A complex Case of Wolff-Parkinson-White Syndrome, Atrial Fibrillation and Myocarditis: A Unique Clinical Intersection and the Utility of Open Window Mapping in Ablation

A complex Case of Wolff-Parkinson-White Syndrome, Atrial Fibrillation and Myocarditis: A Unique Clinical Intersection and the Utility of Open Window Mapping in Ablation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report A complex Case of Wolff-Parkinson-White Syndrome, Atrial Fibrillation and Myocarditis: A Unique Clinical Intersection and the Utility of Open Window Mapping in Ablation Georgios Tsitsinakis, Nikolaos Tsiamis, Evaggelos Ballas, Christo Kole, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9418000/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The coexistence of Wolff-Parkinson-White (WPW) syndrome and Atrial Fibrillation (AF) presents a significant risk for hemodynamic collapse and sudden cardiac death. Case presentation We describe the case of a 21-year-old patient presenting with pre-excited AF and significantly elevated troponin levels. Cardiac Magnetic Resonance (CMR) imaging suggested focal myocarditis. High-density mapping using an "Open Window" configuration was utilized to successfully localize and ablate a left lateral accessory pathway. Conclusions This case highlights the diagnostic challenge of differentiating primary myocarditis from tachycardia-mediated myocardial injury and demonstrates the utility of high-density mapping using an "Open Window" configuration to facilitate successful ablation. Atrial Fibrillation Wolff-Parkinson-White Syndrome Myocarditis Catheter Ablation High-Density Mapping Case Report Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Atrial fibrillation (AF) is a common arrhythmia in adults and Wolff-Parkinson-White (WPW) syndrome is a well-known cause of paroxysmal supraventricular tachycardia (PSVT). The coexistence of AF and WPW is rare, particularly in young adults ( 1 ). Wolff-Parkinson-White syndrome is a condition characterized by accessory atrioventricular pathways (APs). These APs can permit atrioventricular reentrant tachycardia (AVRT) or rapid and potentially life-threatening conduction of atrial fibrillation to the ventricle, which leads to referral for catheter ablation ( 2 ),( 3 ). Furthermore, the presence of myocarditis in a patient with both AF and WPW is an unusual clinical presentation. We describe a unique case of a 21-year-old patient with AF, WPW, and myocarditis, and discuss the role of the open window mapping technique in the ablation of the accessory pathway. Learning Objectives Differentiate between primary acute myocarditis and tachycardia-mediated myocardial injury (Type 2 MI) in young patients presenting with pre-excited atrial fibrillation and elevated troponin Identify the "FBI" (Fast, Broad, Irregular) ECG pattern characteristic of pre-excited atrial fibrillation and recognize the immediate risk of hemodynamic collapse. Apply the high-density "Open Window" mapping technique to successfully discriminate accessory pathway potentials from fused ventricular signals. History of Presentation A 21-year-old, previously healthy male presented to the emergency department reporting acute onset palpitations initiating one hour prior to arrival. The patient denied any prodromal viral symptoms such as fever, gastrointestinal distress, or flu-like illness in the weeks preceding presentation. The initial 12-lead ECG revealed atrial fibrillation (AF) with a rapid ventricular response and a wide QRS complex morphology consistent with pre-excited AF (Image 1). The patient remained hemodynamically stable but symptomatic. Notably, the arrhythmia spontaneously converted to sinus rhythm prior to electrical cardioversion. The post-conversion ECG demonstrated a short PR interval and a delta wave suggestive of a left-lateral accessory pathway (Image 2). Laboratory evaluation revealed a markedly elevated high-sensitivity Troponin I level of 4000 pg/mL (Laboratory reference range: <34 pg/mL). The patient was admitted to the cardiac intensive care unit for continuous monitoring. Image 1. 12-lead ECG at presentation showing pre-excited Atrial Fibrillation. Note the irregular R-R intervals and varying degrees of QRS width (FBI: Fast, Broad, Irregular), characteristic of conduction over an accessory pathway. Image 2. 12-lead ECG during Sinus Rhythm. A delta wave is visible in leads I and aVL, with R/S transition >V1, consistent with a left-lateral accessory pathway. Investigation Given the significant troponin elevation in a young patient, a coronary angiogram was performed to exclude coronary anomalies or embolism; this was unremarkable. Cardiac Magnetic Resonance (CMR) imaging was subsequently performed to evaluate the myocardial substrate. CMR revealed focal subepicardial Late Gadolinium Enhancement (LGE) in the basolateral wall of the left ventricle, involving < 1% of the LV mass (Image 3). While the troponin elevation could be attributed to severe demand ischemia from rapid pre-excited AF (Type 2 myocardial infarction), the subepicardial localization of LGE raised the suspicion of an acute inflammatory process (myocarditis). Image 3. Cardiac MRI, revealing lesions consistent with myocarditis. Management Following stabilization, the patient was taken to the electrophysiology laboratory. The procedure was performed under conscious sedation. Diagnostic catheters were positioned in the coronary sinus (CS), high right atrium (HRA), and right ventricular apex (RVA). Baseline Measurements : The patient was in sinus rhythm. Baseline intervals revealed pre-excitation consistent with a left-lateral pathway. Induction : Programmed stimulation induced orthodromic Atrioventricular Reentrant Tachycardia (AVRT), confirming the AP participation. Atrial fibrillation was also easily inducible. Mapping Strategy : A transseptal puncture was performed. Mapping was conducted using a 16-electrode high-density grid catheter (Advisor™ HD Grid, Abbott Laboratories). To ensure accurate annotation of the accessory pathway potential—which often fuses with the local ventricular signal—we utilized an "Open Window Mapping" (OWM) configuration on the EnSite Precision™ system. The Window of Interest (WOI) was widened to encompass both atrial and ventricular electrograms. Ablation : The HD Grid identified the site of earliest ventricular activation during sinus rhythm and the sharpest AP potential at the left lateral mitral annulus (Image 7). Radiofrequency energy was delivered using an open-irrigated contact force catheter (TactiCath™, Abbott). A high-power strategy (45–50 W) was utilized to ensure adequate lesion formation in the high-flow environment of the mitral annulus, titrated against impedance drop and local electrogram attenuation. Outcome : Ablation resulted in immediate loss of pre-excitation (Image 5). Post-ablation testing with adenosine and aggressive pacing confirmed bidirectional block of the accessory pathway. Image 4. Intracardiac electrograms showing the onset of pre-excited AF. Image 5. Intracardiac electrograms during RF ablation. Note the abrupt loss of the delta wave and normalization of the AH-HV intervals during energy delivery (arrow), signifying successful pathway ablation. Image 6. Sinus rhythm after ablation. Image 7. OWT mapping. The location of initial ventricular activation via the accessory pathway was identified. The ablation sites are marked as red dots. Discussion This case illustrates the management of a "perfect storm" of pre-excited AF and myocardial injury. The primary clinical challenge was differentiating between acute myocarditis and tachycardia-induced myocardial injury. In WPW patients presenting with rapid AF (ventricular rates often > 250 bpm), troponin elevation is common due to supply-demand mismatch. However, the specific CMR finding of subepicardial LGE favored a primary inflammatory or focal cardiomyopathic process, rather than pure ischemia which is typically subendocardial. Despite the suspicion of active myocarditis, which typically mandates delaying non-urgent procedures, catheter ablation was deemed necessary due to the life-threatening nature of the patient’s presenting arrhythmia (pre-excited AF). The use of the "Open Window" mapping technique with the HD Grid allowed for precise discrimination of the AP potential from the surrounding far-field signals. This is particularly useful in lateral pathways where signal fusion is common. By successfully ablating the pathway, we eliminated the risk of SCD, allowing for safe supportive management of the underlying myocardial inflammation. Conclusion This unique case highlights the importance of thorough evaluation and management of young patients presenting with palpitations and elevated cardiac biomarkers. The presence of multiple overlapping cardiac conditions, such as AF, WPW, and myocarditis, requires a tailored approach to ensure optimal patient outcomes. The successful use of the open window mapping technique in this case demonstrates its utility in the ablation of accessory pathways, particularly in complex clinical scenarios. It seems that this technique is capable of accurate identification of the site of successful accessory pathway ablation using high-density mapping, and therefore may complement traditional mapping techniques, particularly for challenging cases. Abbreviations AF: Atrial Fibrillation AP: Accessory Pathway AVRT: Atrioventricular Reentrant Tachycardia CMR: Cardiac Magnetic Resonance CS: Coronary Sinus ECG: Electrocardiogram FBI: Fast, Broad, Irregular HRA: High Right Atrium ICU: Intensive Care Unit LGE: Late Gadolinium Enhancement MRI: Magnetic Resonance Imaging OWM: Open Window Mapping PSVT: Paroxysmal Supraventricular Tachycardia RF: Radiofrequency RVA: Right Ventricular Apex SCD: Sudden Cardiac Death WPW: Wolff-Parkinson-White Declarations Consent for publication Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Funding: Not applicable. Conflicts of interest/Competing interests: The authors declare that they have no conflict of interest. Ethics approval: No ethical committee approval was required for this case report by the Department, as this article does not contain studies with human participants or animals. Consent to participate: Informed consent was obtained from the patient included in this study. Written Consent for publication: The patient gave written consent to use personal data for the publication of this case report and any accompanying images. Availability of data and material: All data underlying the findings are fully available. Code availability: Not applicable. Authors' contributions: All authors contributed significantly to the work and agree with the manuscript content. GT, NT, ΕΒ and ΙΜ were responsible for writing and design; CK, CT, and AK performed analysis and interpretation; AK provided writing and overall monitoring. All authors approved the final version. The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. References Page RL, Joglar JA, Caldwell MA, Calkins H, Conti JB, Deal BJ, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2016;133(14):e471–505. 10.1016/j.jacc.2015.08.856 . Blomström-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias—executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines. J Am Coll Cardiol. 2003;42(8):1493–531. 10.1016/j.jacc.2003.08.013 . Scheinman M, Calkins H, Gillette P, Klein R, Lerman BB, Morady F, et al. NASPE policy statement on catheter ablation: personnel, policy, procedures, and therapeutic recommendations. Pacing Clin Electrophysiol. 2003;26(3):789–99. 10.1046/j.1460-9592.2003.00139.x . Friedrich MG, Sechtem U, Schulz-Menger J, Holmvang G, Alakija P, Cooper LT, et al. Cardiovascular magnetic resonance in myocarditis: A JACC White Paper. J Am Coll Cardiol. 2009;53(17):1475–87. 10.1016/j.jacc.2009.02.007 . Caforio AL, Pankuweit S, Arbustini E, Basso C, Gimeno-Blanes J, Felix SB, et al. Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases. Eur Heart J. 2013;34(33):2636–48. 48a-48d. Calkins H, Kuck KH, Cappato R, Brugada J, Camm AJ, Chen SA, 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. Europace. 2012;14(4):528–606. 10.1093/europace/eus027 . Chen SA, Tai CT. Ablation of atrioventricular accessory pathways: current technique-state of the art. Pacing Clin Electrophysiol. 2001;24(12):1795–809. 10.1046/j.1460-9592.2001.01795.x . Cooper LT. Jr. Myocarditis. N Engl J Med. 2009;360(15):1526–38. 10.1056/NEJMra0800028 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9418000","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":630414515,"identity":"95c6bbe5-e371-4e8e-9d5f-89eafaf26b51","order_by":0,"name":"Georgios Tsitsinakis","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Georgios","middleName":"","lastName":"Tsitsinakis","suffix":""},{"id":630414516,"identity":"65191b6f-0c18-42c8-a3d4-038e10279af0","order_by":1,"name":"Nikolaos Tsiamis","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYDACZjYQKQFkMDA+ALJ4+IjScgCihdkApIWNsDVgLRCWBJSPH5izsyUwf/hjIa/bzv6s8muOnQwbA/PDRzfwaLFsZjvAcLBNwnDbYR6z27LbkoEOYzM2zsGjxeAwewPDwQYJRqAWttuS25iBWnjYpAlqOfBHwn7bYfZnxZLb6onRAnTYATaJxG2HGcwYP4LsIkJLwoGzbRLJQMXG0ozbjvOwMRPyy/ljhg8q/tTZbjt//OHHn9uq7fnZmx8+xqcFBA7AGMw8YJKAchTA+IMU1aNgFIyCUTBiAAC/EkN2+h7+OwAAAABJRU5ErkJggg==","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":true,"prefix":"","firstName":"Nikolaos","middleName":"","lastName":"Tsiamis","suffix":""},{"id":630414517,"identity":"e19ac7e0-8c38-43e0-8c13-2f146e63fc17","order_by":2,"name":"Evaggelos Ballas","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Evaggelos","middleName":"","lastName":"Ballas","suffix":""},{"id":630414518,"identity":"83723c1c-e163-4d26-8305-b25a06d7bfc4","order_by":3,"name":"Christo Kole","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Christo","middleName":"","lastName":"Kole","suffix":""},{"id":630414519,"identity":"73d88939-f882-41cd-9c89-ab00b1b8569b","order_by":4,"name":"Ioannis Mavrogenis","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ioannis","middleName":"","lastName":"Mavrogenis","suffix":""},{"id":630414520,"identity":"8b72a2da-9681-49ff-b147-3a165ad85309","order_by":5,"name":"Christos Tountas","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Christos","middleName":"","lastName":"Tountas","suffix":""},{"id":630414521,"identity":"99b62113-d7f2-498d-83fb-7cc31d756bfa","order_by":6,"name":"Apostolos Kakkavas","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Apostolos","middleName":"","lastName":"Kakkavas","suffix":""},{"id":630414522,"identity":"60748cc9-d2ea-4b28-9f21-a962d7647b7a","order_by":7,"name":"Anastasia Kitsiou","email":"","orcid":"","institution":"Sismanoglio General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Anastasia","middleName":"","lastName":"Kitsiou","suffix":""}],"badges":[],"createdAt":"2026-04-14 16:38:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9418000/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9418000/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108182699,"identity":"df1cf3a0-dbcd-4ac5-955d-75eb69575c27","added_by":"auto","created_at":"2026-04-30 08:59:30","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":453519,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 1.\u003c/strong\u003e 12-lead ECG at presentation showing pre-excited Atrial Fibrillation. Note the irregular R-R intervals and varying degrees of QRS width (FBI: Fast, Broad, Irregular), characteristic of conduction over an accessory pathway.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/722d20b3b4cd2ae3186b8f44.jpeg"},{"id":108105486,"identity":"debb8b25-6742-48d0-94dd-ce89925b6f4d","added_by":"auto","created_at":"2026-04-29 11:49:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":9390314,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 2.\u003c/strong\u003e 12-lead ECG during Sinus Rhythm. A delta wave is visible in leads I and aVL, with R/S transition \u0026gt;V1, consistent with a left-lateral accessory pathway.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/0a2d4073137fe02ed449e7b8.png"},{"id":108182253,"identity":"25f621da-af3b-4fb4-bde6-0e09e7b22c61","added_by":"auto","created_at":"2026-04-30 08:59:17","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1748063,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 3.\u003c/strong\u003e Cardiac MRI, revealing lesions consistent with myocarditis.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/e767dccc980f7c040033026b.png"},{"id":108182637,"identity":"476badce-4d6e-4082-8175-0c992913e861","added_by":"auto","created_at":"2026-04-30 08:59:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":666786,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 4.\u003c/strong\u003e Intracardiac electrograms showing the onset of pre-excited AF.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/290973400092974a3144fed4.png"},{"id":108105489,"identity":"1102cba3-8bc0-43ca-801b-d0cdc8393546","added_by":"auto","created_at":"2026-04-29 11:49:15","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":363610,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 5.\u003c/strong\u003e Intracardiac electrograms during RF ablation. Note the abrupt loss of the delta wave and normalization of the AH-HV intervals during energy delivery (arrow), signifying successful pathway ablation.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/0636a16425d9bee591414698.png"},{"id":108804045,"identity":"1bd44cba-c2f2-4368-8c70-dd5577d5bf36","added_by":"auto","created_at":"2026-05-08 15:14:56","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":349369,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 6.\u003c/strong\u003e Sinus rhythm after ablation.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/fae241b3e3d3b7d25e2564a1.png"},{"id":108105492,"identity":"b9a263b3-c778-4a6c-8ee1-08f4dbe7bf5c","added_by":"auto","created_at":"2026-04-29 11:49:15","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":335802,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage 7.\u003c/strong\u003e OWT mapping. The location of initial ventricular activation via the accessory pathway was identified. The ablation sites are marked as red dots.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/e85b9905c520cccbbd315e0b.png"},{"id":108809125,"identity":"28e8d2a5-18ba-4437-b767-52739d94d81f","added_by":"auto","created_at":"2026-05-08 15:50:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":13372386,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9418000/v1/be649803-dfeb-4862-a16f-ab10d4bfc4b3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eA complex Case of Wolff-Parkinson-White Syndrome, Atrial Fibrillation and Myocarditis: A Unique Clinical Intersection and the Utility of Open Window Mapping in Ablation\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAtrial fibrillation (AF) is a common arrhythmia in adults and Wolff-Parkinson-White (WPW) syndrome is a well-known cause of paroxysmal supraventricular tachycardia (PSVT). The coexistence of AF and WPW is rare, particularly in young adults (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Wolff-Parkinson-White syndrome is a condition characterized by accessory atrioventricular pathways (APs). These APs can permit atrioventricular reentrant tachycardia (AVRT) or rapid and potentially life-threatening conduction of atrial fibrillation to the ventricle, which leads to referral for catheter ablation (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e),(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Furthermore, the presence of myocarditis in a patient with both AF and WPW is an unusual clinical presentation. We describe a unique case of a 21-year-old patient with AF, WPW, and myocarditis, and discuss the role of the open window mapping technique in the ablation of the accessory pathway.\u003c/p\u003e"},{"header":"Learning Objectives","content":"\u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eDifferentiate between primary acute myocarditis and tachycardia-mediated myocardial injury (Type 2 MI) in young patients presenting with pre-excited atrial fibrillation and elevated troponin\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIdentify the \"FBI\" (Fast, Broad, Irregular) ECG pattern characteristic of pre-excited atrial fibrillation and recognize the immediate risk of hemodynamic collapse.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eApply the high-density \"Open Window\" mapping technique to successfully discriminate accessory pathway potentials from fused ventricular signals.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"History of Presentation","content":"\u003cp\u003eA 21-year-old, previously healthy male presented to the emergency department reporting acute onset palpitations initiating one hour prior to arrival. The patient denied any prodromal viral symptoms such as fever, gastrointestinal distress, or flu-like illness in the weeks preceding presentation. The initial 12-lead ECG revealed atrial fibrillation (AF) with a rapid ventricular response and a wide QRS complex morphology consistent with pre-excited AF (Image 1). The patient remained hemodynamically stable but symptomatic. Notably, the arrhythmia spontaneously converted to sinus rhythm prior to electrical cardioversion. The post-conversion ECG demonstrated a short PR interval and a delta wave suggestive of a left-lateral accessory pathway (Image 2). Laboratory evaluation revealed a markedly elevated high-sensitivity Troponin I level of 4000 pg/mL (Laboratory reference range: \u0026lt;34 pg/mL). The patient was admitted to the cardiac intensive care unit for continuous monitoring.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 1.\u003c/b\u003e 12-lead ECG at presentation showing pre-excited Atrial Fibrillation. Note the irregular R-R intervals and varying degrees of QRS width (FBI: Fast, Broad, Irregular), characteristic of conduction over an accessory pathway.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 2.\u003c/b\u003e 12-lead ECG during Sinus Rhythm. A delta wave is visible in leads I and aVL, with R/S transition \u0026gt;V1, consistent with a left-lateral accessory pathway.\u003c/p\u003e "},{"header":"Investigation","content":"\u003cp\u003eGiven the significant troponin elevation in a young patient, a coronary angiogram was performed to exclude coronary anomalies or embolism; this was unremarkable. Cardiac Magnetic Resonance (CMR) imaging was subsequently performed to evaluate the myocardial substrate. CMR revealed focal subepicardial Late Gadolinium Enhancement (LGE) in the basolateral wall of the left ventricle, involving\u0026thinsp;\u0026lt;\u0026thinsp;1% of the LV mass (Image 3). While the troponin elevation could be attributed to severe demand ischemia from rapid pre-excited AF (Type 2 myocardial infarction), the subepicardial localization of LGE raised the suspicion of an acute inflammatory process (myocarditis).\u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 3.\u003c/b\u003e Cardiac MRI, revealing lesions consistent with myocarditis.\u003c/p\u003e"},{"header":"Management","content":"\u003cp\u003eFollowing stabilization, the patient was taken to the electrophysiology laboratory. The procedure was performed under conscious sedation. Diagnostic catheters were positioned in the coronary sinus (CS), high right atrium (HRA), and right ventricular apex (RVA).\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eBaseline Measurements\u003c/b\u003e: The patient was in sinus rhythm. Baseline intervals revealed pre-excitation consistent with a left-lateral pathway.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eInduction\u003c/b\u003e: Programmed stimulation induced orthodromic Atrioventricular Reentrant Tachycardia (AVRT), confirming the AP participation. Atrial fibrillation was also easily inducible.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eMapping Strategy\u003c/b\u003e: A transseptal puncture was performed. Mapping was conducted using a 16-electrode high-density grid catheter (Advisor\u0026trade; HD Grid, Abbott Laboratories). To ensure accurate annotation of the accessory pathway potential\u0026mdash;which often fuses with the local ventricular signal\u0026mdash;we utilized an \"Open Window Mapping\" (OWM) configuration on the EnSite Precision\u0026trade; system. The Window of Interest (WOI) was widened to encompass both atrial and ventricular electrograms.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eAblation\u003c/b\u003e: The HD Grid identified the site of earliest ventricular activation during sinus rhythm and the sharpest AP potential at the left lateral mitral annulus (Image 7). Radiofrequency energy was delivered using an open-irrigated contact force catheter (TactiCath\u0026trade;, Abbott). A high-power strategy (45\u0026ndash;50 W) was utilized to ensure adequate lesion formation in the high-flow environment of the mitral annulus, titrated against impedance drop and local electrogram attenuation.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eOutcome\u003c/b\u003e: Ablation resulted in immediate loss of pre-excitation (Image 5). Post-ablation testing with adenosine and aggressive pacing confirmed bidirectional block of the accessory pathway.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 4.\u003c/b\u003e Intracardiac electrograms showing the onset of pre-excited AF.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 5.\u003c/b\u003e Intracardiac electrograms during RF ablation. Note the abrupt loss of the delta wave and normalization of the AH-HV intervals during energy delivery (arrow), signifying successful pathway ablation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 6.\u003c/b\u003e Sinus rhythm after ablation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImage 7.\u003c/b\u003e OWT mapping. The location of initial ventricular activation via the accessory pathway was identified. The ablation sites are marked as red dots.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case illustrates the management of a \"perfect storm\" of pre-excited AF and myocardial injury. The primary clinical challenge was differentiating between acute myocarditis and tachycardia-induced myocardial injury. In WPW patients presenting with rapid AF (ventricular rates often\u0026thinsp;\u0026gt;\u0026thinsp;250 bpm), troponin elevation is common due to supply-demand mismatch. However, the specific CMR finding of \u003cem\u003esubepicardial\u003c/em\u003e LGE favored a primary inflammatory or focal cardiomyopathic process, rather than pure ischemia which is typically subendocardial.\u003c/p\u003e \u003cp\u003eDespite the suspicion of active myocarditis, which typically mandates delaying non-urgent procedures, catheter ablation was deemed necessary due to the life-threatening nature of the patient\u0026rsquo;s presenting arrhythmia (pre-excited AF). The use of the \"Open Window\" mapping technique with the HD Grid allowed for precise discrimination of the AP potential from the surrounding far-field signals. This is particularly useful in lateral pathways where signal fusion is common. By successfully ablating the pathway, we eliminated the risk of SCD, allowing for safe supportive management of the underlying myocardial inflammation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis unique case highlights the importance of thorough evaluation and management of young patients presenting with palpitations and elevated cardiac biomarkers. The presence of multiple overlapping cardiac conditions, such as AF, WPW, and myocarditis, requires a tailored approach to ensure optimal patient outcomes. The successful use of the open window mapping technique in this case demonstrates its utility in the ablation of accessory pathways, particularly in complex clinical scenarios. It seems that this technique is capable of accurate identification of the site of successful accessory pathway ablation using high-density mapping, and therefore may complement traditional mapping techniques, particularly for challenging cases.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003eAF:\u003c/strong\u003e Atrial Fibrillation\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAP:\u003c/strong\u003e Accessory Pathway\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAVRT:\u003c/strong\u003e Atrioventricular Reentrant Tachycardia\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCMR:\u003c/strong\u003e Cardiac Magnetic Resonance\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCS:\u003c/strong\u003e Coronary Sinus\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eECG:\u003c/strong\u003e Electrocardiogram\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFBI:\u003c/strong\u003e Fast, Broad, Irregular\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHRA:\u003c/strong\u003e High Right Atrium\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eICU:\u003c/strong\u003e Intensive Care Unit\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLGE:\u003c/strong\u003e Late Gadolinium Enhancement\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMRI:\u003c/strong\u003e Magnetic Resonance Imaging\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOWM:\u003c/strong\u003e Open Window Mapping\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePSVT:\u003c/strong\u003e Paroxysmal Supraventricular Tachycardia\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRF:\u003c/strong\u003e Radiofrequency\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRVA:\u003c/strong\u003e Right Ventricular Apex\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSCD:\u003c/strong\u003e Sudden Cardiac Death\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWPW:\u003c/strong\u003e Wolff-Parkinson-White\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConsent for publication\u003c/h2\u003e \u003cp\u003e Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.\u003c/p\u003e \u003c/p\u003e\n\u003cp\u003eFunding: Not applicable.\u003c/p\u003e\n\u003cp\u003eConflicts of interest/Competing interests:\u0026nbsp;The authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003eEthics approval:\u0026nbsp;No ethical committee approval was required for this case report by the Department, as this article does not contain studies with human participants or animals.\u003c/p\u003e\n\u003cp\u003eConsent to participate:\u0026nbsp;Informed consent was obtained from the patient included in this study.\u003c/p\u003e\n\u003cp\u003eWritten Consent for publication:\u0026nbsp;The patient gave written consent to use personal data for the publication of this case report and any accompanying images.\u003c/p\u003e\n\u003cp\u003eAvailability of data and material:\u0026nbsp;All data underlying the findings are fully available.\u003c/p\u003e\n\u003cp\u003eCode availability:\u0026nbsp;Not applicable.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions: All authors contributed significantly to the work and agree with the manuscript content. GT, NT, \u0026Epsilon;\u0026Beta; and \u0026Iota;\u0026Mu; were responsible for writing and design; CK, CT, and AK performed analysis and interpretation; AK provided writing and overall monitoring. All authors approved the final version.\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePage RL, Joglar JA, Caldwell MA, Calkins H, Conti JB, Deal BJ, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2016;133(14):e471\u0026ndash;505. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jacc.2015.08.856\u003c/span\u003e\u003cspan address=\"10.1016/j.jacc.2015.08.856\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBlomstr\u0026ouml;m-Lundqvist C, Scheinman MM, Aliot EM, Alpert JS, Calkins H, Camm AJ, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias\u0026mdash;executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines. J Am Coll Cardiol. 2003;42(8):1493\u0026ndash;531. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jacc.2003.08.013\u003c/span\u003e\u003cspan address=\"10.1016/j.jacc.2003.08.013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScheinman M, Calkins H, Gillette P, Klein R, Lerman BB, Morady F, et al. NASPE policy statement on catheter ablation: personnel, policy, procedures, and therapeutic recommendations. Pacing Clin Electrophysiol. 2003;26(3):789\u0026ndash;99. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1046/j.1460-9592.2003.00139.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1460-9592.2003.00139.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFriedrich MG, Sechtem U, Schulz-Menger J, Holmvang G, Alakija P, Cooper LT, et al. Cardiovascular magnetic resonance in myocarditis: A JACC White Paper. J Am Coll Cardiol. 2009;53(17):1475\u0026ndash;87. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jacc.2009.02.007\u003c/span\u003e\u003cspan address=\"10.1016/j.jacc.2009.02.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaforio AL, Pankuweit S, Arbustini E, Basso C, Gimeno-Blanes J, Felix SB, et al. Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases. Eur Heart J. 2013;34(33):2636\u0026ndash;48. 48a-48d.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCalkins H, Kuck KH, Cappato R, Brugada J, Camm AJ, Chen SA, 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. Europace. 2012;14(4):528\u0026ndash;606. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/europace/eus027\u003c/span\u003e\u003cspan address=\"10.1093/europace/eus027\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen SA, Tai CT. Ablation of atrioventricular accessory pathways: current technique-state of the art. Pacing Clin Electrophysiol. 2001;24(12):1795\u0026ndash;809. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1046/j.1460-9592.2001.01795.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1460-9592.2001.01795.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCooper LT. Jr. Myocarditis. N Engl J Med. 2009;360(15):1526\u0026ndash;38. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMra0800028\u003c/span\u003e\u003cspan address=\"10.1056/NEJMra0800028\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Atrial Fibrillation, Wolff-Parkinson-White Syndrome, Myocarditis, Catheter Ablation, High-Density Mapping, Case Report","lastPublishedDoi":"10.21203/rs.3.rs-9418000/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9418000/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe coexistence of Wolff-Parkinson-White (WPW) syndrome and Atrial Fibrillation (AF) presents a significant risk for hemodynamic collapse and sudden cardiac death.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe describe the case of a 21-year-old patient presenting with pre-excited AF and significantly elevated troponin levels. Cardiac Magnetic Resonance (CMR) imaging suggested focal myocarditis. High-density mapping using an \"Open Window\" configuration was utilized to successfully localize and ablate a left lateral accessory pathway.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis case highlights the diagnostic challenge of differentiating primary myocarditis from tachycardia-mediated myocardial injury and demonstrates the utility of high-density mapping using an \"Open Window\" configuration to facilitate successful ablation.\u003c/p\u003e","manuscriptTitle":"A complex Case of Wolff-Parkinson-White Syndrome, Atrial Fibrillation and Myocarditis: A Unique Clinical Intersection and the Utility of Open Window Mapping in Ablation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-29 11:49:10","doi":"10.21203/rs.3.rs-9418000/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"682935ef-ca6e-4438-ba9b-1c4d3752f377","owner":[],"postedDate":"April 29th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-07T12:55:01+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-04T07:26:35+00:00","index":40,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-02T06:31:00+00:00","index":39,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-01T20:38:14+00:00","index":38,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-07T13:11:36+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-29 11:49:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9418000","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9418000","identity":"rs-9418000","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}