Aim
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, including feature tracking (FT) strain and fSENC imaging between 2022 and 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 NT-proBNP, and a 6-minute walk test (6MWT) were obtained in SRV patients. Intra- and inter-rater reliability testing was performed by calculating intraclass correlation coefficients (ICC).
Results
A total of 26 patients and 26 controls were included (19 males (73.1%), age 42±11 years, in both groups). Fourteen SRV patients (53.8%) received heart failure medication. SRV patients had a median NT-proBNP of 380 (215–667) ng/L and reduced SRV ejection fraction (EF 42.8±8.8%) with chamber dilation (EDV/BSA 114.9±29.5 ml/m²). Patients with ccTGA had significantly better SRV ejection fraction than those with TGA (48.3±6.7% vs. 39.4±8.3%, p=0.01). FT strain showed impaired longitudinal, circumferential, and radial deformation in SRV patients (FT-GLS -13.5±3.7%, FT-GCS -12.6±3.0%, FT-GRS 21.3±6.5%). Similarly, fSENC-GLS and -GCS were significantly impaired (fSENC-GLS -13.5±3.7%, GCS -12.6±3.0%). Segmental fSENC analysis revealed significantly lower strain values in SRV patients, particularly in septal and anterior segments (-14.8±2.8% and -14.2±3.3%). Correlation between FT and fSENC strain was moderately strong (r=0.6 for FT-GLS vs. fSENC-GLS, p=0.003; r=0.6 for FT-GCS vs. fSENC-GCS, p=0.003). Only fSENC-GLS and -GCS correlated with NT-proBNP (r=0.4 each, p=0.03 and 0.04), whereas FT strain, EF, and 6MWT did not. Inter- and intraobserver reproducibility was excellent, with ICC for fSENC-GLS of 0.99 (95% CI 0.97–0.99) and 0.99 (95% CI 0.96–0.99), respectively.
Conclusion
This is the first study to comprehensively assess 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-proBNP suggests potential clinical relevance, warranting further studies to evaluate its role in longitudinal monitoring and prognostic assessment.
