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

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 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.