{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T02:36:23Z","timestamp":1786502183661,"version":"build-2736575974"},"reference-count":17,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[2002,1]]},"abstract":"<jats:p>\n            <jats:bold>\n              <jats:italic>\n                <jats:bold>\n                  <jats:italic>Background<\/jats:italic>\n                  \u2014\n                <\/jats:bold>\n              <\/jats:italic>\n            <\/jats:bold>\n            Because of high pulmonary vascular resistance in patients with primary pulmonary hypertension (PPH), right atrial pressure may exceed left atrial pressure during exercise, resulting in a right-to-left shunt via a patent foramen ovale (PFO). This shunting would disturb arterial P\n            <jats:sc>co<\/jats:sc>\n            <jats:sub>2<\/jats:sub>\n            and H\n            <jats:sup>+<\/jats:sup>\n            homeostasis if the pulmonary blood were not simultaneously hyperventilated to compensate for the high CO\n            <jats:sub>2<\/jats:sub>\n            and H\n            <jats:sup>+<\/jats:sup>\n            in the shunted blood. This article first hypothesizes and then describes unique changes in gas exchange when right-to-left exercise-induced shunting (EIS) occurs.\n          <\/jats:p>\n          <jats:p>\n            <jats:bold>\n              <jats:italic>\n                <jats:bold>\n                  <jats:italic>Methods and Results<\/jats:italic>\n                  \u2014\n                <\/jats:bold>\n              <\/jats:italic>\n            <\/jats:bold>\n            Retrospectively, the cardiopulmonary exercise tests of 71 PPH patients were studied. Criteria postulated to document hyperventilation of the pulmonary blood flow due to a right-to-left EIS were (1) an abrupt and sustained increase in end-tidal O\n            <jats:sub>2<\/jats:sub>\n            with a simultaneous sustained decrease in end-tidal CO\n            <jats:sub>2<\/jats:sub>\n            ; (2) an abrupt and sustained increase in the respiratory exchange ratio; and (3) usually, an associated decline in pulse oximetry saturation. Each patient was evaluated for a PFO with resting echocardiography. The investigators interpreting the gas exchange evidence of EIS were blinded to the echocardiographic readings. Forty-five percent of the patients had demonstrable EIS by gas exchange criteria. Almost all were also positive for a PFO by echocardiography. Using the resting echocardiograph as the reference, the sensitivity, specificity, positive and negative predictive values, and accuracy were all between 90% to 96%.\n          <\/jats:p>\n          <jats:p>\n            <jats:bold>\n              <jats:italic>\n                <jats:bold>\n                  <jats:italic>Conclusions<\/jats:italic>\n                  \u2014\n                <\/jats:bold>\n              <\/jats:italic>\n            <\/jats:bold>\n            Exercise-induced right-to-left shunting can be detected by noninvasive, cardiopulmonary exercise testing in patients with PPH.\n          <\/jats:p>","DOI":"10.1161\/hc0102.101509","type":"journal-article","created":{"date-parts":[[2002,7,28]],"date-time":"2002-07-28T23:16:47Z","timestamp":1027898207000},"page":"54-60","update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":150,"title":["Gas Exchange Detection of Exercise-Induced Right-to-Left Shunt in Patients With Primary Pulmonary Hypertension"],"prefix":"10.1161","volume":"105","author":[{"given":"Xing-Guo","family":"Sun","sequence":"first","affiliation":[{"name":"From the Department of Medicine, Harbor-UCLA Medical Center, Torrance, Calif."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James E.","family":"Hansen","sequence":"additional","affiliation":[{"name":"From the Department of Medicine, Harbor-UCLA Medical Center, Torrance, Calif."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronald J.","family":"Oudiz","sequence":"additional","affiliation":[{"name":"From the Department of Medicine, Harbor-UCLA Medical Center, Torrance, Calif."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karlman","family":"Wasserman","sequence":"additional","affiliation":[{"name":"From the Department of Medicine, Harbor-UCLA Medical Center, Torrance, Calif."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"e_1_3_1_1_2","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1988.64.1.234"},{"key":"e_1_3_1_2_2","doi-asserted-by":"publisher","DOI":"10.1161\/circ.104.4.429"},{"key":"e_1_3_1_3_2","unstructured":"Wasserman K Hansen JE Sue DY et al. Principles of Exercise Testing and Interpretation. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 1999."},{"key":"e_1_3_1_4_2","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1973.34.1.128"},{"key":"e_1_3_1_5_2","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1980.49.3.456"},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1161\/circ.73.6.3698248"},{"key":"e_1_3_1_7_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0002-9149(84)91617-5"},{"key":"e_1_3_1_8_2","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM198805053181802"},{"key":"e_1_3_1_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9149(92)91228-V"},{"key":"e_1_3_1_10_2","doi-asserted-by":"publisher","DOI":"10.1161\/str.29.7.1322"},{"key":"e_1_3_1_11_2","doi-asserted-by":"publisher","DOI":"10.1007\/s004210050354"},{"key":"e_1_3_1_12_2","doi-asserted-by":"publisher","DOI":"10.1161\/circ.101.24.2803"},{"key":"e_1_3_1_13_2","unstructured":"Glantz SA. Primer of Biostatistics. 4th ed. San Francisco: McGraw-Hill; 1997."},{"key":"e_1_3_1_14_2","unstructured":"Portney LG Watkins MP. Foundations of Clinical Research: Applications to Practice. 2nd ed. Upper Saddle River: Prentice-Hall; 2000."},{"key":"e_1_3_1_15_2","first-page":"824","volume":"119","year":"2000","unstructured":"Ting H, Sun XG, Chuang ML, et al. A noninvasive assessment of pulmonary perfusion abnormality in patients with primary pulmonary hypertension. Chest. 2000; 119: 824\u2013832.","journal-title":"Chest"},{"key":"e_1_3_1_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0025-6196(12)60336-X"},{"key":"e_1_3_1_17_2","doi-asserted-by":"publisher","DOI":"10.1183\/09031936.01.17406470"}],"container-title":["Circulation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ahajournals.org\/doi\/full\/10.1161\/hc0102.101509","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,14]],"date-time":"2024-05-14T01:46:19Z","timestamp":1715651179000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/hc0102.101509"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2002,1]]},"references-count":17,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2002,1]]}},"alternative-id":["10.1161\/hc0102.101509"],"URL":"https:\/\/doi.org\/10.1161\/hc0102.101509","relation":{},"ISSN":["0009-7322","1524-4539"],"issn-type":[{"value":"0009-7322","type":"print"},{"value":"1524-4539","type":"electronic"}],"subject":[],"published":{"date-parts":[[2002,1]]},"assertion":[{"value":"2002-01-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}