Abstract 2338: Effects of Regional Dysfunction on Global Right Ventricular Systolic Function and Clinical Status in Patients with Repaired Tetralogy of Fallot
Background: In patients with repaired tetralogy of Fallot (TOF), depressed global right ventricular (RV) systolic function is associated with impaired clinical status. Underlying mechanisms contributing to global RV dysfunction in these patients are incompletely understood. We therefore sought to quantitatively analyze regional RV abnormalities and to determine the relationship between these and global RV function and clinical status.
Methods and Results: Clinical and cardiac magnetic resonance (CMR) data from 62 consecutive patients with repaired TOF were analyzed. Median age at TOF repair was 1.2 years (range 9 days - 46 years). Median age at last follow-up was 30 years (range 7 years–67 years). Using CMR data of RV volumes, 3-dimensional RV endocardial surface models were reconstructed through the application of a novel triangulation algorithm and the correspondence between end-diastole and end-systole was computed. Regional RV abnormalities were quantified and expressed as segmental ejection fraction (EF), dyskinetic area, displacement of dyskinetic area and score of extent of late gadolinium enhancement (LGE). Regional abnormalities of function and hyperenhancement were greatest in the right ventricular outflow tract (RVOT). Global RV EF correlated with regional RVOT abnormalities as follows: RVOT EF r=0.58, p<0.0001; RVOT dyskinetic area r=−0.48, p<0.0001; RVOT displacement of dyskinetic area r=−0.42, p< 0.0001 and RVOT LGE score r=−0.35, p=0.006. Aerobic capacity measured on exercise testing correlated with global RV EF (r= 0.43, p= 0.009) and RVOT EF (r= 0.42, p= 0.01). Sustained ventricular tachycardia (VT) was associated with decreased RVOT EF (p= 0.05) but not with global RVEF. Higher LGE score in the RVOT was associated with symptomatic heart failure and/or VT (p= 0.036).
Conclusion: Greater extent of regional wall motion abnormality and LGE in the RVOT adversely affect global RV function and clinical status after TOF repair. These regional measures may have important implications for risk stratification and surgical management, including RVOT reconstruction, at the time of pulmonary valve replacement.