Abstract 18538: Subclinical Left Ventricular Dysfunction, Adverse Myocardial and Aortic Remodeling in Patients With Tetralogy of Fallot Late After Surgical Repair

Abstract

Introduction: In patients after repair of tetralogy of Fallot (ToF) there is increasing evidence that left ventricular dysfunction and dilation may be present even in younger patients, which could potentially accelerate the occurrence of left heart failure. We examined by cardiac magnetic resonance (CMR) imaging if impaired LV function, diffuse myocardial fibrosis, and increased aortic stiffness is prevalent in asymptomatic ToF. Methods: CMR at 3T was performed in 109 asymptomatic ToF patients (age, 19.3±12.8 years) after surgical correction (16.6±10.0 years post operation) and 64 age-matched controls. Parameters of aortic distensibility (at 4 different aortic locations) and ventricular volumes were obtained from cine CMR. In a subset (n=50), myocardial extracellular volume fraction (ECV) was calculated from pre- and post-gadolinium contrast T1 measurements of blood and myocardium accounting for hematocrit. Results: Compared to control subjects, ToF patients had increased indexed LV endsystolic volumes resulting in a lower ejection fraction (LVEF; 50.7 ± 8.8 versus 59.0 ± 5.4; p<0.01). The RV enddiastolic and endsystolic volumes were also increased (p<0.01). Patients with TOF had a higher LV mass-to-volume ratio and increased aortic distensibility, reflecting alterations in ventricular-vascular coupling. Left atrial passive and total ejection fraction were decreased, and were associated with age (p<0.01) suggesting early onset of diastolic dysfunction. ECV was elevated in patients with ToF (0.32 ± 0.05 versus 0.26 ± 0.01 in controls (p<0.01), more so in females (p<0.05), and was inversely associated with indexed LV mass (p<0.05). Conclusion: Asymptomatic repaired ToF patients have subclinical alterations in LV geometry, function, aortic distensibility, and tissue architecture (by ECV). These findings indicate an early adverse cardiovascular phenotype that may reinforce a long-term risk burden of incipient LV failure in addition to effects on the RV.