Abstract 4373171: Progressive Diastolic Dysfunction Detected by Cardiac MRI in Adults with a Systemic Right Ventricle

Abstract

Background: Systemic right ventricular (RV) dysfunction is a major clinical concern in adults with d-transposition of the great arteries (d-TGA) after atrial switch and those with congenitally corrected TGA (ccTGA). While systolic dysfunction has been well characterized, diastolic dysfunction remains poorly understood in this population. Diastolic strain rate, a marker of early myocardial relaxation, may offer insights into subclinical diastolic impairment. We aimed to characterize longitudinal changes in myocardial diastolic strain using cardiac magnetic resonance imaging (MRI). Methods: We retrospectively evaluated baseline and follow-up cardiac MRI studies in 34 adults with a systemic RV (26 with d-TGA post-atrial switch, 8 with ccTGA). The median follow-up interval was 4 years (range: 1–10 years). Global diastolic strain rates (1/s) were derived from feature tracking of steady-state free precession (SSFP) cine sequences in short- and long-axis views, assessing radial, circumferential, and longitudinal directions. Results: Both radial and circumferential global diastolic strain rates significantly declined over time (p ≤ 0.05), consistent with progressive diastolic dysfunction. In contrast, longitudinal global diastolic strain rate remained unchanged. Conclusion: Cardiac MRI-based diastolic strain analysis revealed progressive impairment in radial and circumferential relaxation in adults with a systemic RV, while longitudinal function was preserved. These findings underscore the value of MRI-derived diastolic strain as a potential tool for early detection of dysfunction and longitudinal surveillance in this high-risk population.