{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,31]],"date-time":"2025-12-31T04:36:27Z","timestamp":1767155787431,"version":"build-2238731810"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2003,2,1]]},"abstract":"<jats:p>We determined whether early changes in central haemodynamics, as determined by transthoracic impedance, induced by a 70\u00b0 head-up tilt (HUT) test could predict syncope. Heart rate, arterial blood pressure and central haemodynamics [pre-ejection period and rapid left ventricular ejection time (T1), slow ejection time (T2) and dZ\/dtmax (where Z is thoracic impedance), assessed by the transthoracic impedance technique], were recorded during supine rest and during a 45min 70\u00b0 HUT test in 68 patients (40\u00b12 years) with a history of unexplained recurrent syncope. We found that 38 patients (42\u00b13 years) had a symptomatic outcome to 70\u00b0 HUT (fainters) and 30 (39\u00b12 years) had a negative outcome (non-fainters). When measured between 5 and 10min of 70\u00b0 HUT, T2 had increased significantly only in the fainters, and a change in T2 of &amp;gt;40ms from baseline predicted a positive outcome with a sensitivity of 68% and a specificity of 70%. During supine rest prior to 70\u00b0 HUT, the fainters exhibited a shorter T2 than non-fainters (183\u00b110 compared with 233\u00b114ms; P&amp;lt;0.01), and a T2 of &amp;lt;199ms predicted a positive outcome to 70\u00b0 HUT with a sensitivity of 68% and a specificity of 63%. Incorporation of the changes that occurred from rest to 70\u00b0 HUT in other haemodynamic variables (heart rate &amp;gt;11 beats\/min, systolic pressure &amp;lt;2 mmHg, diastolic pressure &amp;lt;7 mmHg and pulse pressure &amp;lt;-3 mmHg) increased the specificity to 97% and the positive predictive value to 93%. Thus transthoracic impedance could detect differences in central haemodynamics between fainters and non-fainters during supine rest and during the initial period of 70\u00b0 HUT with a consistent sensitivity and specificity when combined with peripheral haemodynamic variables.<\/jats:p>","DOI":"10.1042\/cs1040119","type":"journal-article","created":{"date-parts":[[2015,8,7]],"date-time":"2015-08-07T07:44:09Z","timestamp":1438933449000},"page":"119-126","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Changes in the transthoracic impedance signal predict the outcome of a 70\u00b0 head-up tilt test"],"prefix":"10.1042","volume":"104","author":[{"given":"Elisabeth","family":"BELLARD","sequence":"first","affiliation":[{"name":"Laboratoire de Physiologie - UPRES EA 2170, Facult\u00e9 de M\u00e9decine, rue haute de Recul\u00e9e, 49035 Angers cedex, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacques-Olivier","family":"FORTRAT","sequence":"additional","affiliation":[{"name":"Laboratoire de Physiologie - UPRES EA 2170, Facult\u00e9 de M\u00e9decine, rue haute de Recul\u00e9e, 49035 Angers cedex, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"SCHANG","sequence":"additional","affiliation":[{"name":"Ecole Sup\u00e9rieure d'Electronique de l'Ouest, 4 rue Merlet de la Boulaye, P.O. Box 926, 49009 Angers cedex 01, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jean-Marc","family":"DUPUIS","sequence":"additional","affiliation":[{"name":"D\u00e9partement de Cardiologie, Centre Hospitalier d'Angers, rue Larrey, 49033 Angers cedex, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacques","family":"VICTOR","sequence":"additional","affiliation":[{"name":"D\u00e9partement de Cardiologie, Centre Hospitalier d'Angers, rue Larrey, 49033 Angers cedex, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Georges","family":"LEFTH\u00c9RIOTIS","sequence":"additional","affiliation":[{"name":"Laboratoire de Physiologie - UPRES EA 2170, Facult\u00e9 de M\u00e9decine, rue haute de Recul\u00e9e, 49035 Angers cedex, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","published-online":{"date-parts":[[2003,1,14]]},"container-title":["Clinical Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/clinsci\/article-pdf\/104\/2\/119\/433649\/cs1040119.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/clinsci\/article-pdf\/104\/2\/119\/433649\/cs1040119.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,5,14]],"date-time":"2023-05-14T20:11:21Z","timestamp":1684095081000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/clinsci\/article\/104\/2\/119\/67319\/Changes-in-the-transthoracic-impedance-signal"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003,1,14]]},"references-count":0,"aliases":["10.1042\/cs20020169"],"journal-issue":{"issue":"2","published-print":{"date-parts":[[2003,2,1]]}},"URL":"https:\/\/doi.org\/10.1042\/cs1040119","relation":{},"ISSN":["0143-5221","1470-8736"],"issn-type":[{"value":"0143-5221","type":"print"},{"value":"1470-8736","type":"electronic"}],"subject":[],"published":{"date-parts":[[2003,1,14]]}}}