Determinants of Left Ventricular Dysfunction and Remodeling in Patients With Corrected Tetralogy of Fallot

Background The aim of this study was to identify in asymptomatic patients with repaired tetralogy of Fallot the prevalence and determinants of impaired left-sided cardiac function and adverse ventricular remodeling and the relation of left ventricular (LV) dysfunction and remodeling with cardiopulmonary exercise capacity. Methods and Results In a cross-sectional study, 103 patients with tetralogy of Fallot (median age, 16.3 years) in New York Heart Association class 1, with surgical repair at a median age of 1.1 years, and 63 age-matched controls were studied. LV, right ventricular function and geometry, LV myocardial extracellular volume (n=57), and left atrial function were quantified with cardiac magnetic resonance. Peak oxygen consumption was measured by a standardized cardiopulmonary exercise test (n=70). Patients with tetralogy of Fallot had lower LV ejection fraction (P=0.001; 49% below age-adjusted fifth percentile for controls), lower LV mass index (P=0.003), lower LV mass/volume ratio (P<0.01), and impaired left atrial function. Right ventricular mass/volume ratio was the best predictor for LV systolic dysfunction and for a lower LV mass/volume ratio. Compared with controls, LV extracellular volume was higher (P<0.001), particularly in female patients, and associated with subnormal peak oxygen consumption (P=0.037). A peak oxygen consumption below the third percentile reference level was more likely with decreasing LV ejection fraction (P=0.008), and lower LV mass index (P=0.024), but independent of right ventricular ejection fraction. Conclusions In New York Heart Association class 1 patients with tetralogy of Fallot, frequent impaired systolic and diastolic LV function, LV adverse remodeling with LV atrophy, a decreased mass/volume ratio, and extracellular matrix expansion suggest cardiomyopathic changes. The best predictor for LV systolic dysfunction was the right ventricular mass/volume ratio. The subnormal peak oxygen consumption indicates that monitoring of LV status may be important for long-term prognosis.