Objectives
To evaluate the relationship between myocardial fibrosis identified by cardiac magnetic resonance (CMR) and ventricular performance and arrhythmias in patients late after the Fontan operation.
Background
Patients who have undergone the Fontan palliation may develop ventricular dysfunction and arrhythmias, but the mechanisms and risk factors are poorly defined.
Methods
All patients who have had a Fontan operation and a CMR study with the myocardial delayed enhancement technique from January 2002 to November 2008 were retrospectively identified.
Results
Of 90 patients (mean age at study 23.1 ± 10.9 years), 25 (28%) had positive late gadolinium enhancement (LGE) in the ventricular myocardium. Patients with positive LGE had lower mean ejection fraction (EF) (45% v. 56%, P<0.001), increased median end-diastolic volume (EDVi) (100 mL/BSA1.3 v. 82 mL/BSA1.3, P=0.004), increased median ventricular massi (63 g/BSA1.3 v. 45 g/BSA1.3, P<0.001), higher frequency of regional wall motion abnormalities (52% v. 28%, P=0.05), and higher frequency of non-sustained ventricular tachycardia (NSVT) (36% v. 11%, P=0.01). Multivariate regression analysis demonstrated that more extensive positive LGE, expressed as percent LGE of total myocardial mass, was associated with lower EF (P=0.002), increased EDVi (P<0.001), increased massi (P<0.001), and a higher frequency of NSVT (OR 1.2, 95% CI 1.1 to 1.4, P=0.006).
Conclusions
In this cohort of late Fontan survivors, myocardial fibrosis was common and associated with adverse ventricular mechanics and higher prevalence of NSVT. Further studies are warranted to examine the utility of LGE for risk stratification and treatment of ventricular arrhythmia and dysfunction in Fontan patients.