total, 127 patients (49.0%) experienced their last episodes of ERAT during the first (n=65), second (n=14), or third (n=48) month of the three-month blanking period (p<0.001). One-year freedom from ATAs was 97.8% in patients without ERAT compared with 95.4%, 64.3%, and 8.3% in patients with ERAT in the first, second, and third month after the index procedure, respectively (p<0.001). Hazard ratios of LR according to the timing of the last episode of ERAT first, second, and third month after the procedure were 2.84, 16.70, and 119.75, respectively. Conclusions The ERAT occurred in 49.0% of patients within the first three months after surgical ablation. The occurrence of ERAT within three months after surgical AF ablation was a significant independent predictor of LR. Hence, the currently accepted three-month blanking period needs to be redefined in patients with AF surgical ablation.

To the Editor,We have read with great interest the article entitled ‘Management of Patients with Interrupted Inferior Vena Cava Requiring Electrophysiology Procedures’ by Hanley et al1 in the latest issue of the journal. We would like to thank the authors for their difficult case series with interrupted vena cava inferior and for successfully performed electrophysiologic studies. Electrophysiologic procedures including mapping and percutaneous catheter ablation of left-sided accessory pathways via the retrograde transaortic approach have been successfully applied techniques in patients with supraventricular tachycardia with and without Wolff-Parkinson-White electrocardiographic pattern for a long time.2 If no anatomic obstacles are found, a deflectable mapping catheter can easily be advanced from the femoral artery and positioned in the mitral annulus to localize the accessory pathway, even in patients with congenital anomalies.3 One should keep in mind that the retrograde transaortic approach has the potential adverse events related to percutaneous arterial access and tight contact with valvular leaflets although it seems as a simpler and less time consuming approach requiring less specialized equipment compared to the transseptal way.Mapping and percutaneous catheter ablation of the atrioventricular node or the His bundle can also be performed from the left side via the retrograde transaortic approach. Some electrophysiologists prefer the retrograde transaortic route as a first-line approach although most operators perform catheter ablation from the venous side.The electrophysiologists’ preferences are generally based on experience, familiarity with the equipment and the procedure, and personal thoughts about the patient.Keywords: ablation; left-sided; retrograde transaortic approach

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.

None

This editorial will review the new pacing method described by the authors in this issue of the journal that they propose to ensure bi-directional cavo-tricuspid isthmus (CTI) conduction block after radiofrequency catheter ablation in patients with CTI dependent atrial flutter.

In 1999, Paul Myles et al. published an important paper outlining the details of a novel assessment tool to measure patients’ quality of recovery (QoR) post-anesthesia and surgery.[1] The following year, Paul Myles et al. published another article outlining the QoR-40. This study, as well as multiple other studies, further studied QoR-40’s validity, reliability, internal consistency, test-retest reliability, inter-rater reliability, and split-half coefficient.[1–3] It can be completed in a relatively short period (around five minutes).[3,4] However, its administration by the investigators provides more complete and timely data as compared to self-administration.[4] It has been translated into multiple languages and validated by these languages as well.[5] However, even though the QoR-40’s score has a maximum score of 200 with a range of 160, the minimal clinically important difference is only 4.8 units to translate into clinically relevant change. The difference between the mean QoR-40 scores post-cardiac surgery (with and without complications) was only four units while maintaining a wide standard deviation within groups.[5,6] QoR’s utility lies in its correlation with patient satisfaction as well as with another measure of patient well-being, the quality of life (QoL) score.[3] Furthermore, the QoR-40’s score three days post-cardiac surgery correlated well with the SF-36’s measure of QoL 3 months after the operation. Hence QoR-40 is helpful in assess patient’s short-term prognosis.[7] These findings hold even three years after the operation; however, the correlation level does decrease. [8]In this issue of the journal of cardiovascular electrophysiology, Wasserlauf et al. utilized the QoR-40 to measure the impact of the anesthesia used during cryoballoon ablation of paroxysmal atrial fibrillation.[9] Catheter ablation has become a common procedure for the management of paroxysmal atrial fibrillation with minor procedural complication. [10,11] Patients undergoing cryoballoon ablation for atrial fibrillation experience less pain than radiofrequency ablation. [12]Multiple sedative modalities can be utilized for cardiac catheter ablation. One modality is the use of a light anesthetic: It alerts the physician of patient discomfort, it comforts the physician and nursing staff and carries a lower risk of drug overdose. However, it does increase the patients’ intraoperative motion.[13] Other modalities include general anesthesia and deep sedation. However, it should be noted that conscious sedation does carry a risk of hypoventilation and aspiration. [14] In a previous study, no significant difference in complication rate was present following ventricular tachycardia ablation during minimal as compared to deep sedation. [15] Also, in another study, patients undergoing percutaneous epicardial access (for ventricular tachycardia or premature ventricular complex) had similar complication rates regardless of whether they did the procedure under general anesthesia or moderate/deep sedation. [16] Furthermore, in a study by Tang et al., patients who underwent non-conscious sedation during catheter ablation for atrial fibrillation had more transient anesthetic complications as compared to conscious sedation. However, these two groups did not reveal a difference in the procedure-related complication/success rates. [17] Finally, Wasserlauf et al. found moderate sedation to carry a lower procedure time without jeopardizing the complication and recurrence rate up to a median follow-up duration of 0.9 years. This paper studied patients undergoing cryoballoon ablation for paroxysmal atrial fibrillation. [18]Given the previously reported evidence supporting the use of conscious anesthesia during atrial fibrillation catheter ablation, Wasserlauf et al. set on a task to expand our knowledge of patients’ tolerance of moderate sedation during cryoballoon ablation. [9] Consequently, they studied patients undergoing cryoballoon ablation for paroxysmal atrial fibrillation under general anesthesia or moderate sedation. Within 24 hours after the procedure, patients would provide the QoR-40 and their likelihood to recommend the procedure and sedation method. The mean QoR-40 was greater than 180 in the two groups with a difference of less than 5 unites. Furthermore, the difference in the QoR-40 scores was not statistically significant. [9] These scores were better than scores observed by Myles in minor surgeries (178 ± 17) and cardiac surgeries without complications (176 ± 16). [6] Moreover, patients reported a high satisfaction rate with a high likelihood to recommend the procedures (83% and 89%) and a high likelihood to recommend the sedation method (94% and 85%) depending on the sedation method (general anesthesia and moderate sedation respectively). However, the difference was not statistically significant.[9] This result is similar to a previous study that found that 96% of patients would recommend radiofrequency ablation for atrial fibrillation.[19] What these results mean is that they support the use of moderate sedation as compared to general anesthesia, given the similar patient experience, but different procedure time, expense, and possible complications from general anesthesia. [9]This study, however, does have limitations. It was a single-center non-randomized study. The QoR-40 has sections that are heavily dependent on the medical center and staff; hence this is an important issue to consider. Furthermore, the assignment to anesthesia groups was not standardized, and the decision was dependent on physician and patient preference. Though understandable, the physician preference can be made to be dictated by a predefined set of criteria to minimize nonrandom assignment. Finally, we note that the QoR-40 scores presented by Wasserlauf et al. were the means and standard deviations. [9] When calculating the 95% confidence intervals of the difference of the mean QoR-40 scores of the two groups, we find that there is no statistically significant difference between the two groups.In conclusion, Wasserlauf et al. have added to our knowledge of cryoballoon ablation under moderate sedation which might become the more frequently adopted anesthesia strategy during AFib cryoablation.References:1. Myles PS, Hunt JO, Nightingale CE, et al. Development and psychometric testing of a quality of recovery score after general anesthesia and surgery in adults. Anesth Analg. 1999;88(1):83-90. doi:10.1097/00000539-199901000-000162. Myles PS, Weitkamp B, Jones K, Melick J, Hensen S. Validity and reliability of a postoperative quality of recovery score: The QoR-40. Br J Anaesth. 2000;84(1):11-15. doi:10.1093/oxfordjournals.bja.a0133663. Gornall BF, Myles PS, Smith CL, et al. Measurement of quality of recovery using the QoR-40: A quantitative systematic review. Br J Anaesth. 2013;111(2):161-169. doi:10.1093/bja/aet0144. Gower ST, Quigg CA, Hunt JO, Wallace SK, Myles PS. A comparison of patient self-administered and investigator-administered measurement of quality of recovery using the QoR-40. Anaesth Intensive Care. 2006;34(5):634-638. doi:10.1177/0310057x06034005145. Myles PS. Measuring quality of recovery in perioperative clinical trials. Curr Opin Anaesthesiol. 2018;31(4):396-401. doi:10.1097/ACO.00000000000006126. Myles PS. Clinically Important Difference in Quality of Recovery Scores. Anesth Analg. 2016;122(1):13-14. doi:10.1213/ANE.00000000000010607. Myles PS, Hunt JO, Fletcher H, Solly R, Woodward D, Kelly S. Relation between quality of recovery in hospital and quality of life at 3 months after cardiac surgery. Anesthesiology. 2001;95(4):862-867. doi:10.1097/00000542-200110000-000138. Myles PS, Viira D, Hunt JO. Quality of life at three years after cardiac surgery: Relationship with preoperative status and quality of recovery. Anaesth Intensive Care. 2006;34(2):176-183. doi:10.1177/0310057x06034002209. Wasserlauf, Jeremiah; Kaplan, Rachel; Walega, David; Arora, Rishi; Chicos, Alexandr; Kim, Susan; Lin, Albert; Verma, Nishant; Patil, Kaustubha; Knight, Bradley; Passman R. Patient-Reported Outcomes After Cryoballoon Ablation Are Equivalent Between Moderate Sedation And General Anesthesia. J Cardiovasc Electrophysiol. 2020.10. Chung MK, Refaat M, Shen WK, Kutyifa V, Cha YM, Di Biase L, Baranchuk A, Lampert R, Natale A, Fisher J, Lakkireddy DR. Atrial Fibrillation: JACC Council Perspectives. J Am Coll Cardiol. Apr 2020; 75 (14): 1689-1713.11. D’Avila A, Ptaszek LM, Yu PB, Walker JD, Wright C, Noseworthy PA, Myers A, Refaat M, Ruskin JN: Left Atrial-Esophageal Fistula After Pulmonary Vein Isolation. Circulation May 2007; 115(17): e432-3.12. Attanasio P, Huemer M, Shokor Parwani A, et al. Pain Reactions during Pulmonary Vein Isolation under Deep Sedation: Cryothermal versus Radiofrequency Ablation. PACE - Pacing Clin Electrophysiol. 2016;39(5):452-457. doi:10.1111/pace.1284013. Defaye P, Kane A, Jacon P, Mondesert B. Cryoballoon for pulmonary vein isolation: Is it better tolerated than radiofrequency? Retrospective study comparing the use of analgesia and sedation in both ablation techniques. Arch Cardiovasc Dis. 2010;103(6-7):388-393. doi:10.1016/j.acvd.2010.06.00414. Calkins H, Kuck KH, Cappato R, et al. 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design. Heart Rhythm. 2012;9(4):632-696.e21. doi:10.1016/j.hrthm.2011.12.01615. Wutzler A, Mueller A, Loehr L, et al. Minimal and deep sedation during ablation of ventricular tachycardia. Int J Cardiol. 2014;172(1):161-164. doi:10.1016/j.ijcard.2013.12.17516. Killu AM, Sugrue A, Munger TM, et al. Impact of sedation vs. general anaesthesia on percutaneous epicardial access safety and procedural outcomes. Europace. 2018;20(2):329-336. doi:10.1093/europace/euw31317. Tang RB, Dong JZ, Zhao W Du, et al. Unconscious sedation/analgesia with propofol versus conscious sedation with fentanyl/midazolam for catheter ablation of atrial fibrillation: A prospective, randomized study. Chin Med J (Engl). 2007;120(22):2036-2038. doi:10.1097/00029330-200711020-0001818. Wasserlauf J, Knight BP, Li Z, et al. Moderate Sedation Reduces Lab Time Compared to General Anesthesia during Cryoballoon Ablation for AF Without Compromising Safety or Long-Term Efficacy. PACE - Pacing Clin Electrophysiol. 2016;39(12):1359-1365. doi:10.1111/pace.1296119. Ezzat VA, Chew A, McCready JW, et al. Catheter ablation of atrial fibrillation - Patient satisfaction from a single-center UK experience. J Interv Card Electrophysiol. 2013;37(3):291-303. doi:10.1007/s10840-012-9763-5

Catheter ablation is the current standard of care for the management of symptomatic atrial fibrillation (AFib) refractory to pharmacological therapy. One of the complications of this procedure is thermal injury to the esophagus due to its anatomical proximity to the posterior wall of the left atrium (1). Rarely (<1%), an atrioesophageal fistula can form connecting the lumen of damaged esophagus to the atrial chamber (2). This complication is almost always fatal and can result in exsanguination, air embolism, and sepsis (3, 4). With a growing number of catheter ablations being performed each year, the rate of atrioesophageal fistulas is only expected to rise (5). Other more frequent complications include esophageal wall erosions and ulcers (47%), and thermal injury to the vagus nerve plexus leading to esophageal dysmotility and gastroparesis (17%) (6, 7). Therefore, protecting the esophagus from thermal injuries is paramount in ablative procedures and several strategies have been devised to help mitigate this risk. Many physicians monitor the luminal esophageal temperature (LET) [ as a surrogate for intramural esophageal tissue temperature] with a single sensor or multisensor temperature probe and interrupt energy delivery when LET reaches 38°C or 39°C during radiofrequency ablation. However, this technique significantly impacts the procedural workflow due to the waiting periods for LET to return to baseline. Alternative strategies involve cooling of the esophagus with ice water or reducing the ablation lesion power, contact force and/or duration but this strategy may increase the chances for pulmonary vein reconnection (8). To that end, there has been a growing interest in mechanical devices capable of deflecting the esophagus away from the atrium protecting it from thermal injury.In the current issue of the Journal of Cardiovascular Electrophysiology, Houmsse et al. introduce a novel device capable of mobilizing the esophagus laterally to protect it from injury when performing catheter ablation for AFib. Although other devices have been developed and/or used for this purpose (such as the transesophageal echocardiography probe, endotracheal stylet, Esosure stylet and DV8 shaped balloon retractor), this is the only one to operate using vacuum suction allowing it to latch onto the esophageal wall. The device consists of four main components: outer extrusion, inner stacking plates, deflecting arm and control handle. The outer extrusion is inserted via a trochanter or a bougie into the esophagus and is the only portion of the retractor that comes in contact with the surrounding tissues. Small perforations at the distal end allow for vacuum suction to adhere to the esophagus and for a radiocontrast agent to be delivered to delineate the esophageal contour. The inner stacking plates are then introduced through the outer extrusion and are designed to allow movement of the deflecting arm in the medio-lateral plane only. The deflecting arm is connected to the distal end of the stacking plates through a pivot point and can be steered using the control handle. The authors have evaluated the effectiveness and safety of the device on canine and swine animal models by measuring the distance and direction of displacement of the esophagus, examining the cellular architecture after prolonged suction, measuring the LET, and assessing compatibility of device with electroanatomical mapping systems. A total of 68 deviations were performed on four canine models. The average rightward deflection was equal to 26.6 ± 2.5mm compared to 18.7 ± 2.3mm for the direct leftward deflection (p<0.001), and 96% of deviations did not have an esophageal trailing edge. With the exception of one study, the average distance displaced using the suction retractor was superior to other devices (9-13). The substantial distance of deflection and the minimal esophageal trailing edge significantly decreased the rise in LET from baseline (mean increase of 0.2°C vs 2.5°C without deflection). Examination of the esophageal tissue integrity following one hour of continuous suctioning revealed no change in the esophageal cellular architecture, and only minimal circular areas of hyperemia in mucosa due to the suction ports without injury to the muscularis layer. Finally, the retractor did not interfere with the electroanatomical mapping systems used (CARTO and EnSite).Despite its interesting findings, this study has several limitations that should be acknowledged. First, the study was performed on swine and canine animal models, which are known to have an anatomy close to humans; however, the safety profile of the device and its effectiveness in displacing the esophagus may not translate in humans. Second, subjects may exhibit symptoms secondary to extreme deviation of the esophagus in the absence of distortion of the cellular architecture. Clinical studies are needed to assess the safety profile and side effects of this esophageal retractor. Third, it is unclear whether these results would be reproducible under monitored anesthesia care. Finally, the fluoroscopic equipment tools lacked electronic caliper capabilities, and the measurements were performed using radiopaque rulers.Overall, the authors should be commended on their efforts to introduce and evaluate an inexpensive and innovative tool for esophageal protection during AFib ablation. This retractor addresses the limitations of other products that serve a similar purpose. In fact, the suctioning power of the product minimizes the trailing edge of the esophagus that could not be managed with other devices which left esophageal tissue in the ablation field (10, 13). In addition, the control handle offers significant flexibility in device manipulation allowing physicians to choose the site of angulation and the angle of deflection depending on the patient’s anatomy. Future studies should focus on evaluating the safety and effectiveness of this device in humans. Given the growing number of esophageal retracting devices, studies should also aim to determine the device that produces the best esophageal protection and most desirable outcomes of ablation.REFERENCES1. Chung MK, Refaat M, Shen WK, Kutyifa V, Cha YM, Di Biase L, Baranchuk A, Lampert R, Natale A, Fisher J, Lakkireddy DR. Atrial Fibrillation: JACC Council Perspectives. J Am Coll Cardiol. Apr 2020; 75 (14): 1689-1713.2. D’Avila A, Ptaszek LM, Yu PB, Walker JD, Wright C, Noseworthy PA, Myers A, Refaat M, Ruskin JN. Left Atrial-Esophageal Fistula After Pulmonary Vein Isolation. Circulation May 2007; 115(17): e432-3.3. Aryana A, Arthur A, O’ Neill PG, D’Avila A. Catastrophic manifestations of air embolism in a patient with atrioesophageal fistula following minimally invasive surgical ablation of atrial fibrillation. Journal of cardiovascular electrophysiology. 2013;24(8):933-4.4. Stöckigt F, Schrickel JW, Andrié R, Lickfett L. Atrioesophageal fistula after cryoballoon pulmonary vein isolation. Journal of cardiovascular electrophysiology. 2012;23(11):1254-7.5. Oral H, Siontis KC. Prevention of Atrioesophageal Fistula After Catheter Ablation: If the Esophagus Cannot Stand the Heat (Cold), Can It Be Moved to the Sidelines? : JACC: Clinical Electrophysiology; 2017.6. Shah D, Dumonceau J-M, Burri H, Sunthorn H, Schroft A, Gentil-Baron P, et al. Acute pyloric spasm and gastric hypomotility: an extracardiac adverse effect of percutaneous radiofrequency ablation for atrial fibrillation. Journal of the American College of Cardiology. 2005;46(2):327-30.7. Schmidt M, Nölker G, Marschang H, Gutleben K-J, Schibgilla V, Rittger H, et al. Incidence of oesophageal wall injury post-pulmonary vein antrum isolation for treatment of patients with atrial fibrillation. Europace. 2008;10(2):205-9.8. Tran VN, Kusa S, Smietana J, Tsai W-C, Bhasin K, Teh A, et al. The relationship between oesophageal heating during left atrial posterior wall ablation and the durability of pulmonary vein isolation. Ep Europace. 2017;19(10):1664-9.9. Mateos JCP, Mateos EIP, Peña TGS, Lobo TJ, Mateos JCP, Vargas RNA, et al. Simplified method for esophagus protection during radiofrequency catheter ablation of atrial fibrillation-prospective study of 704 cases. Brazilian Journal of Cardiovascular Surgery. 2015;30(2):139-47.10. Bhardwaj R, Naniwadekar A, Whang W, Mittnacht AJ, Palaniswamy C, Koruth JS, et al. Esophageal Deviation During Atrial Fibrillation Ablation: Clinical Experience With a Dedicated Esophageal Balloon Retractor. JACC Clin Electrophysiol. 2018;4(8):1020-30.11. Herweg B, Johnson N, Postler G, Curtis AB, Barold SS, Ilercil A. Mechanical esophageal deflection during ablation of atrial fibrillation. Pacing and clinical electrophysiology. 2006;29(9):957-61.12. Palaniswamy C, Koruth JS, Mittnacht AJ, Miller MA, Choudry S, Bhardwaj R, et al. The extent of mechanical esophageal deviation to avoid esophageal heating during catheter ablation of atrial fibrillation. JACC: Clinical Electrophysiology. 2017;3(10):1146-54.13. Parikh V, Swarup V, Hantla J, Vuddanda V, Dar T, Yarlagadda B, et al. Feasibility, safety, and efficacy of a novel preshaped nitinol esophageal deviator to successfully deflect the esophagus and ablate left atrium without esophageal temperature rise during atrial fibrillation ablation: The DEFLECT GUT study. Heart Rhythm. 2018;15(9):1321-7.

To the Editor,We have read with great interest the article entitled ‘Electrogram-only guided approach to His bundle pacing with minimal fluoroscopy: A single-center experience’ by Zanon et al1 in the latest issue of the journal. We would like to thank the authors for their study regarding the use of electrograms during implantation of the His lead with minimal or no fluoroscopy. Related radiation dose parameters such as fluoroscopy time and dose area product (DAP) were also presented. Radiation dose related to the fluoroscopy system is generally dependent on various autoregulated variables including the tube voltage, the tube current and the pulse duration. In addition, various programmable settings including the frame rate, collimation, and magnification are used to regulate the amount of radiation although the number of variables which can be programmed in the manufacturer specific system varies. Fluoroscopy time should not be an estimation factor for radiation dose because its correlation with other standard radiation measures is weak. Manufacturer specific calculations, either total time while pressing on the fluoroscopy pedal or only a sum of fluoroscopic pulses, make the radiation dose difficult to estimate. The air kerma area product, or DAP (Gy.cm2) is accepted as the most accurate measurement of radiation energy given for fluoroscopic purposes. Roughly, the effective dose (ED) (mSv) of fluoroscopic source of radiation can be calculated using a conversion factor of 0.20 from the DAP measurement. For instance, routine single/dual-chamber pacemaker/defibrillator implantation has an average ED of 4 mSv, compared to an average ED of nearly 20 mSv for a cardiac resynchronization therapy device implantation.2 The frame rate, collimation and magnification should be properly set to reduce the DAP/ED values.The frame rate seems as the most important programmable factor related to the radiation dose. Continuous fluoroscopy has generally the frame rate of ≥30 frames per second (fps), which is associated with increased radiation exposure. Therefore, the frame rate should be set as low as achievable. Decreasing the frame rate from 30 fps to 7.5 fps reduces the ED by 75%. Compensatory tube current increase generally occurs during pulsed fluoroscopy, which is associated with the same number of x-rays produced during continuous fluoroscopy. However, significantly decreased number of pulses cause significant reduction of radiation exposure in a linear way. The frame rates as low as ≤3 fps should be used during diagnostic and ablation procedures and device implantations in the electrophysiology laboratory although reduced temporal resolution.2,3 Furthermore, configuring the frame rate ≤1 fps using the ECG triggering or pacing artifact can be the best approach. Configuration of the pulsed fluoroscopy at the lowest frame rate needed has the greatest potential for ensuring radiation dose at the lowest level.Properly configured and applied collimation, reduction of radiation to an anatomical area that requires imaging, has an important role in reducing both the direct and the scattered radiation. Collimation, especially the asymmetric one, reduces visualization area and decreases the DAP/ED in a linear way. During the procedure, the use of collimation restricts the view on the cardiac contour. After viewing the whole anatomy, re-collimation should be performed.Another option for reducing the radiation dose is to set the largest field of view, or the smallest magnification, possible. In the smallest field of view mode, or the largest magnification mode, a smaller radiation area is projected in the image intensifier and, a larger image is produced on the screen. This process is related to a lower radiation output and a dimmer image. The fluoroscopy unit has an automatic system for controlling the brightness sensed. Therefore, the automatic system compensates for the lower brightness by increasing radiation exposure from the tube. With the use of magnification, the radiation dose increase in flat-panel detectors is lower compared to the image-intensifiers, however it is still remarkable.4In the light of all above-mentioned settings, the fluoroscopy time should not be used as an important variable measuring the radiation dose. Instead, the DAP/ED values should be reported.Keywords: dose area product/effective dose; fluoroscopy; programmable; radiation dose

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：LAmbre occluder (Lifetech Scientific, Shenzhen, China), a new device for left atrial appendage (LAA) occlusion, is increasingly used, but the procedure for retrieval after dislodgement has rarely reported in human. Methods and Results：An 80-year-old male patient with permanent atrial fibrillation underwent the implantation of LAA occlusion device. The occluder dislodged to left atrium (LA) at the end of procedure. We failed to retrieve device in LA with a LASSO catheter and forceps with the 8.5F sheath. After it suddenly flowing into aortic arch, we successfully retrieved with a 14F flexible sheath and forceps. We also discussed reasons for the device dislodgment and reported experiences for device retrieval. Conclusion: Combination of the 14F flexible sheath and forceps could be used to retrieve the dislocation of LAA occlusion device.

Near-field Signals Detected by a Standard Bipolar Electrode without Detection of Corresponding Signals by Microelectrode: What is the Mechanism?Short title ; Near-filed Microelectrode signalTakashi Nakashima, MD*, Cyril Goujeau, MD, Yosuke Nakatani, MD,Ghassen Cheniti, MD, Pierre Jaïs, MD, Frédéric Sacher, MDAll authors have no conflicts of interest to disclose.Department of Cardiac Electrophysiology, Service de Rhythmologie, Hôpital Cardiologique du Haut-Lévêque (Centre Hospitalier Universtaire de Bordeaux)Avenue de Magellan, 33604, Bordeaux-Pessac, FranceCorrespondence to Takashi Nakashima, MDDepartment of Cardiac Electrophysiology, Service de Rhythmologie, Hôpital Cardiologique du Haut-Lévêque (Centre Hospitalier Universtaire de Bordeaux)Avenue de Magellan, 33604, Bordeaux-Pessac, FranceTel: +33 5 57 65 68 63 19, Fax: +33 5 57 65 68 96 20, Email; [email protected], ORCID: 0000-0002-8538-9259Key words: Ablation; Electrogram analysis; Microelectrode; Ventricular tachycardia

We read with great interest the recent study by Rogers, et al. describing lesion formation with continuous versus intermittent radiofrequency ablation.1 The authors applied 50 (ex-vivo) or 10 (in-vivo) watts with either intermittent (15-seconds x4, 30-seconds x2, or 60-seconds x1) or continuous (1, 2, 3, or 5 minutes) radiofrequency applications and examined lesion size with each strategy. Continuous lesions resulted in significantly larger lesion size with possibly increased risk of steam pops at high power. In the ex-vivo model, they saw rapid lesion formation in the first minute of ablation with substantial drop-off in expansion of lesion size over time especially after 3 minutes (down to 0.35mm/min at 5 minutes), and suggest that there is only minimal incremental benefit of prolonging ablation lesion duration beyond 3 minutes in normal tissue.They have, however, appropriately recognized the limitation of their model which lacks significant fibrosis, limiting the generalizability of their findings to ablation in patients with scar. It is important to recognize that lesion formation in scar-related ventricular tachycardia (VT) is likely to differ dramatically compared to normal myocardial tissue. Barkargan, et al. have shown in an in-vivo porcine model of anterior myocardial infarction that lesion formation in normal versus scar tissue can be substantially different.2Specifically, ablation lesions in scar tissue were histologically quite heterogeneous, and connective tissue tended to be more resistant to thermal injury than normal myocardium.We have seen many cases where after identifying critical VT circuit components with activation and entrainment mapping, VT slowing and termination could only be achieved very late (4-5 minutes) into radiofrequency application, suggesting continued lesion expansion due to delayed effect of conductive heating in scar tissue can persist well beyond 3 minutes. Historical data from Nath, et al. have demonstrated that tissue temperature of >50°C must be reached in order to achieve nonreversible cellular damage.3 In the setting of dense scar, as in patients with healed myocardial infarction or dense basal septal scar in nonischemic cardiomyopathy, dynamics of tissue heating and lesion formation are likely quite different than in normal tissue. Especially in intramural substrates which are “protected” by dense subendocardial (or subepicardial if ablating from the epicardium) scar, ablation with very long (>3 minute) lesions may have a more pronounced effect than in normal tissue. While in our experience, steam pops seem to occur less frequently when ablating in dense scar- even with long, high power lesions, close monitoring of ablation parameters including catheter tip temperature and impedance remain necessary during ablation to assure continued safety to avoid char formation and steam pops.We enthusiastically applaud the authors for their valuable contribution to the literature. While chronic cardiomyopathy models are technically difficult to create and costly to maintain, additional studies examining lesion formation in dense scar would be extremely helpful to delineate optimal ablation strategies in patient with cardiomyopathy and difficult VT substrates. Our clinical experience with late VT termination and prevention of inducibility after 4-5 minute radiofrequency ablation lesions in areas of marked fibrosis would support such additional study.References:1. Rogers AJ, Borne RT, Ho G, Sauer WH, Wang PJ, Narayan SM, Zheng L, Nguyen DT. Continuous Ablation Improves Lesion Maturation Compared with Intermittent Ablation Strategies. J Cardiovasc Electrophysiol 2020.2. Barkagan M, Leshem E, Shapira-Daniels A, Sroubek J, Buxton AE, Saffitz JE, Anter E. Histopathological Characterization of Radiofrequency Ablation in Ventricular Scar Tissue. JACC Clin Electrophysiol 2019;5:920-931.3. Nath S, DiMarco JP, Gallop RG, McRury ID, Haines DE. Effects of dispersive electrode position and surface area on electrical parameters and temperature during radiofrequency catheter ablation. Am J Cardiol 1996;77:765-767.

Introduction: Brugada syndrome is associated with ventricular arrhythmia leading to sudden cardiac death. Risk stratification is challenging, as major arrhythmic events (MAE) are rare. We assessed the utility of drug challenge testing in Brugada syndrome by a systematic review and meta-analysis. Methods and results: We comprehensively searched the databases of MEDLINE and EMBASE from inception to May 2019. Included studies compared the incidence of MAE between spontaneous and drug challenge induced Type-1. Data were combined using the random-effects, generic inverse variance method, to calculate pooled incidence and odds ratio (OR). Mixed-effects Poisson regression was used to calculated incidence rate ratio (IRR). Eighteen studies from 2006 to 2018 were included (4,099 patients, mean follow-up 4.5 years). Pooled annual incidences of MAE in spontaneous, drug challenge induced (regardless of symptoms), asymptomatic drug challenge induced, and symptomatic drug challenge induced Type-1 were 23.8 (95% confidence interval [CI]: 19.8-27.8), 6.5 (95% CI: 3.9-9.1), 2.1 (95% CI: -0.3-4.4), and 19.6 (95% CI: 9.9-29.3) per 1,000 person-years respectively. The incidence of MAE between symptomatic drug challenge induced and asymptomatic spontaneous Type-1 was not statistically different (IRR=1.0, 95%CI: 0.6-1.7). The presence of ventricular tachyarrhythmia during drug challenge testing was a predictor of MAE (OR=3.73, 95% CI: 1.77-7.86, p=0.001). Conclusions: The incidence of MAE in drug challenge induced Type-1 in asymptomatic patients is low. The incidence of MAE between symptomatic drug challenge induced and asymptomatic spontaneous Type-1 was similar. Ventricular tachyarrhythmia during drug challenge testing could be a useful risk marker for MAE in Brugada syndrome.

Despite extreme and undeniable progress in the concept of implantable cardioverter defibrillator (ICD) therapy over the last 40 years, the endocardial lead is still the weakest link of the system. Many efforts have been taken to improve the construction and consequently the durability of the lead. Not all of them were successful and some of the lead models proved to be technically imperfect, resulting in formal recalls. Similarly, patient- and procedure-related factors may strongly affect the lead reliability. The implantation of cardiac electronic devices (CIED) is considered to be a quite common vascular intervention. Also, there are strongly established opinions of best procedural manners, including the most optimal methods of vascular access during the CIED implantations.In this issue of the Journal of Cardiovascular Electrophysiology, Barbhaiya et al. present an interesting retrospective analysis of 660 patients who underwent the ICD implantations in one center from 2011-2017. The goal of the study was to determine the risk factors for premature lead failure. Four implanted leads models were assessed: Biotronik Linox, Sprint Quattro, Durata and Endotak.The main findings include:The ICD lead implantation via cephalic access in multi-lead ICD systems may be a risk factor for premature ICD lead failure (p<0.001).The overall risk of premature ICD lead failure was similar for all the analyzed lead models.Concerns regarding the durability of Biotronik Linox were discussed and the study showed its equal reliability compared to the other leads.Neither age nor gender were the risk factors for premature lead failure.An optimal vascular access for the endocardial lead implantation was investigated in many studies.1-4 So far, cephalic vein cutdown (CVC) was considered to be the method of choice, with the lowest rate of possible complications.2,4,5 Meta-analysis performed by Benz et al. (30 000 patients, more than 50 000 leads) compared CVC and subclavian puncture (SP) and demonstrated lower risk of lead failure when CVC was adopted.2 Axillary vein puncture (AP), especially when ultrasonography-guided, is a feasible technique and significantly reduces the probability of subclavian crush syndrome.6-8 Unfortunately this method is not used by many operators. EHRA survey from 2013 showed that in more than 80% of participating centers, the preferred method for venous access was either CVC or SP.9 What is worth emphasizing, in the study of Barbhaiya et al., axillary access was most often used for lead insertion – 76.8% (61-88%, dependently on the lead model). This fact may potentially explain the main study finding. It is also consistent with the interesting results of the PAIDLESS study presented in the paper of Shaikh et al.3 They showed that experienced operators preferably choose subclavian and/or axillary access (62% of implants), whereas low-volume implanters generally use cephalic vein approach (63%). High-volume operators are also less likely to experience lead failure.An important issue to discuss is the number of leads inserted via cephalic vein. The routine practice, also applied by Barbhaiya and colleagues, includes the placing of atrial and right ventricular leads via cephalic access, if possible. Inserting one or two leads is usually not a problem. There are many inventive ways for doing this, described in literature. Some operators go even further – they use cephalic vein to implant all three leads of cardiac resynchronization therapy (CRT) systems with the success rate of 87.7% - 91.7%.10,11The question of long-term reliability of the leads implanted in such a way is still open. They are tightly packed in one small vessel and possible lead - lead interaction may contribute to their failure. Especially the ICD leads, by definition more complex and sensitive, are prone to damage in these circumstances.Another possible locus minoris resistentiae is the site of cephalic vein ligation after the lead insertion. The line between an adequate and too strong suture tightening is quite narrow. The effort to stop the bleeding from the vein may cause ligation-induced lead insulation damage. Recently, Kajiyama et al. proposed a novel technique for the ligation of the cephalic vein during a two-in-one insertion of the leads.12 It reduces hemorrhaging without decreasing the lead safety.The discussion about the benefits of different vascular access should include the potential disadvantages of future lead extraction, especially in the multi-lead systems. Inserting more than one lead via cephalic vein may determine more problematic transvenous lead extraction procedure (TLE). It may also necessitate the extraction of the functioning lead because of its periprocedural damage during the TLE of the initially targeted lead.The reliability of ICD leads is certainly the most important feature. During the last decades several lead models produced by different manufacturers were recalled because of their serious technical defects. Numerous concerns and divergent literature data regarding the durability of the Linox lead were the premise for the authors to conduct the discussed study. An important observation is that all analyzed lead models, including Linox, were similar in terms of performance (p=0.769).Young and physically active patients were traditionally believed to have a higher risk of lead damage because of the intensive mechanical interaction between the lead and anatomical structures of costoclavicular space. This observation was not confirmed by the authors of the commented paper.The study has several limitations and they are all listed by the authors. The lack of multivariate risk factors analysis is the most important drawback. It could not be performed due to the low overall event rate. All interesting study findings require validation and further investigation.As the ICD lead failure is still a serious problem, the study investigating possible risk factors is always of great importance. With all the limitations, the paper presented by Barbhaiya et al. may be an important guide in dealing with the vascular access during CIED implantations. It sheds new light on the dogma of superiority of cephalic access. What is particularly important in the study outcome and what I personally find a very strong recommendation – is the conclusion that the multiple lead systems should be avoided, if not indicated, especially when combined with cephalic venous access. One possible solution is to use cephalic vein for one lead only. Prospective randomized studies directly comparing axillary and cephalic access would be highly desirable in order to come closer to the idea of the best vascular approach for the endocardial lead implantation.1. Knight BP, Curlett K, Oral H, Pelosi F, Morady F, Strickberger SA. Clinical predictors of successful cephalic vein access for implantation of endocardial leads. J Interv Card Electrophysiol.2002;7(2):177-180.2. Benz AP, Vamos M, Erath JW, Hohnloser SH. Cephalic vs. subclavian lead implantation in cardiac implantable electronic devices: a systematic review and meta-analysis. Europace.2019;21(1):121-129.3. Shaikh ZA, Chung JA, Kersten DJ, et al. Differences in Approaches and Outcomes of Defibrillator Lead Implants Between High-Volume and Low-Volume Operators: Results From the Pacemaker and Implantable Defibrillator Leads Survival Study (”PAIDLESS”). J Invasive Cardiol. 2017;29(12):E184-E189.4. Chan NY, Kwong NP, Cheong AP. Venous access and long-term pacemaker lead failure: comparing contrast-guided axillary vein puncture with subclavian puncture and cephalic cutdown. Europace.2017;19(7):1193-1197.5. Gallik DM, Ben-Zur UM, Gross JN, Furman S. Lead fracture in cephalic versus subclavian approach with transvenous implantable cardioverter defibrillator systems. Pacing Clin Electrophysiol.1996;19(7):1089-1094.6. Belott P. How to access the axillary vein. Heart Rhythm.2006;3(3):366-369.7. Liccardo M, Nocerino P, Gaia S, Ciardiello C. Efficacy of ultrasound-guided axillary/subclavian venous approaches for pacemaker and defibrillator lead implantation: a randomized study. J Interv Card Electrophysiol. 2018;51(2):153-160.8. Squara F, Tomi J, Scarlatti D, Theodore G, Moceri P, Ferrari E. Self-taught axillary vein access without venography for pacemaker implantation: prospective randomized comparison with the cephalic vein access. Europace. 2017;19(12):2001-2006.9. Bongiorni MG, Proclemer A, Dobreanu D, et al. Preferred tools and techniques for implantation of cardiac electronic devices in Europe: results of the European Heart Rhythm Association survey.Europace. 2013;15(11):1664-1668.10. Vogler J, Geisler A, Gosau N, et al. Triple lead cephalic versus subclavian vein approach in cardiac resynchronization therapy device implantation. Sci Rep. 2018;8(1):17709.11. Hadjis A, Proietti R, Essebag V. Implantation of cardiac resynchronization therapy devices using three leads by cephalic vein dissection approach. Europace. 2017;19(9):1514-1520.12. Kajiyama T, Ueda M, Ishimura M, et al. A novel technique for ligation of the cephalic vein reduces hemorrhaging during a two-in-one insertion of dual cardiac device leads. Indian Pacing Electrophysiol J. 2018;18(4):152-154.

Editorial commentary for “Electrogram Morphology Discriminators in Implantable Cardioverter Defibrillators: a comparative evaluation”.

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: The clinical efficacy and safety of hot balloon ablation (HBA) for treatment of persistent AF (PerAF) remain unclear. We aimed to evaluate the clinical efficacy and safety of HBA vs. cryoballoon ablation (CBA) as treatment for PerAF. Methods: Of 195 consecutive patients who underwent initial catheter ablation for PerAF (AF lasting >7 days but <12 months), 158 propensity score-matched (79 HBA and 79 CBA) patients were included in our study. All patients who underwent HBA received applications of energy to the upper posterior LA wall with a larger balloon in addition to single shots to each pulmonary vein (PV) ostium, whereas those who underwent CBA received simple single-shot applications. The electrically isolated surface area (ISA), including the PV antrum and part of the posterior LA wall, was assessed by high-resolution mapping. Results: Success of the PV isolation with balloon shots alone did not differ between HBA and CBA (81% vs. 85%; P = 0.52). The ISA was generally wide in both groups and significantly larger in the HBA group than in the CBA group (61 ± 16% vs. 51 ± 12%, P < 0.001). The incidence of procedure-related complications did not differ significantly (HBA 4% vs. CBA 1%; P = 0.62) nor did the arrhythmia recurrence rate (HBA 11% vs. CBA 18% at 18 months; P = 0.26). Conclusion: Despite the difference in protocols, HBA and CBA performed for PerAF appear comparable in terms of wide antral lesion creation, clinical efficacy, and safety.

Background: Atrial conduction velocity may represent atrial fibrillation (AF) substrate after pulmonary vein isolation (PVI). To elucidate the association between whole left atrial conduction velocity (LACV) and AF recurrence after PVI. Methods and Results: This observational study enrolled 279 patients who underwent PVI alone as an initial AF ablation procedure. After PVI, the left atrium was mapped with a 20-pole multielectrode in conjunction with the CARTO3 system during 100-ppm right atrial pacing. Left atrial conduction distance and conduction time were calculated from the start to the end of the propagation wave front in the left atrium. LACVs on the anterior and posterior routes were calculated as conduction distance divided by conduction time. Anterior and posterior LACVs were slower in patients with AF recurrence than in those without (anterior, 0.79 [0.71, 0.86] vs. 0.96 [0.90, 1.06], p < 0.001; posterior, 0.99 [0.89, 1.14] vs. 1.10 [1.00, 1.29], p < 0.001). AF recurrence was best predicted by anterior LACV with a cut-off value of 0.87 m/s (sensitivity 87%, specificity 81%, and predictive accuracy 84%). Multivariate analysis demonstrated that a slow anterior LACV < 0.87 m/s was an independent predictor of AF recurrence with an adjusted hazard ratio of 11.8 (6.36 – 22.0). Patients with anterior low-voltage areas demonstrated slower anterior LACV than those without low-voltage areas (0.89 [0.71, 1.00] vs. 0.94 [0.87, 1.05], p < 0.001). Conclusion: A slow LACV in the entire left atrium was an excellent predictor of AF recurrence after PVI, suggesting the necessity of additional ablations.