Children with repaired tetralogy of Fallot, double-outlet right ventricle, or truncus arteriosus who underwent CMR and echocardiography within a 4-week interval were retrospectively studied. From the four-chamber view, indexed RV lateral wall length, indexed RV end-diastolic perimeter length, and indexed RV end-diastolic area (RVEDAi), were measured. Results were compared with CMR indexed RV volume. The sensitivity and specifity of echocardiographic threshold values predicting RV volumes < 170 mL/m2 were determined.
Fifty-one children (mean age, 12.7 ¡À 3.5 years; 25 male, 26 female) were reviewed. RVEDAi was correlated with CMR indexed RV volume (r?= 0.60, P < .0001). Indexed RV end-diastolic perimeter length and indexed RV lateral wall length were not correlated with CMR. RVEDAi < 20 cm2/m2 had 100 % specificity to predict indexed RV volume ?170 mL/m2 (area under the curve, 0.79), reducing the need for CMR in 15 of 51 patients (29 % ). A threshold RVEDAi of 22 cm2/m2 would reduce the need for CMR in 21 of 51 patients (41 % ) at the expense of one false-negative result. The coefficients of variation were 14.7 % for intraobserver variability and 9.6 % for interobserver variability.
The specificity of echocardiography-measured RVEDAi can be set to predict RV volumes below a 170 mL/m2 threshold in 100 % of cases. This may reduce the need for CMR to determine RV volumes in ?5 % of patients with congenital heart disease, potentially reducing patient burden and costs.