Atypical Atrial Flutter Ablation: The Clinical Impact of High-Density MappingBahjat Z. Ghazzal MD1, Marwan M. Refaat, MD21 Division of Cardiology, Department of Internal Medicine, University of Massachusetts Chan Medical School , Worcester, Massachusetts, USA2 Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, LebanonRunning Title: Atypical Atrial Flutter Ablation: The Clinical Impact of High-Density MappingWords: 700 (excluding the title page and references)Keywords: cardiac arrhythmias, heart diseases, cardiovascular diseases, catheter ablation, atrial flutter, high density mappingFunding: NoneDisclosures: NoneCorresponding Author:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCPTenured Professor of MedicineTenured Professor of Biochemistry and Molecular GeneticsMember, Division of Cardiology/ Section of Cardiac ElectrophysiologyDirector, Cardiovascular Fellowship Program American University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonUS Address: 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USAOffice: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)Atypical atrial flutter (AAFL) is an arrhythmia that is distinct from typical atrial flutter (AFL) due to its non-isthmus-dependent reentrant circuit, and often arises in patients with a history of cardiac surgery or ablation, where the resulting iatrogenic scar provides the basis for re-entry circuits.1 Catheter ablation for AAFL is an effective treatment option, associated with lower rates of thromboembolic events, transfusions, and shorter hospital stays compared to typical AFL.2 However, the complexity of AAFL circuits requires precise mapping, and traditional techniques often lack the resolution to accurately delineate these pathways. High-density (HD) mapping technology has emerged as a significant advancement in this regard, offering detailed electroanatomic maps that enhance procedural success.3 In this issue of the Journal of Cardiovascular Electrophysiology, the study by Sink et al. investigates the impact of HD mapping on AAFL ablation outcomes and healthcare utilization, providing valuable insights into its clinical benefits.4In this retrospective analysis, Sink et al. examined 108 patients who underwent AAFL ablation at a single academic center from 2005 to 2022. The cohort was divided into two groups: those who received HD mapping with a 16-electrode HD Grid catheter and Precision mapping system, and those who underwent non-HD mapping using traditional spiral catheters and the Velocity system. Primary outcomes included procedural success, defined as non-inducibility of the arrhythmia after ablation, and AFL recurrence. Secondary outcomes included emergency department (ED) visits, hospitalizations, and overall healthcare utilization within one-year post-procedure. The study revealed that HD mapping significantly improved both the delineation of AAFL circuits (92.5% vs. 76%; p=0.014) and procedural success rates (91% vs. 71%; p=0.006). Additionally, patients in the HD mapping group experienced significantly fewer ED visits (aIRR 0.32; p=0.007) and hospitalizations (aIRR 0.32; p=0.004) for AF/AFL/HF within the first year. While there was a trend towards lower AFL recurrence in the HD mapping group (aHR 0.60; p=0.13), this difference did not reach statistical significance. This study highlights the significant advantages of HD mapping in AAFL ablation. The enhanced resolution provided by HD mapping allows for more precise identification and targeting of arrhythmogenic substrates, leading to improved clinical outcomes.Though this study was well-conducted, minor limitations must be noted. The study’s retrospective design and single-center setting introduce potential biases and limit the generalizability of the results. The non-randomized nature of the study also raises the possibility of selection bias. Furthermore, the higher use of contact force-sensing catheters in the HD mapping group may have contributed to the observed differences in outcomes. A larger sample size would have likely allowed the study to achieve statistical significance when comparing recurrent AAFL rates between groups. Despite these limitations however, this study provides strong support for the clinical utility of HD mapping in AAFL ablation. Future multi-center, randomized trials should validate these findings and examine factors not studied here, such as procedure fluoroscopy time and complication rates between groups. Long-term benefits should also be further investigated, as some prior studies for example have shown no significant decrease in anti-arrhythmic drug use at 1-year follow-up5 and significantly decreased rates of sinus rhythm maintenance for repeat ablations compared with single ablations6. Research on HD mapping in patients with specific comorbidities could also provide insights into its broader applicability. For instance, one study showed a greater chance of acute procedural failure in patients with a history of surgical correction for congenital heart disease.7 Though HD-mapping-guided ablation demonstrates higher acute procedural success, several studies have shown long-term recurrence rates remain significant.8, 9 Hence, further research is needed to identify strategies to reduce these rates. In this context, the development of new mapping tools, such as the Octaray TM system (Biosense Webster Inc., Irvine, CA, USA)10 and the Ensite TM Omnipolar Technology (OT) (Abbott, Chicago, IL, USA)11, may offer improved outcomes. Further research is also needed to assess the clinical outcomes, healthcare utilization and biomarker response for ablation of AAFL with HD mapping in the setting of heart failure with reduced ejection fraction.12 To the best of our knowledge, this is the first such study to demonstrate that ablation with HD mapping for AAFL results in reduced re-hospitalization and ED visits. Future research should attempt to expand on these findings to evaluate potential cost-benefit and impact on patient quality of life.References:1. Cherian Tharian S, Supple G, Smietana J, Santangeli P, Nazarian S, Lin D, Hyman Matthew C, Walsh K, Marchlinski F and Arkles J. Idiopathic Atypical Atrial Flutter Is Associated With a Distinct Atriopathy.JACC: Clinical Electrophysiology . 2021;7:1193-1195.2. Ko Ko NL, Sriramoju A, Khetarpal BK and Srivathsan K. Atypical atrial flutter: review of mechanisms, advances in mapping and ablation outcomes.Curr Opin Cardiol . 2022;37:36-45.3. Raymond-Paquin A, Pillai A, Myadam R, Mankad P, Lovejoy S, Koneru JN and Ellenbogen KA. Atypical atrial flutter catheter ablation in the era of high-density mapping.J Interv Card Electrophysiol . 2023;66:1807-1815.4. Sink JC, Kasen; Uppalapati, Lakshmi; Lancki, Nicola; Peigh, Graham; Lohrmann, Graham; Elsayed, Mahmoud; Carneiro, Herman; Baman, Jayson; Pfenniger, Anna; Patil, Kaustubha D.; Verma, Nishant; Arora, Rishi; Kim, Susan S.; Chicos, Alexandru B.; Lin, Albert C.; Knight, Bradley P.; Passman, Rod S. Association Between High-Density Mapping of Atypical Atrial Flutter, Clinical Outcomes and Healthcare Utilization. Journal of Cardiovascular Electrophysiology . 2024.5. Balt JC, Klaver MN, Mahmoodi BK, van Dijk VF, Wijffels MCEF and Boersma LVA. High-density versus low-density mapping in ablation of atypical atrial flutter.Journal of Interventional Cardiac Electrophysiology . 2021;62:587-599.6. Marazzato J, Cappabianca G, Angeli F, Crippa M, Golino M, Ferrarese S, Beghi C and De Ponti R. Catheter ablation of atrial tachycardias after mitral valve surgery: a systematic review and meta‐analysis. Journal of Cardiovascular Electrophysiology . 2020;31:2632-2641.7. Delacretaz E, Ganz Leonard I, Soejima K, Friedman Peter L, Walsh Edward P, Triedman John K, Sloss Laurence J, Landzberg Michael J and Stevenson William G. Multiple atrial macro–re-entry circuits in adults with repaired congenital heart disease: entrainment mapping combined with three-dimensional electroanatomic mapping.Journal of the American College of Cardiology . 2001;37:1665-1676.8. Lozano-Granero C, Moreno J, Sanchez-Perez I, Matia-Frances R, Hernandez-Madrid A, Zamorano JL and Franco E. Results of atypical flutter ablation in the era of high density electroanatomical mapping (the RAFAELA study). European Heart Journal . 2023;44.9. Anter E, McElderry TH, Contreras-Valdes FM, Li J, Tung P, Leshem E, Haffajee CI, Nakagawa H and Josephson ME. Evaluation of a novel high-resolution mapping technology for ablation of recurrent scar-related atrial tachycardias. Heart Rhythm . 2016;13:2048-2055.10. Sroubek J, Rottmann M, Barkagan M, Leshem E, Shapira‐Daniels A, Brem E, Fuentes‐Ortega C, Malinaric J, Basu S and Bar‐Tal M. A novel octaray multielectrode catheter for high‐resolution atrial mapping: electrogram characterization and utility for mapping ablation gaps. Journal of Cardiovascular Electrophysiology . 2019;30:749-757.11. Rillo M, Palamà Z, Punzi R, Vitanza S, Aloisio A, Polini S, Tucci A, Pollastrelli A, Zonno F, Anastasia A, Giannattasio CF and My L. A new interpretation of nonpulmonary vein substrates of the left atrium in patients with atrial fibrillation. Journal of Arrhythmia . 2021;37:338-347.12. Pascual-Figal D, Wachter R, Senni M, Bao W, Noè A, Schwende H, Butylin D, Prescott MF; TRANSITION Investigators. NT-proBNP Response to Sacubitril/Valsartan in Hospitalized Heart Failure Patients With Reduced Ejection Fraction: TRANSITION Study. JACC Heart Fail Oct 2020;8(10):822-833.

not-yet-known not-yet-known not-yet-known unknown The Efficiency of using KardiaMobile 6L in the Cardiac Electrophysiology Clinic Bahjat Z. Ghazzal MD1, Marwan M. Refaat, MD2 1 Division of Cardiology, Department of Internal Medicine, University of Massachusetts Chan Medical School , Worcester, Massachusetts, USA 2 Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon Running Title: The Efficiency of KardiaMobile 6L in Clinic Words: 719 (excluding the title page and references) Keywords: Electrocardiogram, cardiac arrhythmias, cardiology, cardiovascular diseases, Utilization Time, Efficiency Funding: None Disclosures: None Corresponding Author: Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCP Tenured Professor of Medicine Tenured Professor of Biochemistry and Molecular Genetics Member, Division of Cardiology/ Section of Cardiac Electrophysiology Director, Cardiovascular Fellowship ProgramAmerican University of Beirut Faculty of Medicine and Medical Center PO Box 11-0236, Riad El-Solh 1107 2020- Beirut, Lebanon US Address: 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USA Office: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct) Electrocardiography (ECG) is an essential diagnostic tool in cardiology, allowing for the detection and management of various cardiac conditions. Traditional 12-lead ECGs, while comprehensive, can be time-consuming and may impact clinic efficiency. This may be particularly important in outpatient cardiology clinics, where time can often be a scarce resource. A survey distributed at the 2022 ESC congress found that while most cardiologists believe that consultations should last 30 to 45 minutes, they often have only 20 minutes or less.1 Although the effects of time pressure have not been extensively studied in cardiology and cardiac electrophysiology outpatient clinics, research in primary care has linked it to increased physician stress, burnout, intent to leave the practice2 in addition to lower diagnosis rates and higher follow-up care rates3. Research has also shown that increasing system efficiency and improving patient cycle time in primary care clinics can improve patient experience and access as well as staff satisfaction.4 Thus, the introduction of KardiaMobile 6-lead ECG (Figure 1), a more portable and user-friendly device, could present an opportunity to streamline ECG collection and potentially improve clinic time utilization. The study by Gaddam et al. explores this potential by comparing room utilization times between KardiaMobile 6-lead ECG and the standard 12-lead ECG in a cardiology clinic setting. In their study, Gaddam et al. conducted a single-center, non-randomized trial involving 100 patients aged 18 to 89, excluding those with resting tremor. The participants were divided into two groups: one underwent ECG collection using KardiaMobile 6-lead ECG, and the other using the traditional 12-lead ECG. The primary outcome measured was room utilization time, with secondary outcomes including the need for additional 12-lead ECGs. The results demonstrated a significant reduction in room utilization time with KardiaMobile 6-lead ECG (7.27 minutes) compared to the 12-lead ECG (10.33 minutes, p < 0.001). Only 16% of visits in the KardiaMobile 6-lead ECG group required an additional 12-lead ECG, indicating that KardiaMobile 6-lead ECG is sufficient for most clinical needs. The primary benefit of 6-lead ECGs lies in their portability and ease of use, making them suitable for continuous monitoring and rapid assessment in both clinical and non-clinical settings. Although research on this subject is still limited, a recent prospective study of 1,015 participants found that the KardiaMobile 6-lead ECG demonstrates a high level of agreement with 12-lead ECGs for certain parameters like PR interval, QRS duration, and cardiac axis, but may be less effective for detecting conditions that require detailed precordial lead information, such as left ventricular hypertrophy or specific ischemic changes.5 Other studies have also corroborated acceptable agreement in certain ECG parameters between 6-lead and 12-lead ECG’s, however, highlighting the 12-lead ECG’s advantage in certain situations where broader and more detailed data collection is required.6,7 While this study was well-conducted, minor limitations exist. The study follows a non-randomized design, which may potentially introduce selection bias and the team members were non-blinded, which may introduce observer bias. Additionally, the relatively small sample size and single-center nature of the study may limit generalizability. It must also be noted that nearly half of the patients in each group (KardiaMobile 6-lead ECG vs. 12-lead ECG) visited the clinic for atrial fibrillation and/or atrial flutter follow-up, conditions that can be detected with just a 1-lead ECG. Finally, while the study shows a statistically significant reduction in average room utilization time by 3.07 minutes, it does not assess whether this reduction translated to meaningful improvements in tangible clinic efficiency outcomes. Despite these limitations, the study provides valuable insights into the potential benefits of integrating KardiaMobile 6-lead ECG into clinical practice. It could lead to improved clinical workflows, allowing clinicians to see more patients without compromising the quality of care. This device may also be particularly beneficial in remote or resource-limited settings where traditional 12-lead ECGs are impractical. Future research should focus on larger, randomized trials to validate these findings and explore the long-term benefits and potential limitations of KardiaMobile 6-lead ECG in diverse clinical environments. Furthermore, investigating the use of KardiaMobile 6-lead ECG in specific patient populations, such as those with complex arrhythmias or comorbidities associated with arrhythmias such as cardiomyopathies and heart failure, could provide additional insights into its clinical utility.8,9 The development of guidelines and protocols for integrating KardiaMobile 6-lead ECG into routine practice will be essential to maximize its benefits and ensure patient safety. Legend Figure 1: Kardia 6L Electrocardiogram (Mountain View, CA) References: https://doi.org/10.1016/j.jelectrocard.2021.03.008 1. Sala O, Moscatelli S. Time matters. Global assessment of quality, duration and mismatch between real practice working conditions and physician needs performing outpatients cardiological consultations. European Heart Journal . 2022;43. doi: 10.1093/eurheartj/ehac544.28352. Prasad K, Poplau S, Brown R, Yale S, Grossman E, Varkey AB, Williams E, Neprash H, Linzer M, for the Healthy Work Place I. Time Pressure During Primary Care Office Visits: a Prospective Evaluation of Data from the Healthy Work Place Study. Journal of General Internal Medicine . 2020;35:465-472. doi: 10.1007/s11606-019-05343-63. Freedman S, Golberstein E, Huang TY, Satin DJ, Smith LB. Docs with their eyes on the clock? The effect of time pressures on primary care productivity. J Health Econ . 2021;77:102442. doi: 10.1016/j.jhealeco.2021.1024424. Robinson J, Porter M, Montalvo Y, Peden CJ. Losing the wait: improving patient cycle time in primary care. BMJ Open Quality . 2020;9:e000910. doi: 10.1136/bmjoq-2019-0009105. Azram M, Ahmed N, Leese L, Brigham M, Bowes R, Wheatcroft SB, Ngantcha M, Stegemann B, Crowther G, Tayebjee MH. Clinical validation and evaluation of a novel six-lead handheld electrocardiogram recorder compared to the 12-lead electrocardiogram in unselected cardiology patients (EVALECG Cardio). European Heart Journal - Digital Health . 2021;2:643-648. doi: 10.1093/ehjdh/ztab0836. Madias JE. A Comparison of 2-Lead, 6-Lead, and 12-Lead ECGs in Patients With Changing Edematous States: Implications for the Employment of Quantitative Electrocardiography in Research and Clinical Applications. CHEST . 2003;124:2057-2063. doi: 10.1378/chest.124.6.20577. Orchard JJ, Orchard JW, Raju H, La Gerche A, Puranik R, Semsarian C. Comparison between a 6‑lead smartphone ECG and 12‑lead ECG in athletes. Journal of Electrocardiology . 2021;66:95-97. doi: 8. El Moheb M, Nicolas J, Khamis AM, Iskandarani G, Akl EA, Refaat M. Implantable Cardiac Defibrillators for patients with non-ischaemic cardiomyopathy. Cochrane Database Syst Rev Dec 2018; 12: CD012738 9. Pascual-Figal D, Wachter R, Senni M, Bao W, Noè A, Schwende H, Butylin D, Prescott MF; TRANSITION Investigators. NT-proBNP Response to Sacubitril/Valsartan in Hospitalized Heart Failure Patients With Reduced Ejection Fraction: TRANSITION Study. JACC Heart Fail. Aug 2020; S2213-1779(20)30336-X.