Evaluation of the systemic right ventricle in transposition of the great arteries using fast strain encoded cardiovascular magnetic resonance

BACKGROUND AND AIMS: Patients with a systemic right ventricle (SRV) experience increased morbidity and mortality, highlighting the need for precise assessment of systolic function. Fast Strain-ENCoded imaging (fSENC) is a novel strain measurement method that allows early detection of cardiac impairment and has demonstrated significant diagnostic and prognostic value. This study aimed to evaluate global and regional cardiac function using fSENC in patients with SRV due to transposition of the great arteries following Senning/Mustard repair (TGA) or congenitally corrected TGA (ccTGA). METHODS: In this prospective, single-center study, patients with SRV underwent conventional cardiovascular magnetic resonance (CMR), including feature tracking (FT) strain and fSENC imaging between October 2022 and November 2023. Age- and sex-matched healthy controls were recruited. fSENC was acquired in a single heartbeat per slice to assess global longitudinal and circumferential strain (GLS, GCS) and segmental strains. Laboratory values, including N-terminal pro-hormone brain natriuretic peptide (NT-pro BNP), and a 6-minute walk test (6MWT) were obtained in SRV patients. RESULTS: A total of 26 patients (19 males (73.1%), median age 40 (34 - 49)years) and 26 controls were included. SRV patients had a median NT-pro BNP of 380 (215-667) ng/L and reduced SRV ejection fraction (EF 42.8 ± 8.8%) with chamber dilation. Segmental fSENC strain analysis revealed significantly lower strain values in SRV patients compared with controls, particularly in septal and anterior segments (strain ≥ -17%). Correlation of fSENC-derived GLS and GCS with FT metrics and NT-pro BNP levels was moderate (r = 0.4 for both), whereas EF and 6MWT showed no significant correlation with FT metrics or NT-pro BNP levels. CONCLUSION: This is the first study to comprehensively assess both regional and global strains using fSENC in SRV patients. fSENC enables reproducible assessment of myocardial deformation and shows moderately strong agreement with established strain methods. Its association with NT-pro BNP suggests potential clinical relevance, warranting further studies to evaluate its role in longitudinal monitoring and prognostic assessment.