{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T17:18:45Z","timestamp":1788542325419,"version":"build-2803163510"},"reference-count":24,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"9","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["JAHA"],"published-print":{"date-parts":[[2019,5,7]]},"abstract":"<jats:sec xml:lang=\"en\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p xml:lang=\"en\">\n                      Patients with a Fontan circulation achieve lower peak heart rates (\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      ) during exercise. Whether this impaired chronotropic response reflects pathology of the sinoatrial node or is a consequence of altered cardiac hemodynamics is uncertain. We evaluated the adequacy of\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      acceleration throughout exercise relative to metabolic demand and cardiac output in patients with a Fontan circulation relative to healthy controls.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec xml:lang=\"en\">\n                    <jats:title>Methods and Results<\/jats:title>\n                    <jats:p xml:lang=\"en\">\n                      Thirty subjects (20 healthy controls and 10 Fontan patients) underwent cardiac magnetic resonance imaging with simultaneous invasive pressure recording via a pulmonary and radial artery catheter during supine bicycle exercise to near maximal exertion. Adequacy of cardiac index, stroke volume, and\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      reserve was assessed by determining the exercise\u2010induced increase (\u2206) in cardiac index, stroke volume, and\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      relative to the increase in oxygen consumption (\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      ).\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      reserve was lower in Fontan patients compared with controls (71\u00b121 versus 92\u00b115\u00a0bpm;\n                      <jats:italic>P<\/jats:italic>\n                      =0.001). In contrast, increases in\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      relative to workload and\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      were higher than in controls. The change in cardiac index relative to the change in\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      (\u2206cardiac index\/\u2206\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      ) was similar between groups, but Fontan patients had increased \u2206\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      \/\u2206\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      and reduced \u2206 stroke volume\/\u2206\n                      <jats:styled-content style=\"fixed-case\">VO<\/jats:styled-content>\n                      <jats:sub>2<\/jats:sub>\n                      compared with controls. There was an early and marked reduction in stroke volume during exercise in Fontan patients corresponding with a plateau in cardiac output at a low peak\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      .\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec xml:lang=\"en\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p xml:lang=\"en\">\n                      In Fontan patients, the chronotropic response is appropriate relative to exercise intensity, implying normal sinoatrial function. However, premature reductions in ventricular filling and stroke volume cause an early plateau in cardiac output beyond which further increases in\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      would be physiologically implausible. Thus, abnormal cardiac filling rather than sinoatrial node dysfunction explains the diminished\n                      <jats:styled-content style=\"fixed-case\">HR<\/jats:styled-content>\n                      reserve in Fontan patients.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1161\/jaha.119.012008","type":"journal-article","created":{"date-parts":[[2019,5,1]],"date-time":"2019-05-01T05:16:26Z","timestamp":1556687786000},"update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":85,"title":["Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation?"],"prefix":"10.1161","volume":"8","author":[{"given":"Guido","family":"Claessen","sequence":"first","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"},{"name":"Baker IDI Heart and Diabetes Institute Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andre","family":"La Gerche","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"Baker IDI Heart and Diabetes Institute Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander","family":"Van De Bruaene","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathias","family":"Claeys","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rik","family":"Willems","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven","family":"Dymarkowski","sequence":"additional","affiliation":[{"name":"University Hospitals Leuven Leuven Belgium"},{"name":"Department of Imaging &amp; Pathology KU Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan","family":"Bogaert","sequence":"additional","affiliation":[{"name":"University Hospitals Leuven Leuven Belgium"},{"name":"Department of Imaging &amp; Pathology KU Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Piet","family":"Claus","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Werner","family":"Budts","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hein","family":"Heidbuchel","sequence":"additional","affiliation":[{"name":"University Hospital Antwerp Antwerp Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marc","family":"Gewillig","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Sciences KU Leuven Leuven Belgium"},{"name":"University Hospitals Leuven Leuven Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jacc.2006.05.051"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijcard.2008.01.032"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1136\/heartjnl-2015-307467"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCULATIONAHA.110.940577"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jchf.2015.05.010"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCIMAGING.113.001243"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCIMAGING.112.980037"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0733-8651(18)30211-X"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1136\/hrt.40.8.923"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9343(77)90829-4"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1915.sp001736"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1016\/0002-8703(88)90887-3"},{"key":"e_1_3_2_14_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1540-8159.1993.tb01712.x"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1540-8159.1991.tb02815.x"},{"key":"e_1_3_2_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jacc.2006.03.022"},{"key":"e_1_3_2_17_2","doi-asserted-by":"publisher","DOI":"10.1161\/circ.102.suppl_3.III-154"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1161\/JAHA.118.009185"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1093\/eurheartj\/ehy566.6014"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jacc.2017.03.582"},{"key":"e_1_3_2_21_2","doi-asserted-by":"publisher","DOI":"10.1249\/01.mss.0000174886.08219.85"},{"key":"e_1_3_2_22_2","doi-asserted-by":"publisher","DOI":"10.1088\/0967-3334\/36\/5\/N85"},{"key":"e_1_3_2_23_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1748-1716.1960.tb01953.x"},{"key":"e_1_3_2_24_2","doi-asserted-by":"publisher","DOI":"10.1161\/01.CIR.62.3.528"},{"key":"e_1_3_2_25_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0167-5273(02)00530-2"}],"container-title":["Journal of the American Heart Association"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ahajournals.org\/doi\/full\/10.1161\/JAHA.119.012008","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,13]],"date-time":"2024-05-13T07:37:18Z","timestamp":1715585838000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/JAHA.119.012008"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,5,7]]},"references-count":24,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2019,5,7]]}},"alternative-id":["10.1161\/JAHA.119.012008"],"URL":"https:\/\/doi.org\/10.1161\/jaha.119.012008","relation":{},"ISSN":["2047-9980"],"issn-type":[{"value":"2047-9980","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,5,7]]},"assertion":[{"value":"2019-01-30","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2019-04-05","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2019-05-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e012008"}}