Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation?
Background Patients with a Fontan circulation achieve lower peak heart rates (HR) 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 HR acceleration thro...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2019-05-01
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| Series: | Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease |
| Subjects: | |
| Online Access: | https://www.ahajournals.org/doi/10.1161/JAHA.119.012008 |
| _version_ | 1818776765161537536 |
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| author | Guido Claessen Andre La Gerche Alexander Van De Bruaene Mathias Claeys Rik Willems Steven Dymarkowski Jan Bogaert Piet Claus Werner Budts Hein Heidbuchel Marc Gewillig |
| author_facet | Guido Claessen Andre La Gerche Alexander Van De Bruaene Mathias Claeys Rik Willems Steven Dymarkowski Jan Bogaert Piet Claus Werner Budts Hein Heidbuchel Marc Gewillig |
| author_sort | Guido Claessen |
| collection | DOAJ |
| description | Background Patients with a Fontan circulation achieve lower peak heart rates (HR) 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 HR acceleration throughout exercise relative to metabolic demand and cardiac output in patients with a Fontan circulation relative to healthy controls. Methods and Results 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 HR reserve was assessed by determining the exercise‐induced increase (∆) in cardiac index, stroke volume, and HR relative to the increase in oxygen consumption (VO2). HR reserve was lower in Fontan patients compared with controls (71±21 versus 92±15 bpm; P=0.001). In contrast, increases in HR relative to workload and VO2 were higher than in controls. The change in cardiac index relative to the change in VO2 (∆cardiac index/∆VO2) was similar between groups, but Fontan patients had increased ∆HR/∆VO2 and reduced ∆ stroke volume/∆VO2 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 HR. Conclusions 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 HR would be physiologically implausible. Thus, abnormal cardiac filling rather than sinoatrial node dysfunction explains the diminished HR reserve in Fontan patients. |
| first_indexed | 2024-12-18T11:18:08Z |
| format | Article |
| id | doaj.art-ae31a8ed9fa24946b60b65b10efb2c52 |
| institution | Directory Open Access Journal |
| issn | 2047-9980 |
| language | English |
| last_indexed | 2024-12-18T11:18:08Z |
| publishDate | 2019-05-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease |
| spelling | doaj.art-ae31a8ed9fa24946b60b65b10efb2c522022-12-21T21:09:52ZengWileyJournal of the American Heart Association: Cardiovascular and Cerebrovascular Disease2047-99802019-05-018910.1161/JAHA.119.012008Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation?Guido Claessen0Andre La Gerche1Alexander Van De Bruaene2Mathias Claeys3Rik Willems4Steven Dymarkowski5Jan Bogaert6Piet Claus7Werner Budts8Hein Heidbuchel9Marc Gewillig10Department of Cardiovascular Sciences KU Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumUniversity Hospitals Leuven Leuven BelgiumUniversity Hospitals Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumUniversity Hospital Antwerp Antwerp BelgiumDepartment of Cardiovascular Sciences KU Leuven Leuven BelgiumBackground Patients with a Fontan circulation achieve lower peak heart rates (HR) 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 HR acceleration throughout exercise relative to metabolic demand and cardiac output in patients with a Fontan circulation relative to healthy controls. Methods and Results 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 HR reserve was assessed by determining the exercise‐induced increase (∆) in cardiac index, stroke volume, and HR relative to the increase in oxygen consumption (VO2). HR reserve was lower in Fontan patients compared with controls (71±21 versus 92±15 bpm; P=0.001). In contrast, increases in HR relative to workload and VO2 were higher than in controls. The change in cardiac index relative to the change in VO2 (∆cardiac index/∆VO2) was similar between groups, but Fontan patients had increased ∆HR/∆VO2 and reduced ∆ stroke volume/∆VO2 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 HR. Conclusions 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 HR would be physiologically implausible. Thus, abnormal cardiac filling rather than sinoatrial node dysfunction explains the diminished HR reserve in Fontan patients.https://www.ahajournals.org/doi/10.1161/JAHA.119.012008cardiac magnetic resonance imagingchronotropic incompetenceexercise physiologyFontan procedureheart rate |
| spellingShingle | Guido Claessen Andre La Gerche Alexander Van De Bruaene Mathias Claeys Rik Willems Steven Dymarkowski Jan Bogaert Piet Claus Werner Budts Hein Heidbuchel Marc Gewillig Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease cardiac magnetic resonance imaging chronotropic incompetence exercise physiology Fontan procedure heart rate |
| title | Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? |
| title_full | Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? |
| title_fullStr | Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? |
| title_full_unstemmed | Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? |
| title_short | Heart Rate Reserve in Fontan Patients: Chronotropic Incompetence or Hemodynamic Limitation? |
| title_sort | heart rate reserve in fontan patients chronotropic incompetence or hemodynamic limitation |
| topic | cardiac magnetic resonance imaging chronotropic incompetence exercise physiology Fontan procedure heart rate |
| url | https://www.ahajournals.org/doi/10.1161/JAHA.119.012008 |
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