Myocardial fibrosis identified by cardiac magnetic resonance late gadolinium enhancement is associated with adverse ventricular mechanics and ventricular tachycardia late after Fontan operation

Abstract

Objectives: The purpose of this study was 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 was 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 (45% vs. 56%; p < 0.001), increased median end-diastolic volume (100 ml/body surface area [BSA](1.3) vs. 82 ml/BSA(1.3); p = 0.004), increased median ventricular mass(i) (63 g/BSA(1.3) vs. 45 g/BSA(1.3); p < 0.001), higher frequency of regional wall motion abnormalities (52% vs. 28%; p = 0.05), and higher frequency of nonsustained ventricular tachycardia (NSVT) (36% vs. 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 ejection fraction (p = 0.002), increased end-diastolic volume (p < 0.001), increased mass(i) (p < 0.001), and a higher frequency of NSVT (odds ratio 1.2; 95% confidence interval: 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 a 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.

Figure 1

Locations and Patterns of LGE Late After Fontan Operation (A) The arrow points to a transmural late gadolinium enhancement (LGE) lesion involving the ventricular septum. (B) The arrowhead points to a primary subendocardial lesion with transmural extension in the free wall of the primary ventricle, whereas the full arrow identifies endocardial fibroelastosis. (C) The arrow points to a subepicardial LGE lesion in the free wall of the primary ventricle. (D) Speckled pattern (arrows) in the free wall of the primary ventricle. LV = left ventricle; RV = right ventricle.