Case Report: Double Sequential Synchronized Cardioversion for Refractory arrhythmia- A case study from Accident and Emergency Department, Lautoka Hospital, Fiji

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Macalinao, George Tabepuda, Bharatvansh Kumar Bali This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7084485/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Nov, 2025 Read the published version in Journal of Cardiology Research and Endovascular Therapy → Version 1 posted You are reading this latest preprint version Abstract Wide complex tachycardia (WCT) can potentially be a life-threatening condition that poses significant challenges in management. Here we present a case of a 57-year-old itaukei male who presented with wide complex tachycardia. Despite the use of pharmacological treatment including Amiodarone, the tachycardia persisted. Multiple synchronized cardioversions attempt with various pads positions failed to cardiovert the patient. This refractory arrhythmia was then terminated using a Double sequential synchronized cardioversion (DSSC). This case highlights the indication and appropriate technique for DSSC in managing refractory arrhythmia in an unstable patient. We review the literature regarding appropriate use of DSSC. Wide complex tachycardia (WCT) Double sequential synchronized cardioversion (DSSC) Pre-excited Atrial Fibrillation (Pre-excited AF) Ventricular tachycardia (VT) Figures Figure 1 Figure 2 Figure 3 Introduction Wide complex tachycardia is generally presumed to be ventricular tachycardia (VT) and is frequently associated with hemodynamic instability. Hence, expeditious termination of tachycardia using pharmacological or non-pharmacological means is critical and could be lifesaving. In patients who develop hemodynamic instability, synchronized electrical cardioversion is recommended as per ACC/AHA/HRS guidelines. While synchronized cardioversion succeeds in overwhelming majority of cases in terminating the tachycardia, there are situations where it fails, and these situations present difficult situations for the medical team. We present a case of a 57-year-old male who presented with cardioversion refractory arrhythmia. AHA/ACC/HRS guidelines 2017 [ 1 – 2 ] defines Ventricular tachycardia as cardiac arrhythmia of ≥ 3 consecutive complexes originating in the ventricles at a rate > 100 bpm (cycle length: 30 s or requiring termination due to hemodynamic compromise in < 30 s Nonsustained/Unsustained ≥ 3 beats, terminating spontaneously Monomorphic Stable single QRS morphology from beat to beat Polymorphic Changing or multiform QRS morphology from beat to beat Bidirectional VT with a beat-to-beat alternation in the QRS frontal plane axis, often seen in the setting of digitalis toxicity or catecholaminergic polymorphic VT Ventricular tachycardia (VT) is a potentially lethal wide complex tachy-arrhythmia that requires emergency management to prevent hemodynamic instability. Earlier research in 1962, for the treatment of shockable cardiac arrythmias of this modern resuscitation, Bernard Lown et al [ 3 ] and colleagues reported the use of direct current synchronized capacitor for treating shockable cardiac arrythmias. Synchronized cardioversion involves the delivering of energy to the QRS complex to reduce the possibility of inducing ventricular fibrillation whereas defibrillation delivers non-synchronized shocks during the cardiac cycle. Synchronization to prevent this complication is recommended for hemodynamically stable wide-complex tachycardia requiring cardioversion, supraventricular tachycardia, atrial fibrillation, and atrial flutter. [ 4 ] Double sequential synchronized cardioversion (DSSC), a technique involving simultaneous shocks from two defibrillators, has emerged as an alternative therapy for refractory cases. It involves delivering simultaneous shocks from two defibrillators, which may increase the likelihood of terminating the arrhythmia by depolarizing the myocardium, but the exact mechanism is unknown. This case report describes the successful use of DSSC in a hemodynamically unstable patient with refractory wide complex tachycardia at Lautoka hospital, after multiple shocks emphasizing its role in emergency settings. Case Presentation Patient Information : A 57-year-old itaukei male presented to our emergency department with palpitations that began while driving. The patient did not experience headache, syncope, diaphoresis, fever, chest pain or shortness of breath. He had previous instances of tachycardia and had been prescribed Aspirin 100mg PO OD, Metoprolol 25mg PO BD, Atorvastatin 4mg PO nocte and amiodarone 200mg PO OD. The patient was compliant with the medicines. Prior to presenting to the emergency department, Valsalva maneuver was attempted without success. On presentations, the patient had Blood pressure of 111/85 mmHg, heart rate (HR) 141 bpm, oxygen saturation (SpO2) 99% on room air, afebrile. On examination, he was found to be alert and awake, with no respiratory distress. Lung fields were clear with a soft and non-tender abdomen. Extremities were well-perfused extremities with good volume pulses. Complete blood count and blood chemistry was normal Initial ECG demonstrated irregular, wide complex tachycardia with positive concordance in the precordial leads (Fig. 1 ). The irregularity of the rhythm with no decipherable P waves led to possible diagnosis of pre-excited AF, especially considering previous history of arrhythmias. The patient was loaded with IV Amiodarone 300mg in the bolus form administered over 10 minutes while being attached to defibrillation pads. Magnesium sulfate was also administered in an attempt to chemically cardiovert the patient. Cardiologist was consulted and due to refractory arrhythmia, plans for DSSC under procedural sedation was made with informed consent from the patient. Preparation : Two Mindray Beneheart D3 defibrillators (Photograph 2) were used with four pads placed: the first set at the right upper chest and left lower lateral chest wall, and the second set at the left upper chest and left posterior chest. (Fig. 2 and photograph 1) Preparation for airway support was available at the bedside. Below is an example of how we placed the two sets of defibrillation pads that was similar to Sheikh H et al. (2018) [ 5 ] First Cardioversion Transient normal sinus rhythm (NSR) followed by WCT at 160 bpm. After 10 minutes a Second Cardioversion was performed with successful conversion to normal sinus rhythm at 60 bpm ( Fig. 3 ). ECG was obtained which showed negative delta wave in the inferior leads, likely right posteroseptal pathway. In retrospect, the QRS complex matches with delta wave and hence the wide complex tachycardia was pre-excited AF. After 30mins of cardiac monitoring the patient was alert and aware. He was hemodynamically stable. He had a troponin II of 24, cholesterol panel and thyroid function test was normal. A chest Xray showed the heart was slightly enlarged with a cardiothoracic ratio (CTR) 17/31. His inpatient Echogram showed a normal ejection fraction of 55% with no regional wall motion abnormalities and no valvular abnormalities. He was discharged with Flecainide 100mg twice a day along with Metoprolol 50mg twice a day. He was scheduled for electrophysiology study (EPS) +/- ablation at tertiary care center. Discussion The important components of the acute management of wide complex tachycardia is to stabilize the patient hemodynamically. In our patient, the wide complex tachycardia diagnosed to be pre-excited was refractory to Valsalva maneuvers, Amiodarone as well as electrical cardioversion with pads positioned in various configurations. However, we were able to successfully cardiovert the patient using DSSC. Our case presents a rare situation of refractory arrhythmia, which is critical to recognize and manage using DSSC. Previous studies have reported similar successful use of DSSC for treatment of refractory hemodynamically unstable ventricular tachycardia after multiple cardioversions failed. Sheikh H et al report (5) a case of a patient with monomorphic VT on arrival with multiple attempts at electrical cardioversion and escalated to a successful double sequential 200J synchronized shocks. Kamil et al report (6) had a patient who was unstable and received multiple synchronized cardioversions with amiodarone administered after the third shock. DSSC was eventually used to successfully cardiovert this patient. Our patient did not present with ventricular tachycardia but exhibited pre-excited atrial fibrillation, which manifested as episodes of wide complex tachycardia. He became hemodynamically unstable during the administration of amiodarone as a loading dose and multiple synchronized cardioversion attempts including vector changes with various patch configuration. We successfully achieved normal sinus rhythm after two attempts of DSSC with no major adverse events reported, highlighting its potential as an intervention although it has not been evidently studied. Conclusion Double Sequential Synchronized defibrillation has been previously used for refractory pulseless VT/ventricular fibrillation as a last resort when the standard protocol fails. We present a unique case of pre-excited AF with a pulse successfully cardioverted with DSSC using similar technique as described previously for ventricular arrhythmia. DSSC had been used with success in patients with AF as well with neither study reported major complication [ 7 , 8 ]. Our case underscores the importance of considering DSSC in this clinical scenario and highlights the need for further research to establish standardized protocols and guidelines for its use. Abbreviations Wide complex tachycardia (WCT), Ventricular tachycardia (VT) Double sequential synchronized cardioversion (DSSC), Atrial fibrillation (AF), cardiothoracic ratio (CTR), electrophysiology study (EPS) Declarations Contributions All authors were actively involved in the clinical management of the patient and contributed to the development of this case report. K.G.G.M. drafted the initial manuscript and led subsequent revisions. G.T. provided critical evaluation of the first draft, offering constructive feedback and recommendations on proper citation practices. All authors participated in the critical review, revision, and final approval of the manuscript. B.K.B. supervised the final manuscript preparation and coordinated with the acknowledged individual for editorial support. Consent to Publish declaration The patient gave us informed and signed consent for his photographs, images, and medical information for publication. Ethics declarations Ethical approval This case report does not contain data pertaining to any studies with human participants or animals, performed by any of the authors. Approved by Fiji Human Health Research and Ethics Review Committee and Lautoka Hospital for this case publication. Conflict of interests Authors declare no conflict of interest. Funding Declaration This case report received no specific funding Acknowledgement I would like to express my sincere gratitude to Dr. Jignesh Shah MD. Cardiology Consultants, LLC for his invaluable assistance in editing this case report. Additionally, I extend my appreciation to RN Sera Rokonai and Loata Bogidrau for their continuous monitoring of this patient. I am also grateful to the Pacing Islands Pacemaker Services, EP cardiologists for their expertise, and to the internal medicine consultant, Dr. Lalit Kumar, along with his team, for their exceptional inpatient care. Verbal and written consent was obtained from all individuals acknowledged in this manuscript. References Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM. 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Journal of the American College of Cardiology. 2018 Oct 2;72(14): e91-220. [Google Scholar] Buxton AE, Calkins H, Callans DJ, DiMarco JP, Fisher JD, Leon Greene H, Haines DE, Hayes DL, Heidenreich PA, Miller JM, Poppas A. ACC/AHA/HRS 2006 key data elements and definitions for electrophysiological studies and procedures: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Data Standards (ACC/AHA/HRS Writing Committee to Develop Data Standards on Electrophysiology). Journal of the American College of Cardiology. 2006 Dec 5;48(11):2360-96. [Google Scholar] Lown B, Amarasingham R, Neuman J. New method for terminating cardiac arrhythmias. Use of synchronized capacitor discharge. Jama. 1962 Nov 1;182:548-55. [Google Scholar] American Heart Association. Synchronization to prevent this complication is recommended for hemodynamically stable wide-complex tachycardia requiring cardioversion, supraventricular tachycardia, atrial fibrillation, and atrial flutter [Internet]. Circulation . 2000;102(Suppl 1):I-90. Available from: https://www.ahajournals.org/doi/10.1161/circ.102.suppl_1.I-90 Sheikh H, Xie E, Austin E. Double sequential cardioversion for refractory ventricular tachycardia: A case report. CJEM. 2018;20(S2):S56–60. doi:10.1017/cem.2017.428 [Google Scholar] Kamil MK, Othman NN, Aziz MA, Ismail SA. Double Sequential Synchronized Cardioversion for Refractory Unstable Ventricular Tachycardia: A case report [Google Scholar] Rodríguez EV, Enríquez AM, Rodríguez CC, Morales GO, Rojo JR, Estrada SA. Double sequential electrical transthoracic shocks for refractory atrial fibrillation. Archivos de cardiología de México. 2005;75(S3):69-80. [Google Scholar] Kabukcu M, Demircioglu F, Yanik E, Minareci K, Ersel-Tüzüner F. Simultaneous double external DC shock technique for refractory atrial fibrillation in concomitant heart disease. Japanese heart journal. 2004;45(6):929-36. [Google Scholar] Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 16 Nov, 2025 Read the published version in Journal of Cardiology Research and Endovascular Therapy → 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7084485","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":503873371,"identity":"3f55ab24-cf27-4fbd-8630-063165bf7b19","order_by":0,"name":"Kim Gerome G. Macalinao","email":"data:image/png;base64,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","orcid":"","institution":"Lautoka Hospital","correspondingAuthor":true,"prefix":"","firstName":"Kim","middleName":"Gerome G.","lastName":"Macalinao","suffix":""},{"id":503873372,"identity":"1cd62fcf-2256-4dcf-818e-d117b8fd56e8","order_by":1,"name":"George Tabepuda","email":"","orcid":"","institution":"Lautoka Hospital","correspondingAuthor":false,"prefix":"","firstName":"George","middleName":"","lastName":"Tabepuda","suffix":""},{"id":503873373,"identity":"3bac539f-f7ea-4a8c-903b-6b00cdb06bba","order_by":2,"name":"Bharatvansh Kumar Bali","email":"","orcid":"","institution":"Lautoka Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bharatvansh","middleName":"Kumar","lastName":"Bali","suffix":""}],"badges":[],"createdAt":"2025-07-09 14:08:17","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7084485/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7084485/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.66311/3068-9171.01.02.05","type":"published","date":"2025-11-17T00:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89978839,"identity":"38ab5eca-d5b7-450b-be61-09032cdc1d69","added_by":"auto","created_at":"2025-08-27 06:16:29","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":149963,"visible":true,"origin":"","legend":"\u003cp\u003eThe patient’s blood pressure dropped after these pharmacological interventions prompting further emergent intervention. Synchronized cardioversion was attempted at escalating energies (50J, 100J, 150J, 200J) under sedation without success. Vector change with pads transferred from the standard anterior-lateral to the \u003cstrong\u003eanterior-posterior position \u003c/strong\u003etrialed for cardioversion but was unsuccessful.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7084485/v1/45548267323b079b870809bd.jpg"},{"id":89978843,"identity":"19654e65-a6e1-4a7c-8084-7ff7a2760011","added_by":"auto","created_at":"2025-08-27 06:16:30","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":145485,"visible":true,"origin":"","legend":"\u003cp\u003eMorphine 2.5mg IV and Midazolam 5mg IV were administered. Supportive 02 via rebreather was given. \u003cstrong\u003eProcedure:\u003c/strong\u003e Synchronized shocks at 200J were delivered simultaneously from both defibrillators with a single person pressing image.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7084485/v1/5236d1cef98a73ccdde394ff.jpg"},{"id":89978819,"identity":"17323b04-8cba-4115-b4fb-74ec1a3dd8dc","added_by":"auto","created_at":"2025-08-27 06:16:28","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":111577,"visible":true,"origin":"","legend":"\u003cp\u003eNormal sinus rhythm with delta waves and Q waves in leads III and AVF.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7084485/v1/dbc418f51c75df485914e8f4.jpg"},{"id":105904150,"identity":"37e27693-0cca-44b6-ad42-1de9db75032c","added_by":"auto","created_at":"2026-04-01 10:05:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1532215,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7084485/v1/daba8cea-fa82-45e8-a958-b3e932267776.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Case Report: Double Sequential Synchronized Cardioversion for Refractory arrhythmia- A case study from Accident and Emergency Department, Lautoka Hospital, Fiji","fulltext":[{"header":"Introduction","content":"\u003cp\u003e\u003cb\u003eWide complex tachycardia is generally presumed to be ventricular tachycardia (VT) and is frequently associated with hemodynamic instability. Hence, expeditious termination of tachycardia using pharmacological or non-pharmacological means is critical and could be lifesaving. In patients who develop hemodynamic instability, synchronized electrical cardioversion is recommended as per ACC/AHA/HRS guidelines. While synchronized cardioversion succeeds in overwhelming majority of cases in terminating the tachycardia, there are situations where it fails, and these situations present difficult situations for the medical team.\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eWe present a case of a 57-year-old male who presented with cardioversion refractory arrhythmia.\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eAHA/ACC/HRS guidelines 2017\u003c/span\u003e [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] defines Ventricular tachycardia as \u003cem\u003ecardiac arrhythmia of ≥ 3 consecutive complexes originating in the ventricles at a rate \u0026gt; 100 bpm (cycle length: \u0026lt;600ms). Below are the types of VT defined as well\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv class=\"gridtable\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eSustained: VT\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003e\u0026gt; 30 s or requiring termination due to hemodynamic compromise in \u0026lt; 30 s\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eNonsustained/Unsustained\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003e≥ 3 beats, terminating spontaneously\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eMonomorphic\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eStable single QRS morphology from beat to beat\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003ePolymorphic\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eChanging or multiform QRS morphology from beat to beat\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eBidirectional\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eVT with a beat-to-beat alternation in the QRS frontal plane axis, often seen in the setting of digitalis toxicity or catecholaminergic polymorphic VT\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eVentricular tachycardia (VT) is a potentially lethal wide complex tachy-arrhythmia that requires emergency management to prevent hemodynamic instability. Earlier research in 1962, for the treatment of shockable cardiac arrythmias of this modern resuscitation, \u003cem\u003eBernard Lown et al\u003c/em\u003e [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] \u003cem\u003eand colleagues\u003c/em\u003e reported the use of direct current synchronized capacitor for treating shockable cardiac arrythmias.\u003c/p\u003e\u003cp\u003eSynchronized cardioversion involves the delivering of energy to the QRS complex to reduce the possibility of inducing ventricular fibrillation whereas defibrillation delivers non-synchronized shocks during the cardiac cycle. \u003cem\u003eSynchronization to prevent this complication is recommended for hemodynamically stable wide-complex tachycardia requiring cardioversion, supraventricular tachycardia, atrial fibrillation, and atrial flutter.\u003c/em\u003e [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eDouble sequential synchronized cardioversion (DSSC), a technique involving simultaneous shocks from two defibrillators, has emerged as an alternative therapy for refractory cases. It involves delivering simultaneous shocks from two defibrillators, which may increase the likelihood of terminating the arrhythmia by depolarizing the myocardium, but the exact mechanism is unknown.\u003c/p\u003e\u003cp\u003eThis case report describes the successful use of DSSC in a hemodynamically unstable patient with refractory wide complex tachycardia at Lautoka hospital, after multiple shocks emphasizing its role in emergency settings.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003ePatient Information\u003c/span\u003e:\u003c/p\u003e\u003cp\u003eA 57-year-old itaukei male presented to our emergency department with palpitations that began while driving. The patient did not experience headache, syncope, diaphoresis, fever, chest pain or shortness of breath. He had previous instances of tachycardia and had been prescribed Aspirin 100mg PO OD, Metoprolol 25mg PO BD, Atorvastatin 4mg PO nocte and amiodarone 200mg PO OD. The patient was compliant with the medicines. Prior to presenting to the emergency department, Valsalva maneuver was attempted without success.\u003c/p\u003e\u003cp\u003eOn presentations, the patient had Blood pressure of 111/85 mmHg, heart rate (HR) 141 bpm, oxygen saturation (SpO2) 99% on room air, afebrile. On examination, he was found to be alert and awake, with no respiratory distress. Lung fields were clear with a soft and non-tender abdomen. Extremities were well-perfused extremities with good volume pulses. Complete blood count and blood chemistry was normal\u003c/p\u003e\u003cp\u003eInitial ECG demonstrated irregular, wide complex tachycardia with positive concordance in the precordial leads (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The irregularity of the rhythm with no decipherable P waves led to possible diagnosis of pre-excited AF, especially considering previous history of arrhythmias. The patient was loaded with IV Amiodarone 300mg in the bolus form administered over 10 minutes while being attached to defibrillation pads. Magnesium sulfate was also administered in an attempt to chemically cardiovert the patient.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCardiologist was consulted and due to refractory arrhythmia, plans for DSSC under procedural sedation was made with informed consent from the patient.\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003ePreparation\u003c/b\u003e: Two Mindray Beneheart D3 defibrillators (Photograph 2) were used with four pads placed: the first set at the right upper chest and left lower lateral chest wall, and the second set at the left upper chest and left posterior chest. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and photograph 1) Preparation for airway support was available at the bedside. \u003cb\u003eBelow is an example of how we placed the two sets of defibrillation pads that was similar to Sheikh H et al. (2018)\u003c/b\u003e [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eFirst Cardioversion\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eTransient normal sinus rhythm (NSR) followed by WCT at 160 bpm.\u003c/p\u003e\u003cp\u003eAfter 10 minutes a \u003cb\u003eSecond Cardioversion was performed with successful conversion to normal sinus rhythm at 60 bpm (\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e ECG was obtained which showed negative delta wave in the inferior leads, likely right posteroseptal pathway. In retrospect, the QRS complex matches with delta wave and hence the wide complex tachycardia was pre-excited AF.\u003c/p\u003e\u003cp\u003eAfter 30mins of cardiac monitoring the patient was alert and aware. He was hemodynamically stable. He had a troponin II of 24, cholesterol panel and thyroid function test was normal. A chest Xray showed the heart was slightly enlarged with a cardiothoracic ratio (CTR) 17/31. His inpatient Echogram showed a normal ejection fraction of 55% with no regional wall motion abnormalities and no valvular abnormalities. He was discharged with Flecainide 100mg twice a day along with Metoprolol 50mg twice a day. He was scheduled for electrophysiology study (EPS) +/- ablation at tertiary care center.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe important components of the acute management of wide complex tachycardia is to stabilize the patient hemodynamically. In our patient, the wide complex tachycardia diagnosed to be pre-excited was refractory to Valsalva maneuvers, Amiodarone as well as electrical cardioversion with pads positioned in various configurations. However, we were able to successfully cardiovert the patient using DSSC. Our case presents a rare situation of refractory arrhythmia, which is critical to recognize and manage using DSSC.\u003c/p\u003e\u003cp\u003ePrevious studies have reported similar successful use of DSSC for treatment of refractory hemodynamically unstable ventricular tachycardia after multiple cardioversions failed. Sheikh H et al report \u003cb\u003e(5)\u003c/b\u003e a case of a patient with monomorphic VT on arrival with multiple attempts at electrical cardioversion and escalated to a successful double sequential 200J synchronized shocks. Kamil et al report \u003cb\u003e(6)\u003c/b\u003e had a patient who was unstable and received multiple synchronized cardioversions with amiodarone administered after the third shock. DSSC was eventually used to successfully cardiovert this patient.\u003c/p\u003e\u003cp\u003eOur patient did not present with ventricular tachycardia but exhibited pre-excited atrial fibrillation, which manifested as episodes of wide complex tachycardia. He became hemodynamically unstable during the administration of amiodarone as a loading dose and multiple synchronized cardioversion attempts including vector changes with various patch configuration.\u003c/p\u003e\u003cp\u003eWe successfully achieved normal sinus rhythm after two attempts of DSSC with no major adverse events reported, highlighting its potential as an intervention although it has not been evidently studied.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eDouble Sequential Synchronized defibrillation has been previously used for refractory pulseless VT/ventricular fibrillation as a last resort when the standard protocol fails. We present a unique case of pre-excited AF with a pulse successfully cardioverted with DSSC using similar technique as described previously for ventricular arrhythmia. DSSC had been used with success in patients with AF as well with neither study reported major complication [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Our case underscores the importance of considering DSSC in this clinical scenario and highlights the need for further research to establish standardized protocols and guidelines for its use.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eWide complex tachycardia (WCT), Ventricular tachycardia (VT) Double sequential synchronized cardioversion (DSSC), Atrial fibrillation (AF), cardiothoracic ratio (CTR), electrophysiology study (EPS)\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cu\u003eContributions\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors were actively involved in the clinical management of the patient and contributed to the development of this case report. K.G.G.M. drafted the initial manuscript and led subsequent revisions. G.T. provided critical evaluation of the first draft, offering constructive feedback and recommendations on proper citation practices. All authors participated in the critical review, revision, and final approval of the manuscript. B.K.B. supervised the final manuscript preparation and coordinated with the acknowledged individual for editorial support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eConsent to Publish declaration\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe patient gave us informed and signed consent for his photographs, images, and medical information for publication.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eEthics declarations\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eEthical approval\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis case report does not contain data pertaining to any studies with human participants or animals, performed by any of the authors. Approved by \u003cstrong\u003e\u003cem\u003eFiji Human Health Research and Ethics Review Committee and Lautoka Hospital\u0026nbsp;\u003c/em\u003e\u003c/strong\u003efor this case publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eConflict of interests\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eFunding Declaration\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis case report received no specific funding\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eAcknowledgement\u0026nbsp;\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI would like to express my sincere gratitude to Dr. Jignesh Shah MD. Cardiology Consultants, LLC for his invaluable assistance in editing this case report. Additionally, I extend my appreciation to RN Sera Rokonai and Loata Bogidrau for their continuous monitoring of this patient. I am also grateful to the Pacing Islands Pacemaker Services, EP cardiologists for their expertise, and to the internal medicine consultant, Dr. Lalit Kumar, along with his team, for their exceptional inpatient care. Verbal and written consent was obtained from all individuals acknowledged in this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAl-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, Gillis AM. 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Journal of the American College of Cardiology. 2018 Oct 2;72(14): e91-220. 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[Google Scholar]\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"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":"Wide complex tachycardia (WCT), Double sequential synchronized cardioversion (DSSC), Pre-excited Atrial Fibrillation (Pre-excited AF), Ventricular tachycardia (VT)","lastPublishedDoi":"10.21203/rs.3.rs-7084485/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7084485/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWide complex tachycardia (WCT) can potentially be a life-threatening condition that poses significant challenges in management. Here \u003cb\u003ewe present a case of a 57-year-old itaukei male who presented with wide complex tachycardia. Despite the use of pharmacological treatment including Amiodarone, the tachycardia persisted. Multiple synchronized cardioversions attempt with various pads positions failed to cardiovert the patient. This refractory arrhythmia was then terminated using a Double sequential synchronized cardioversion (DSSC).\u003c/b\u003e This case highlights the indication and appropriate technique for DSSC in managing refractory arrhythmia in an unstable patient. We review the literature regarding appropriate use of DSSC.\u003c/p\u003e","manuscriptTitle":"Case Report: Double Sequential Synchronized Cardioversion for Refractory arrhythmia- A case study from Accident and Emergency Department, Lautoka Hospital, Fiji","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-27 06:16:24","doi":"10.21203/rs.3.rs-7084485/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":"49890a5a-c247-4c23-bd5e-22789dc06bed","owner":[],"postedDate":"August 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-30T16:08:08+00:00","versionOfRecord":{"articleIdentity":"rs-7084485","link":"https://doi.org/10.66311/3068-9171.01.02.05","journal":{"identity":"journal-of-cardiology-research-and-endovascular-therapy","isVorOnly":true,"title":"Journal of Cardiology Research and Endovascular Therapy"},"publishedOn":"2025-11-17 00:00:00","publishedOnDateReadable":"November 17th, 2025"},"versionCreatedAt":"2025-08-27 06:16:24","video":"","vorDoi":"10.66311/3068-9171.01.02.05","vorDoiUrl":"https://doi.org/10.66311/3068-9171.01.02.05","workflowStages":[]},"version":"v1","identity":"rs-7084485","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7084485","identity":"rs-7084485","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}