Assessment of systemic right ventricular (RV) function is a key point in the follow-up of patients with transposition of the great arteries (TGA). Current echocardiographic assessment of RV function is at best an estimate, and cardiac magnetic resonance (CMR) is considered the gold standard. However, this technique is expensive, has limited availability, and requires significant expertise to acquire and interpret the images. The myocardial performance index (MPI) has recently been studied for assessment of pulmonary RV function and shows promise as a simple yet powerful tool for assessing patients with RV dysfunction of various origins. We set out to compare MPI and CMR assessment of systemic RV function in patients with TGA.
Methods and Results—
Data from patients with TGA (11 with congenitally corrected TGA, 18 with surgically corrected TGA) who had CMR within 6 months of their echocardiogram were reviewed. The average systemic RV ejection fraction (RVEF) by CMR was 39.4±11.4%, and the systemic RVMPI for this group was 0.56±0.21. There was a strong negative correlation between the systemic RVMPI and systemic RVEF by CMR (
<0.01). The systemic RVEF can be estimated from this formula: RVEF=65%−(45.2×MPI).
MPI can be used in patients with systemic RVs to assess global function and to estimate an EF with good accuracy.