Haemodynamics in children with a Fontan circulation: effects of afterload reduction

Doctoral Thesis

The Fontan procedure is currently the palliative solution for children born with a univentricular heart. Despite an improved survival rate, many patients still suffer from complications, such as heart failure. For this reason, both patients with and without heart failure are often treated with angiotensin-converting enzyme (ACE) inhibitors, although the effectiveness is unclear. In this thesis, we investigated various aspects of the Fontan circulation to assess not only the efficacy and side effects of ACE inhibition, but also the limitations of exercise capacity and the response of the circulation of these patients to acute volume loading tests. We showed that short-term ACE inhibition had no positive effects on exercise capacity, haemodynamics and cardiac function. It also appeared to have no negative effect on the Fontan circulation, apart from side effects during the titration period. Furthermore, we found that even relatively healthy young Fontan patients have reduced...Show moreThe Fontan procedure is currently the palliative solution for children born with a univentricular heart. Despite an improved survival rate, many patients still suffer from complications, such as heart failure. For this reason, both patients with and without heart failure are often treated with angiotensin-converting enzyme (ACE) inhibitors, although the effectiveness is unclear. In this thesis, we investigated various aspects of the Fontan circulation to assess not only the efficacy and side effects of ACE inhibition, but also the limitations of exercise capacity and the response of the circulation of these patients to acute volume loading tests. We showed that short-term ACE inhibition had no positive effects on exercise capacity, haemodynamics and cardiac function. It also appeared to have no negative effect on the Fontan circulation, apart from side effects during the titration period. Furthermore, we found that even relatively healthy young Fontan patients have reduced exercise capacity associated with diastolic dysfunction and aortic stiffness. Nevertheless, we found that paediatric Fontan patients are able to respond adequately to acute volume changes and they seem to adapt well to the Fontan circulation.
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Fontan circulation

Single ventricle

Cardiac autonomic nervous activity