{"paper_id":"3d9bcda2-e509-425a-9031-68b3a91a7d61","body_text":"Tricuspid Valve Infective Endocarditis Caused by ESBL Producing E.coli Complicated by Symptomatic AV block Requiring Temporary Epicardial Pacing: A Case Report | 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 Tricuspid Valve Infective Endocarditis Caused by ESBL Producing E.coli Complicated by Symptomatic AV block Requiring Temporary Epicardial Pacing: A Case Report Roben Ohev Shalom, Saro Avedikian, Victoria Watkins, Manraj Johal, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9163653/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Background : Infective endocarditis (IE) caused by non-HACEK gram-negative organisms is rare, accounting for fewer than 2% of cases, and endocarditis due to extended-spectrum β-lactamase (ESBL)–producing Escherichia coli is exceptionally uncommon. Right-sided involvement, particularly isolated tricuspid valve infective endocarditis (TVIE), and associated atrioventricular (AV) conduction abnormalities are rarely reported, creating diagnostic and management challenges, especially when pacing is required. Case Presentation: A 75-year-old Caucasian man with pre-existing right bundle branch block presented with syncope shortly after hospitalization for ESBL E. coli bacteremia treated with intravenous ertapenem. Electrocardiography revealed progressive AV conduction delay with intermittent high-degree AV block. Transthoracic echocardiography was nondiagnostic, while transesophageal echocardiography identified a tricuspid valve vegetation without abscess. Given active infective endocarditis and symptomatic conduction disease, transvenous pacing was contraindicated. The patient underwent urgent placement of a temporary epicardial ventricular lead, resulting in hemodynamic stabilization. He completed a six-week course of ertapenem with subsequent resolution of the tricuspid valve vegetation on follow-up imaging. After infection clearance, a transvenous dual-chamber pacemaker was successfully implanted. Conclusions : This case highlights a rare presentation of ESBL-producing E. coli TVIE complicated by advanced AV block. It underscores the importance of early transesophageal imaging in suspected right-sided endocarditis, awareness of conduction disturbances as a marker of disease severity, and the role of epicardial pacing as a safe bridging strategy when permanent transvenous systems are contraindicated during active infection. Tricuspid Valve Infective Endocarditis ESBL E.coli AV block epicardial pacing Figures Figure 1 Figure 2 Figure 3 Figure 4 Background ​​Infective endocarditis (IE) is most commonly caused by gram-positive organisms, particularly Staphylococcus aureus and viridans group streptococci, while gram-negative bacteria remain an uncommon etiology. In a large prospective multinational cohort, non-HACEK gram-negative bacilli accounted for only 1.8% of all definite IE cases, underscoring the rarity of these infections in contemporary practice.[ 1 ] Within this already small subset, endocarditis caused by extended-spectrum β-lactamase (ESBL)–producing organisms is exceptionally rare, with only sporadic case reports described in the literature.[ 2 – 4 ] This rarity contributes to diagnostic uncertainty and a lack of standardized management strategies, particularly when complicated by atypical features such as conduction system disease. ESBL-producing Escherichia coli has emerged as a significant cause of bloodstream infection, especially among older adults with healthcare exposure [ 5 ]; however, its ability to cause native valve endocarditis remains poorly understood.[ 2 ] Reported cases of ESBL-associated IE most commonly involve left-sided valves, particularly the mitral valve, and are frequently complicated by embolic events or require surgical intervention.[ 2 , 6 ] Right-sided involvement, particularly isolated tricuspid valve endocarditis, is far less frequently reported, making the present case notable both for valve location and for its associated conduction abnormality. Infective endocarditis involving the tricuspid valve presents unique management challenges, particularly in patients with underlying conduction system disease who are also symptomatic and require pacing. Transvenous pacemaker implantation is generally contraindicated in the setting of active endocardial infection due to the risk of persistent or recurrent infection. As a result, alternative pacing strategies must be considered, including epicardial lead placement. While epicardial pacing is well described in select surgical populations [ 16 ], its role in patients with right-sided infective endocarditis and brady-arrhythmias remains less commonly reported. We present a case of tricuspid valve infective endocarditis complicated by advanced conduction disease, necessitating epicardial pacemaker implantation, followed by subsequent transition to a transvenous dual-chamber system after infection resolution. Case presentation A 75-year-old Caucasian male with pre-existing right bundle branch block and one year history of Whipple procedure with biliary stent placement presented four days after discharge from a recent hospitalization for sepsis due to extended-spectrum β-lactamase (ESBL) Escherichia coli bacteremia, treated with intravenous ertapenem. He reported dizziness following a syncopal episode that occurred while sitting in the passenger seat of his car. The loss of consciousness lasted approximately 30 seconds and was preceded by visual changes and mild dizziness. The patient otherwise led an active lifestyle, regularly playing golf, and had no other acute complaints. On examination, he was hemodynamically stable with normal vital signs. Cardiac evaluation revealed a regular rate and rhythm, without murmurs, rubs, or gallops. Pulmonary examination was unremarkable. Electrocardiography demonstrated sinus bradycardia with first-degree atrioventricular (AV) block and intermittent pauses, left axis deviation, and pre-existing right bundle branch block ( Fig. 1 ). Telemetry monitoring revealed intermittent high-degree AV block. Laboratory evaluation revealed normal white blood cell count and hemoglobin. Central metabolic panel notable for slight hyperkalemia (potassium of 5.3) and mildly elevated hepatic enzymes (Aspartate Aminotransferase 40, Alkaline Phosphatase 130) with preserved renal function. Blood cultures at this presentation were negative, however were positive for ESBL E. coli in admission one week prior. Transthoracic echocardiogram (TTE) demonstrated normal left ventricular function without valvular abnormalities; however, the tricuspid valve was poorly visualized. Subsequent transesophageal echocardiogram (TEE) revealed a mobile mass sitting on tricuspid valve, close to septum, about 1 cm long with flagellating distal end on atrial side of the valve with no evidence of abscess formation. Mild tricuspid regurgitation was also noted ( Fig. 2 ). Differential diagnosis for his syncope included cardiac causes (progressive AV block), dehydration, neurological etiologies, and medication-related adverse effects (ertapenem). Contributing factors for AV block included age-related degenerative disease, coronary ischemia, and metabolic derangements such as hyperkalemia or hypothyroidism. Investigations from his prior admission revealed ESBL bacteremia in both aerobic and anaerobic cultures, with sensitivity to meropenem and piperacillin-tazobactam. Infectious disease consultation at that time failed to identify a definitive source; urinalysis was normal. Bacteremia was attributed to mild cholangitis with polymicrobial bloodstream infection. Due to the persistence of his symptoms, he was admitted to the cardiac care unit and started on an isoproterenol infusion. Given the contraindication of transvenous right ventricular pacemaker placement in active infective endocarditis, cardiothoracic surgery performed urgent placement of a temporary epicardial ventricular lead via mini-thoracotomy ( Fig. 3 a ). The lead was tunneled to a left subpectoral pocket containing a dual-chamber pacemaker, with the atrial lead intentionally capped. The patient experienced improved hemodynamic and mental status post-procedure, with only mild surgical-site pain. The post-operative course was complicated by left pleural effusion and atelectasis, which was resolved with supportive management and continuation of intravenous antibiotics. The patient completed a six-week course of ertapenem and was discharged with close outpatient follow-up. One month later, repeat TEE demonstrated complete resolution of the tricuspid valve vegetation. At that time, new endocardial atrial and ventricular leads were placed, converting the system to a fully functional dual-chamber pacemaker ( Fig. 3 b ). Discussion Though the pathogenesis of ESBL-producing Escherichia coli endocarditis is not well understood, recent studies have aimed to characterize virulence factors within phylogenetic group B2. This group has a strong association with extraintestinal pathogenic E. coli (ExPEC), which are known to cause severe invasive infections.[ 7 ] The most notorious member of this group, E. coli clone ST131, has been identified as an emerging global threat due to its extensive repertoire of virulence and antimicrobial resistance genes.[ 8 ] Capsule formation, adhesion factors, and biofilm formation and maturation facilitate immune evasion and may create favorable conditions for the development of infective endocarditis.[ 9 ] Plasmid-associated acquired resistance genes (ARGs), such as CTX-M, as seen in our case, further limit effective antimicrobial options and may contribute to bacterial persistence. The combined presence of virulence factors and antimicrobial resistance genes presents significant challenges in clinical practice, often necessitating the use of more potent antibiotics. In this patient, the virulence and resistance profile of the organism likely contributed to persistent infection and may explain why epicardial pacing was required rather than antibiotics alone. To our knowledge, only one other case — reported by Fordyce et al — has described tricuspid valve endocarditis due to extended-spectrum β‑lactamase-producing Escherichia coli complicated by complete heart block.[ 10 ] While the Fordyce case and several other reports of TVIE complicated by atrioventricular conduction delay suggest resolution of block with antibiotics, conduction abnormalities in right-sided endocarditis remain exceedingly rare. In our patient, despite one week of appropriate antimicrobial therapy, there was progressive AV conduction delay with PR interval prolongation and intermittent pauses, including episodes of third-degree heart block. Because of his pre-existing AV nodal disease and the high virulence of ESBL endocarditis, the patient was at increased risk for irreversible conduction impairment, prompting urgent placement of a temporary epicardial pacemaker. This approach is consistent with evidence that baseline conduction delays such as first-degree AV block in infective endocarditis are associated with progression to high-degree AV block, reflecting more severe or invasive disease and justifying early pacing intervention.[ 11 ] In patients with infective endocarditis (TVIE) complicated by new or worsening atrioventricular (AV) block, surgical intervention is indicated especially if the infection is complicated by valve dysfunction, including a resistant organism, persistent infection and relapsing prosthetic valve endocarditis. [ 12 ] In aortic or mitral valve endocarditis, conduction disease strongly favors early surgical intervention due to the close anatomic relationship of these valves to the AV node within Koch’s triangle, where perivalvular infection can readily disrupt the conduction system. Conversely, the tricuspid valve is more distant from the AV node, which likely explains the rarity of atrioventricular block in tricuspid valve infective endocarditis. In this setting of right sided endocarditis, the AV block may be related to inflammatory edema or transient myocardial involvement rather than structural destruction that mandates surgical repair.[ 13 ] Case reports support that antibiotic therapy alone can lead to resolution of AV conduction disturbances in TVIE and allows surgical intervention to be deferred. For example, Martínez‑Urueña et al. described a patient with tricuspid valve vegetations and transient trifascicular block who improved with antibiotic therapy and temporary pacing, without surgical intervention.[ 14 ] Similarly, Singh and Kalathiya reported reversible complete heart block in tricuspid valve endocarditis managed successfully with antibiotics, highlighting that conduction abnormalities may resolve once inflammation and bacteremia are controlled.[ 15 ] In our reported case, the decision was made to proceed with epicardial pacing rather than continue antibiotic therapy as the patient was severely symptomatic from the arrhythmia and had baseline AV block. Surgical intervention was reserved for antibiotic failure, unlikely event of abscess formation, vegetation enlargement, recurrent embolization, or the development of right heart failure. While this case illustrates a rare clinical presentation of ESBL-producing E. coli endocarditis with conduction abnormalities, several limitations should be considered. Blood cultures were negative in this presentation; however, the patient had received daily intravenous ertapenem therapy for ESBL-producing E. coli bacteremia one week prior to admission, which may have contributed to culture negativity. A previous report described a similar scenario in which blood cultures were negative, but tissue cultures from a tricuspid valve replacement revealed ESBL-producing Escherichia coli as the causative pathogen. [ 6 ] Another limitation in our case is the patient’s pre-existing atrioventricular (AV) block. Although age-related degenerative conduction disease could have contributed to worsening AV conduction, it is notable that the patient developed third-degree AV block and progressive PR prolongation coinciding with the endocarditis. While we cannot definitively prove causation, the temporal relationship between the infection and conduction abnormalities supports the likelihood that the endocarditis contributed to the conduction disturbance, ultimately prompting the placement of an epicardial pacemaker. Conclusion This case illustrates an exceptionally rare presentation of native tricuspid valve infective endocarditis caused by ESBL-producing Escherichia coli , complicated by progressive high-degree atrioventricular block in a patient with pre-existing conduction disease. It emphasizes that new or worsening conduction abnormalities in the setting of bacteremia—particularly with virulent or resistant organisms—should prompt heightened suspicion for endocardial involvement, even when transthoracic imaging is nondiagnostic. Early transesophageal echocardiography was critical for diagnosis, and multidisciplinary decision-making allowed for timely hemodynamic stabilization using temporary epicardial pacing while avoiding the risks associated with transvenous systems during active infection. This case highlights the importance of individualized pacing strategies in infective endocarditis and reinforces that right-sided disease, though anatomically distant from the atrioventricular node, can still manifest with clinically significant conduction disturbances requiring urgent intervention. Abbreviations IE Infective Endocarditis TVIE Tricuspid Valve Infective Endocarditis ESBL Extended-Spectrum β-Lactamase E. coli Escherichia coli AV Atrioventricular TTE Transthoracic Echocardiography TEE Transesophageal Echocardiography RBBB Right Bundle Branch Block ExPEC Extraintestinal Pathogenic Escherichia coli ST131 Sequence Type 131 ARGs Antimicrobial Resistance Genes CTX-M Cefotaximase-Munich (β-lactamase enzyme family) Declarations Ethics approval and consent to participate: Not applicable. 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. Availability of data and materials: Not applicable. Competing interests: The authors declare no competing interests. Funding: The authors declare there is no funding support for this manuscript. Availability of data and materials Not applicable. Author contributions: R.O. contributed to the drafting and editing of the manuscript as well as the procurement and editing of images and obtaining of patient consent. S.A. contributed to the drafting and editing of the manuscript as well as the procurement and editing of images. V.T. contributed to the drafting and editing of the manuscript. V.W. contributed to the drafting and editing of the manuscript. M.J. contributed to the drafting and editing of the manuscript. Acknowledgements: Not applicable. This research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities. References Morpeth S, Murdoch D, Cabell CH, et al. Non-HACEK gram-negative bacillus endocarditis. Ann Intern Med . 2007;147(12):829-35. Kenzaka T, Shinkura Y, Kayama S, et al. Infective endocarditis caused by extended-spectrum β-lactamase-producing Escherichia coli: a case report. Infect Drug Resist . 2021;14:3357-62. Modi HH, Modi SH, Siddiqui BR, Andreoni JM. A rare case of prosthetic valve endocarditis caused by extended-spectrum β-lactamase producing Escherichia coli. J Glob Infect Dis . 2011;3(1):99-101. doi:10.4103/0974-777X.77310. George S, Varghese J, Chandrasekhar S, et al. Gram-negative bacteria causing infective endocarditis: rare cardiac complication after liver transplantation. World J Hepatol . 2013;5(5):296-7. doi:10.4254/wjh.v5.i5.296. Leistner R, Sakellariou C, Gürntke S, et al. Mortality and molecular epidemiology associated with extended-spectrum β-lactamase production in Escherichia coli from bloodstream infection. Infect Drug Resist . 2014;7:57-62. doi:10.2147/IDR.S56984. Saboe A, Sari MT, Cool CJ, et al. Cutaneous vasculitis and generalized lymphadenopathy associated with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli endocarditis: a rare case report. Infect Dis Ther . 2021;10(1):583-93. doi:10.1007/s40121-020-00377-4. Micenková L, Bosák J, Vrba M, Ševčíková A, Šmajs D. Human extraintestinal pathogenic Escherichia coli strains differ in prevalence of virulence factors, phylogroups, and bacteriocin determinants. BMC Microbiol . 2016;16:218. doi:10.1186/s12866-016-0835-z. Lavigne JP, Vergunst A, Goret L, et al. Virulence potential and genomic mapping of the worldwide clone Escherichia coli ST131. PLoS One . 2012;7(3):e34294. doi:10.1371/journal.pone.0034294. Flórez-Navas PC, Josa D, Silva-Monsalve E, Ballesteros N, Castañeda S, Muñoz M, et al. Infective endocarditis caused by Escherichia coli O25b:H4-B2-ST131: a case report providing genotypic, phenotypic, and phylogenetic insights. J Int Med Res . 2025;53(12):3000605251404825. doi:10.1177/03000605251404825. Fordyce C, Leather R, Partlow E, Swiggum E. Complete heart block associated with tricuspid valve endocarditis due to extended-spectrum β-lactamase-producing Escherichia coli. Can J Cardiol . 2011;27:263.e17-263.e20. Philip M, Hourdain J, Resseguier N, et al. Atrioventricular conduction disorders in aortic valve infective endocarditis: occurrence, contributing factors, prognosis and evolution. Arch Cardiovasc Dis . 2024;117(5):304-12. Nishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol . 2014;63(22):e57-185. Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F, et al. 2015 ESC guidelines for the management of infective endocarditis. Eur Heart J . 2015;36(44):3075-128. Martínez-Urueña N, Hernández C, Duro I, Sandín MG, Zatarain E, San Román A. Transient trifascicular block secondary to tricuspid valve endocarditis. Rev Esp Cardiol (Engl Ed) . 2012;65(8):767-8. Singh N, Kalathiya RJ. Transient complete heart block: a case report of a rare complication of tricuspid valve infective endocarditis. Eur Heart J Case Rep . 2021;5(8):ytab287. Gillham MJ, Barr TM. Temporary epicardial pacing after cardiac surgery. BJA Educ. 2023 Sep;23(9):337-349. doi: 10.1016/j.bjae.2023.05.003. Epub 2023 Jul 6. PMID: 37600212; PMCID: PMC10433321. Additional Declarations No competing interests reported. Supplementary Files TEEvegetationTR.mp4 Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 19 Apr, 2026 Reviews received at journal 18 Apr, 2026 Reviews received at journal 17 Apr, 2026 Reviewers agreed at journal 15 Apr, 2026 Reviews received at journal 13 Apr, 2026 Reviewers agreed at journal 13 Apr, 2026 Reviewers agreed at journal 12 Apr, 2026 Reviewers agreed at journal 12 Apr, 2026 Reviewers invited by journal 09 Apr, 2026 Editor assigned by journal 26 Mar, 2026 Submission checks completed at journal 26 Mar, 2026 First submitted to journal 18 Mar, 2026 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. 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4\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":37580,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003eSummary Figure: \\u003c/strong\\u003eclinical timeline\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"Summaryfig.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9163653/v1/232176804e62b5431afb3874.png\"},{\"id\":107487038,\"identity\":\"e05ec3f5-3bdb-4248-b2fa-762b25db5875\",\"added_by\":\"auto\",\"created_at\":\"2026-04-22 02:39:41\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":2027871,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9163653/v1/b0b49295-29ee-4457-8bd0-eb64643be537.pdf\"},{\"id\":107483274,\"identity\":\"581e3c0d-64ab-4b4e-a619-59637f03215f\",\"added_by\":\"auto\",\"created_at\":\"2026-04-22 02:27:07\",\"extension\":\"mp4\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":1189803,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"TEEvegetationTR.mp4\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9163653/v1/a6e3140a598de3d6ebe949fe.mp4\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Tricuspid Valve Infective Endocarditis Caused by ESBL Producing E.coli Complicated by Symptomatic AV block Requiring Temporary Epicardial Pacing: A Case Report\",\"fulltext\":[{\"header\":\"Background\",\"content\":\"\\u003cp\\u003e​​Infective endocarditis (IE) is most commonly caused by gram-positive organisms, particularly \\u003cem\\u003eStaphylococcus aureus\\u003c/em\\u003e and viridans group streptococci, while gram-negative bacteria remain an uncommon etiology. In a large prospective multinational cohort, non-HACEK gram-negative bacilli accounted for only 1.8% of all definite IE cases, underscoring the rarity of these infections in contemporary practice.[\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e] Within this already small subset, endocarditis caused by extended-spectrum β-lactamase (ESBL)\\u0026ndash;producing organisms is exceptionally rare, with only sporadic case reports described in the literature.[\\u003cspan additionalcitationids=\\\"CR3\\\" citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e] This rarity contributes to diagnostic uncertainty and a lack of standardized management strategies, particularly when complicated by atypical features such as conduction system disease.\\u003c/p\\u003e \\u003cp\\u003eESBL-producing \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e has emerged as a significant cause of bloodstream infection, especially among older adults with healthcare exposure [\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e]; however, its ability to cause native valve endocarditis remains poorly understood.[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e] Reported cases of ESBL-associated IE most commonly involve left-sided valves, particularly the mitral valve, and are frequently complicated by embolic events or require surgical intervention.[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e] Right-sided involvement, particularly isolated tricuspid valve endocarditis, is far less frequently reported, making the present case notable both for valve location and for its associated conduction abnormality.\\u003c/p\\u003e \\u003cp\\u003eInfective endocarditis involving the tricuspid valve presents unique management challenges, particularly in patients with underlying conduction system disease who are also symptomatic and require pacing. Transvenous pacemaker implantation is generally contraindicated in the setting of active endocardial infection due to the risk of persistent or recurrent infection. As a result, alternative pacing strategies must be considered, including epicardial lead placement. While epicardial pacing is well described in select surgical populations [\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e], its role in patients with right-sided infective endocarditis and brady-arrhythmias remains less commonly reported. We present a case of tricuspid valve infective endocarditis complicated by advanced conduction disease, necessitating epicardial pacemaker implantation, followed by subsequent transition to a transvenous dual-chamber system after infection resolution.\\u003c/p\\u003e\"},{\"header\":\"Case presentation\",\"content\":\"\\u003cp\\u003eA 75-year-old Caucasian male with pre-existing right bundle branch block and one year history of Whipple procedure with biliary stent placement presented four days after discharge from a recent hospitalization for sepsis due to extended-spectrum β-lactamase (ESBL) \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e bacteremia, treated with intravenous ertapenem. He reported dizziness following a syncopal episode that occurred while sitting in the passenger seat of his car. The loss of consciousness lasted approximately 30 seconds and was preceded by visual changes and mild dizziness. The patient otherwise led an active lifestyle, regularly playing golf, and had no other acute complaints.\\u003c/p\\u003e \\u003cp\\u003eOn examination, he was hemodynamically stable with normal vital signs. Cardiac evaluation revealed a regular rate and rhythm, without murmurs, rubs, or gallops. Pulmonary examination was unremarkable. Electrocardiography demonstrated sinus bradycardia with first-degree atrioventricular (AV) block and intermittent pauses, left axis deviation, and pre-existing right bundle branch block \\u003cb\\u003e(\\u003c/b\\u003eFig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e\\u003cb\\u003e).\\u003c/b\\u003e Telemetry monitoring revealed intermittent high-degree AV block.\\u003c/p\\u003e \\u003cp\\u003eLaboratory evaluation revealed normal white blood cell count and hemoglobin. Central metabolic panel notable for slight hyperkalemia (potassium of 5.3) and mildly elevated hepatic enzymes (Aspartate Aminotransferase 40, Alkaline Phosphatase 130) with preserved renal function. Blood cultures at this presentation were negative, however were positive for ESBL \\u003cem\\u003eE. coli\\u003c/em\\u003e in admission one week prior. Transthoracic echocardiogram (TTE) demonstrated normal left ventricular function without valvular abnormalities; however, the tricuspid valve was poorly visualized. Subsequent transesophageal echocardiogram (TEE) revealed a mobile mass sitting on tricuspid valve, close to septum, about 1 cm long with flagellating distal end on atrial side of the valve with no evidence of abscess formation. Mild tricuspid regurgitation was also noted \\u003cb\\u003e(\\u003c/b\\u003eFig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e\\u003cb\\u003e).\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eDifferential diagnosis for his syncope included cardiac causes (progressive AV block), dehydration, neurological etiologies, and medication-related adverse effects (ertapenem). Contributing factors for AV block included age-related degenerative disease, coronary ischemia, and metabolic derangements such as hyperkalemia or hypothyroidism. Investigations from his prior admission revealed ESBL bacteremia in both aerobic and anaerobic cultures, with sensitivity to meropenem and piperacillin-tazobactam. Infectious disease consultation at that time failed to identify a definitive source; urinalysis was normal. Bacteremia was attributed to mild cholangitis with polymicrobial bloodstream infection.\\u003c/p\\u003e \\u003cp\\u003eDue to the persistence of his symptoms, he was admitted to the cardiac care unit and started on an isoproterenol infusion. Given the contraindication of transvenous right ventricular pacemaker placement in active infective endocarditis, cardiothoracic surgery performed urgent placement of a temporary epicardial ventricular lead via mini-thoracotomy \\u003cb\\u003e(\\u003c/b\\u003eFig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ea\\u003cb\\u003e).\\u003c/b\\u003e The lead was tunneled to a left subpectoral pocket containing a dual-chamber pacemaker, with the atrial lead intentionally capped. The patient experienced improved hemodynamic and mental status post-procedure, with only mild surgical-site pain.\\u003c/p\\u003e \\u003cp\\u003eThe post-operative course was complicated by left pleural effusion and atelectasis, which was resolved with supportive management and continuation of intravenous antibiotics. The patient completed a six-week course of ertapenem and was discharged with close outpatient follow-up. One month later, repeat TEE demonstrated complete resolution of the tricuspid valve vegetation. At that time, new endocardial atrial and ventricular leads were placed, converting the system to a fully functional dual-chamber pacemaker \\u003cb\\u003e(\\u003c/b\\u003eFig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003eb\\u003cb\\u003e).\\u003c/b\\u003e\\u003c/p\\u003e\"},{\"header\":\"Discussion\",\"content\":\"\\u003cp\\u003eThough the pathogenesis of ESBL-producing \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e endocarditis is not well understood, recent studies have aimed to characterize virulence factors within phylogenetic group B2. This group has a strong association with extraintestinal pathogenic \\u003cem\\u003eE. coli\\u003c/em\\u003e (ExPEC), which are known to cause severe invasive infections.[\\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e] The most notorious member of this group, \\u003cem\\u003eE. coli\\u003c/em\\u003e clone ST131, has been identified as an emerging global threat due to its extensive repertoire of virulence and antimicrobial resistance genes.[\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e] Capsule formation, adhesion factors, and biofilm formation and maturation facilitate immune evasion and may create favorable conditions for the development of infective endocarditis.[\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e] Plasmid-associated acquired resistance genes (ARGs), such as CTX-M, as seen in our case, further limit effective antimicrobial options and may contribute to bacterial persistence. The combined presence of virulence factors and antimicrobial resistance genes presents significant challenges in clinical practice, often necessitating the use of more potent antibiotics. In this patient, the virulence and resistance profile of the organism likely contributed to persistent infection and may explain why epicardial pacing was required rather than antibiotics alone.\\u003c/p\\u003e \\u003cp\\u003eTo our knowledge, only one other case \\u0026mdash; reported by Fordyce et al \\u0026mdash; has described tricuspid valve endocarditis due to extended-spectrum β‑lactamase-producing \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e complicated by complete heart block.[\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e] While the Fordyce case and several other reports of TVIE complicated by atrioventricular conduction delay suggest resolution of block with antibiotics, conduction abnormalities in right-sided endocarditis remain exceedingly rare. In our patient, despite one week of appropriate antimicrobial therapy, there was progressive AV conduction delay with PR interval prolongation and intermittent pauses, including episodes of third-degree heart block. Because of his pre-existing AV nodal disease and the high virulence of ESBL endocarditis, the patient was at increased risk for irreversible conduction impairment, prompting urgent placement of a temporary epicardial pacemaker. This approach is consistent with evidence that baseline conduction delays such as first-degree AV block in infective endocarditis are associated with progression to high-degree AV block, reflecting more severe or invasive disease and justifying early pacing intervention.[\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e]\\u003c/p\\u003e \\u003cp\\u003eIn patients with infective endocarditis (TVIE) complicated by new or worsening atrioventricular (AV) block, surgical intervention is indicated especially if the infection is complicated by valve dysfunction, including a resistant organism, persistent infection and relapsing prosthetic valve endocarditis. [\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e] In aortic or mitral valve endocarditis, conduction disease strongly favors early surgical intervention due to the close anatomic relationship of these valves to the AV node within Koch\\u0026rsquo;s triangle, where perivalvular infection can readily disrupt the conduction system. Conversely, the tricuspid valve is more distant from the AV node, which likely explains the rarity of atrioventricular block in tricuspid valve infective endocarditis. In this setting of right sided endocarditis, the AV block may be related to inflammatory edema or transient myocardial involvement rather than structural destruction that mandates surgical repair.[\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e] Case reports support that antibiotic therapy alone can lead to resolution of AV conduction disturbances in TVIE and allows surgical intervention to be deferred. For example, Mart\\u0026iacute;nez‑Urue\\u0026ntilde;a et al. described a patient with tricuspid valve vegetations and transient trifascicular block who improved with antibiotic therapy and temporary pacing, without surgical intervention.[\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e] Similarly, Singh and Kalathiya reported reversible complete heart block in tricuspid valve endocarditis managed successfully with antibiotics, highlighting that conduction abnormalities may resolve once inflammation and bacteremia are controlled.[\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e] In our reported case, the decision was made to proceed with epicardial pacing rather than continue antibiotic therapy as the patient was severely symptomatic from the arrhythmia and had baseline AV block. Surgical intervention was reserved for antibiotic failure, unlikely event of abscess formation, vegetation enlargement, recurrent embolization, or the development of right heart failure.\\u003c/p\\u003e \\u003cp\\u003eWhile this case illustrates a rare clinical presentation of ESBL-producing E. coli endocarditis with conduction abnormalities, several limitations should be considered. Blood cultures were negative in this presentation; however, the patient had received daily intravenous ertapenem therapy for ESBL-producing E. coli bacteremia one week prior to admission, which may have contributed to culture negativity. A previous report described a similar scenario in which blood cultures were negative, but tissue cultures from a tricuspid valve replacement revealed ESBL-producing \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e as the causative pathogen. [\\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e] Another limitation in our case is the patient\\u0026rsquo;s pre-existing atrioventricular (AV) block. Although age-related degenerative conduction disease could have contributed to worsening AV conduction, it is notable that the patient developed third-degree AV block and progressive PR prolongation coinciding with the endocarditis. While we cannot definitively prove causation, the temporal relationship between the infection and conduction abnormalities supports the likelihood that the endocarditis contributed to the conduction disturbance, ultimately prompting the placement of an epicardial pacemaker.\\u003c/p\\u003e\"},{\"header\":\"Conclusion\",\"content\":\"\\u003cp\\u003eThis case illustrates an exceptionally rare presentation of native tricuspid valve infective endocarditis caused by ESBL-producing \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e, complicated by progressive high-degree atrioventricular block in a patient with pre-existing conduction disease. It emphasizes that new or worsening conduction abnormalities in the setting of bacteremia\\u0026mdash;particularly with virulent or resistant organisms\\u0026mdash;should prompt heightened suspicion for endocardial involvement, even when transthoracic imaging is nondiagnostic. Early transesophageal echocardiography was critical for diagnosis, and multidisciplinary decision-making allowed for timely hemodynamic stabilization using temporary epicardial pacing while avoiding the risks associated with transvenous systems during active infection. This case highlights the importance of individualized pacing strategies in infective endocarditis and reinforces that right-sided disease, though anatomically distant from the atrioventricular node, can still manifest with clinically significant conduction disturbances requiring urgent intervention.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003ctable border=\\\"1\\\" cellspacing=\\\"0\\\" cellpadding=\\\"0\\\" width=\\\"624\\\"\\u003e\\n \\u003ctbody\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eIE\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eInfective Endocarditis\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eTVIE\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eTricuspid Valve Infective Endocarditis\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eESBL\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eExtended-Spectrum \\u0026beta;-Lactamase\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003e\\u003cem\\u003eE. coli\\u003c/em\\u003e\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003e\\u003cem\\u003eEscherichia coli\\u003c/em\\u003e\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eAV\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eAtrioventricular\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eTTE\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eTransthoracic Echocardiography\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eTEE\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eTransesophageal Echocardiography\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eRBBB\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eRight Bundle Branch Block\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eExPEC\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eExtraintestinal Pathogenic \\u003cem\\u003eEscherichia coli\\u003c/em\\u003e\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eST131\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eSequence Type 131\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eARGs\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eAntimicrobial Resistance Genes\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003ctr\\u003e\\n \\u003ctd style=\\\"width: 127px;\\\"\\u003e\\n \\u003cp\\u003eCTX-M\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003ctd style=\\\"width: 497px;\\\"\\u003e\\n \\u003cp\\u003eCefotaximase-Munich (\\u0026beta;-lactamase enzyme family)\\u003c/p\\u003e\\n \\u003c/td\\u003e\\n \\u003c/tr\\u003e\\n \\u003c/tbody\\u003e\\n\\u003c/table\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003eEthics approval and consent to participate: Not applicable.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eConsent for publication:\\u0026nbsp;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\\n\\u003cp\\u003eAvailability of data and materials: Not applicable.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eCompeting interests: The authors declare no competing interests.\\u003c/p\\u003e\\n\\u003cp\\u003eFunding: The authors declare there is no funding support for this manuscript. Availability of data and materials Not applicable.\\u003c/p\\u003e\\n\\u003cp\\u003eAuthor contributions: R.O. contributed to the drafting and editing of the manuscript as well as the procurement and editing of images and obtaining of patient consent. S.A. contributed to the drafting and editing of the manuscript as well as the procurement and editing of images. V.T. contributed to the drafting and editing of the manuscript. V.W. contributed to the drafting and editing of the manuscript. M.J. contributed to the drafting and editing of the manuscript.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eAcknowledgements: Not applicable.\\u003c/p\\u003e\\n\\u003cp\\u003eThis research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n \\u003cli\\u003eMorpeth S, Murdoch D, Cabell CH, et al. Non-HACEK gram-negative bacillus endocarditis. \\u003cem\\u003eAnn Intern Med\\u003c/em\\u003e. 2007;147(12):829-35.\\u003c/li\\u003e\\n \\u003cli\\u003eKenzaka T, Shinkura Y, Kayama S, et al. Infective endocarditis caused by extended-spectrum \\u0026beta;-lactamase-producing Escherichia coli: a case report. \\u003cem\\u003eInfect Drug Resist\\u003c/em\\u003e. 2021;14:3357-62.\\u003c/li\\u003e\\n \\u003cli\\u003eModi HH, Modi SH, Siddiqui BR, Andreoni JM. A rare case of prosthetic valve endocarditis caused by extended-spectrum \\u0026beta;-lactamase producing Escherichia coli. \\u003cem\\u003eJ Glob Infect Dis\\u003c/em\\u003e. 2011;3(1):99-101. doi:10.4103/0974-777X.77310.\\u003c/li\\u003e\\n \\u003cli\\u003eGeorge S, Varghese J, Chandrasekhar S, et al. Gram-negative bacteria causing infective endocarditis: rare cardiac complication after liver transplantation. \\u003cem\\u003eWorld J Hepatol\\u003c/em\\u003e. 2013;5(5):296-7. doi:10.4254/wjh.v5.i5.296.\\u003c/li\\u003e\\n \\u003cli\\u003eLeistner R, Sakellariou C, G\\u0026uuml;rntke S, et al. Mortality and molecular epidemiology associated with extended-spectrum \\u0026beta;-lactamase production in Escherichia coli from bloodstream infection. \\u003cem\\u003eInfect Drug Resist\\u003c/em\\u003e. 2014;7:57-62. doi:10.2147/IDR.S56984.\\u003c/li\\u003e\\n \\u003cli\\u003eSaboe A, Sari MT, Cool CJ, et al. Cutaneous vasculitis and generalized lymphadenopathy associated with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli endocarditis: a rare case report. \\u003cem\\u003eInfect Dis Ther\\u003c/em\\u003e. 2021;10(1):583-93. doi:10.1007/s40121-020-00377-4.\\u003c/li\\u003e\\n \\u003cli\\u003eMicenkov\\u0026aacute; L, Bos\\u0026aacute;k J, Vrba M, \\u0026Scaron;evč\\u0026iacute;kov\\u0026aacute; A, \\u0026Scaron;majs D. Human extraintestinal pathogenic Escherichia coli strains differ in prevalence of virulence factors, phylogroups, and bacteriocin determinants. \\u003cem\\u003eBMC Microbiol\\u003c/em\\u003e. 2016;16:218. doi:10.1186/s12866-016-0835-z.\\u003c/li\\u003e\\n \\u003cli\\u003eLavigne JP, Vergunst A, Goret L, et al. Virulence potential and genomic mapping of the worldwide clone Escherichia coli ST131. \\u003cem\\u003ePLoS One\\u003c/em\\u003e. 2012;7(3):e34294. doi:10.1371/journal.pone.0034294.\\u003c/li\\u003e\\n \\u003cli\\u003eFl\\u0026oacute;rez-Navas PC, Josa D, Silva-Monsalve E, Ballesteros N, Casta\\u0026ntilde;eda S, Mu\\u0026ntilde;oz M, et al. Infective endocarditis caused by Escherichia coli O25b:H4-B2-ST131: a case report providing genotypic, phenotypic, and phylogenetic insights. \\u003cem\\u003eJ Int Med Res\\u003c/em\\u003e. 2025;53(12):3000605251404825. doi:10.1177/03000605251404825.\\u003c/li\\u003e\\n \\u003cli\\u003eFordyce C, Leather R, Partlow E, Swiggum E. Complete heart block associated with tricuspid valve endocarditis due to extended-spectrum \\u0026beta;-lactamase-producing Escherichia coli. \\u003cem\\u003eCan J Cardiol\\u003c/em\\u003e. 2011;27:263.e17-263.e20.\\u003c/li\\u003e\\n \\u003cli\\u003ePhilip M, Hourdain J, Resseguier N, et al. Atrioventricular conduction disorders in aortic valve infective endocarditis: occurrence, contributing factors, prognosis and evolution. \\u003cem\\u003eArch Cardiovasc Dis\\u003c/em\\u003e. 2024;117(5):304-12.\\u003c/li\\u003e\\n \\u003cli\\u003eNishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. \\u003cem\\u003eJ Am Coll Cardiol\\u003c/em\\u003e. 2014;63(22):e57-185.\\u003c/li\\u003e\\n \\u003cli\\u003eHabib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F, et al. 2015 ESC guidelines for the management of infective endocarditis. \\u003cem\\u003eEur Heart J\\u003c/em\\u003e. 2015;36(44):3075-128.\\u003c/li\\u003e\\n \\u003cli\\u003eMart\\u0026iacute;nez-Urue\\u0026ntilde;a N, Hern\\u0026aacute;ndez C, Duro I, Sand\\u0026iacute;n MG, Zatarain E, San Rom\\u0026aacute;n A. Transient trifascicular block secondary to tricuspid valve endocarditis. \\u003cem\\u003eRev Esp Cardiol (Engl Ed)\\u003c/em\\u003e. 2012;65(8):767-8.\\u003c/li\\u003e\\n \\u003cli\\u003eSingh N, Kalathiya RJ. Transient complete heart block: a case report of a rare complication of tricuspid valve infective endocarditis. \\u003cem\\u003eEur Heart J Case Rep\\u003c/em\\u003e. 2021;5(8):ytab287.\\u003c/li\\u003e\\n \\u003cli\\u003eGillham MJ, Barr TM. Temporary epicardial pacing after cardiac surgery. BJA Educ. 2023 Sep;23(9):337-349. doi: 10.1016/j.bjae.2023.05.003. Epub 2023 Jul 6. PMID: 37600212; PMCID: PMC10433321.\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"journal-of-cardiothoracic-surgery\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"jcts\",\"sideBox\":\"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)\",\"snPcode\":\"13019\",\"submissionUrl\":\"https://submission.nature.com/new-submission/13019/3\",\"title\":\"Journal of Cardiothoracic Surgery\",\"twitterHandle\":\"@BioMedCentral\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC/SO AJ\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Tricuspid Valve Infective Endocarditis, ESBL E.coli, AV block, epicardial pacing\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-9163653/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-9163653/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003e\\u003cstrong\\u003eBackground\\u003c/strong\\u003e: Infective endocarditis (IE) caused by non-HACEK gram-negative organisms is rare, accounting for fewer than 2% of cases, and endocarditis due to extended-spectrum β-lactamase (ESBL)–producing Escherichia coli is exceptionally uncommon. Right-sided involvement, particularly isolated tricuspid valve infective endocarditis (TVIE), and associated atrioventricular (AV) conduction abnormalities are rarely reported, creating diagnostic and management challenges, especially when pacing is required.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCase Presentation:\\u003c/strong\\u003e A 75-year-old Caucasian man with pre-existing right bundle branch block presented with syncope shortly after hospitalization for ESBL E. coli bacteremia treated with intravenous ertapenem. Electrocardiography revealed progressive AV conduction delay with intermittent high-degree AV block. Transthoracic echocardiography was nondiagnostic, while transesophageal echocardiography identified a tricuspid valve vegetation without abscess. Given active infective endocarditis and symptomatic conduction disease, transvenous pacing was contraindicated. The patient underwent urgent placement of a temporary epicardial ventricular lead, resulting in hemodynamic stabilization. He completed a six-week course of ertapenem with subsequent resolution of the tricuspid valve vegetation on follow-up imaging. After infection clearance, a transvenous dual-chamber pacemaker was successfully implanted.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConclusions\\u003c/strong\\u003e: This case highlights a rare presentation of ESBL-producing E. coli TVIE complicated by advanced AV block. It underscores the importance of early transesophageal imaging in suspected right-sided endocarditis, awareness of conduction disturbances as a marker of disease severity, and the role of epicardial pacing as a safe bridging strategy when permanent transvenous systems are contraindicated during active infection.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Tricuspid Valve Infective Endocarditis Caused by ESBL Producing E.coli Complicated by Symptomatic AV block Requiring Temporary Epicardial Pacing: A Case Report\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-04-19 12:14:30\",\"doi\":\"10.21203/rs.3.rs-9163653/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-04-20T03:27:31+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-04-18T21:46:50+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-04-17T13:02:04+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"192228498138472666295822875853532630883\",\"date\":\"2026-04-15T09:38:56+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-04-14T03:07:04+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"260575954289614424630772818841404396813\",\"date\":\"2026-04-14T02:53:08+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"210999374321245059255821669637999167226\",\"date\":\"2026-04-12T19:33:45+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"253503386702330581415826907422221344453\",\"date\":\"2026-04-12T07:35:25+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2026-04-09T13:31:22+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2026-03-27T00:06:44+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2026-03-27T00:05:56+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"Journal of Cardiothoracic Surgery\",\"date\":\"2026-03-19T00:28:26+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"journal-of-cardiothoracic-surgery\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"jcts\",\"sideBox\":\"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)\",\"snPcode\":\"13019\",\"submissionUrl\":\"https://submission.nature.com/new-submission/13019/3\",\"title\":\"Journal of Cardiothoracic Surgery\",\"twitterHandle\":\"@BioMedCentral\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC/SO AJ\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"3551c5da-1d5c-465c-aef9-620452c42a91\",\"owner\":[],\"postedDate\":\"April 19th, 2026\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"under-review\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-04-19T12:14:30+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2026-04-19 12:14:30\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-9163653\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-9163653\",\"identity\":\"rs-9163653\",\"version\":[\"v1\"]},\"buildId\":\"XKTyCvWXoU3ODBz1xrDgd\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}