Abstract 19350: Ventricular Functional Response During Exercise in Patients After Fontan
Background: Patients with a functionally univentricular heart after Fontan are at risk for long-term complications. The influence of ventricular systolic and diastolic function and functional reserve on exercise performance has not been well established in this population. The aim of the current study was to assess ventricular systolic and diastolic response during exercise in children after Fontan completion using semi-supine cycle ergometry stress echocardiography (SSCE).
Materials and Methods: Sixteen Fontan patients (11 RV dominant, 5 LV dominant), mean age 14.2±2.1y and 16 age and gender matched controls were included. A stepwise SSCE protocol was used. TDI peak systolic (s’), early diastolic (e’) velocities and myocardial acceleration during isovolumic contraction (IVA) were measured in the free wall of the dominant ventricle at rest and at incremental heart rates (HR) and compared to control results at the LV lateral wall. IVA was used to evaluate the force-frequency relationship (FFR).
Results: Systolic function was qualitatively good in all patients and there was no more than mild valvar regurgitation. Resting HR was not significantly different between patients and controls but peak HR was lower in the Fontan group vs controls (p=0.003). Systolic and diastolic TDI velocities, but not IVA values, were lower at rest in Fontan patients (s’ 3.5±1.2 vs. 7.5±2.5 cm/sec; e’ 5.9±1.9 vs. 12.9±3.0 cm/sec, p<0.001). At peak exercise all parameters were lower in the Fontan group (s’ 6.4±1.3 vs. 14.4±4 cm/sec; e’ 9.4±2.8 vs. 18.2±3.7 cm/sec, p<0.001; IVA 2.9±1.1 vs. 5.6±1.6 m/sec2, p=0.001). During increasing HR, TDI velocities and FFR showed a blunted response in Fontan patients compared to controls (see figure).
Conclusions: Our results suggest significantly reduced systolic and diastolic myocardial response to exercise in Fontan patients compared to normal controls. The mechanism and clinical implications of these findings require further investigation.
Author Disclosures: B. Cifra: None. L. Mertens: None. C. Slorach: None. M.K. Friedberg: None. A. Dragulescu: None.
- © 2014 by American Heart Association, Inc.