{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T22:26:04Z","timestamp":1790375164718,"version":"4.1.0"},"reference-count":5,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Cardiovasc electrophysiol"],"published-print":{"date-parts":[[2026,9]]},"abstract":"ABSTRACT<\/jats:title>\n \n Introduction<\/jats:title>\n Elevated shock impedance during extravascular implantable cardioverter\u2010defibrillator (EV\u2010ICD) implantation may preclude defibrillation threshold (DFT) testing despite appropriate retrosternal lead position. We describe suspected mediastinal air entrapment as a reversible mechanism and a simple preventive strategy.<\/jats:p>\n <\/jats:sec>\n \n Methods and Results<\/jats:title>\n \n During early EV\u2010ICD implantation experience, two patients developed shock impedance >\u2009200 \u03a9 immediately after retrosternal lead placement, with associated sensing abnormalities. Lead repositioning did not normalize impedance, no pneumothorax was identified, and DFT testing was deferred. Shock impedance normalized spontaneously within 1\u20132 days, permitting successful DFT testing without lead revision. Transient mediastinal air entrapment along the defibrillation vector was suspected. A procedural modification was adopted in which 5\u201310\u2009cm H\n 2<\/jats:sub>\n O positive end\u2010expiratory pressure was applied immediately before retrosternal introducer removal, followed by prompt EV\u2010ICD lead advancement. Among five consecutive subsequent implantations using this approach, initial shock impedance remained within the expected range, permitting immediate DFT testing without lead repositioning or delay.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n Transient mediastinal air entrapment may cause elevated shock impedance during EV\u2010ICD implantation. Positive end\u2010expiratory pressure during introducer removal may mitigate this complication and facilitate reliable intraoperative DFT testing.<\/jats:p>\n <\/jats:sec>","DOI":"10.1111\/jce.70426","type":"journal-article","created":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T19:48:54Z","timestamp":1782848934000},"page":"2116-2118","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Mediastinal Air Entrapment During Extravascular ICD Implantation: A Preventable Cause of Elevated Shock Impedance"],"prefix":"10.1111","volume":"37","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6020-082X","authenticated-orcid":false,"given":"Robert N.","family":"Kerley","sequence":"first","affiliation":[{"name":"Cardiac Arrhythmia Service Brigham and Women's Hospital Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7965-0297","authenticated-orcid":false,"given":"Sunil","family":"Kapur","sequence":"additional","affiliation":[{"name":"Cardiac Arrhythmia Service Brigham and Women's Hospital Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,6,30]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1111\/jce.15511"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1111\/jce.15190"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.hrthm.2025.09.038"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1093\/europace\/euac046"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1097\/00000542-200701000-00026"}],"container-title":["Journal of Cardiovascular Electrophysiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/jce.70426","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/jce.70426","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/jce.70426","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T13:39:02Z","timestamp":1789479542000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/jce.70426"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,30]]},"references-count":5,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2026,9]]}},"alternative-id":["10.1111\/jce.70426"],"URL":"https:\/\/doi.org\/10.1111\/jce.70426","archive":["Portico"],"relation":{},"ISSN":["1045-3873","1540-8167"],"issn-type":[{"value":"1045-3873","type":"print"},{"value":"1540-8167","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,30]]},"assertion":[{"value":"2026-03-08","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-06-18","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-06-30","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}