Right ventricular free wall strain predicts functional capacity in patients with repaired Tetralogy of Fallot

To investigate the role of right ventricular free wall strain (RVFWSL) to predict low functional capacity in repaired tetralogy of Fallot (rTOF). We prospectively enrolled 33 patients with rTOF with moderate to severe PR who underwent rest and peak exercise echocardiography on a semisupine cycloergometer. Conventional function and strain imaging parameters of both ventricles were measured. Patients performing < 7 METS were defined to have low functional capacity. Logistic regression was used to identify parameters associated with low functional capacity. Eleven patients (33.3%) had low functional capacity. These patients were shorter (height 155 ± 7 vs 163 ± 9 cm, p = 0.023), more frequently female (27.3 vs 72.7%, p = 0.024) and had history of Blalock-Taussig shunt (45.5 vs 9.1%, p = 0.027). On multivariate analysis RVFWSL was the only predictor of low functional capacity OR 1.39 (CI 95%, 1.06-1.83., p = 0.018) per % change. A RVFWSL < 17% (absolute value) had an AUC of 0.785, sensitivity of 81.8% and specificity of 77.3% to predict low functional capacity. Right ventricular free wall strain is an independent predictor of low functional capacity in repaired tetralogy of Fallot with moderate to severe PR. A value < 17% might be useful in deciding when to perform pulmonary valve replacement, when functional capacity cannot be objectively measured.