Right Ventricular Failure After Tetralogy of Fallot Repair
What is the rate of ventricular dilation and dysfunction in patients with repaired tetralogy of Fallot (TOF)?
This study compared changes in ventricular size and function in 339 patients with serial cardiac magnetic resonance (CMR) imaging from a multicenter TOF registry. Patients with significant disease progression (increase in right ventricular [RV] end-diastolic volume index ≥30 ml/m2, decrease in RV ejection fraction ≥10%, or decrease in left ventricular ejection fraction ≥10%) were compared with those with no progression (increase in RV end-diastolic volume index ≤5 ml/m2, RV ejection fraction decrease ≤3%, and left ventricular ejection fraction decrease ≤3%).
A total of 849 serial CMR studies from the 339 patients were examined (median interval 2.2 years for 507 CMR pairs). Significant disease progression was observed in 15% (n = 76/507) of patients, with no progression seen in 26% (n = 133/507). The remainder of patients experienced slow disease progression. Mean changes during this follow-up period of 2.2 years included increased RV end-diastolic volume index (4 ± 18 ml/m2, p < 0.001), decreased RV ejection fraction (1 ± 6%, p = 0.02), and decreased left ventricular ejection fraction (1 ± 6%, p = 0.001). There were no significant differences between groups with significant versus no progression in regards to demographic, anatomic, surgical, electrocardiographic, or baseline exercise findings. The optimal time to identify disease progression on CMR was 3 years using receiver operator curve analysis.
Rates of ventricular dysfunction and dilation are variable in patients with TOF repair. There are no clear predictors of which patients are more likely to experience adverse ventricular changes.
This study characterizes the natural history of left and right ventricular dysfunction and dilation in patients with TOF repair. While a large majority of patients experienced slow adverse ventricular changes, no progression was seen in 26%, and rapid progression was observed in 15%. Unfortunately, none of the examined variables were associated with differences in the rate of adverse ventricular changes, suggesting that serial imaging may be required to identify those patients with rapid ventricular dilation and/or dysfunction. This study supports existing proposals that recommend serial CMR every 3 years.
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