Introduction: Basal septal hypertrophy (BSH), defined as thickening of the upper interventricular septum, occurs in up to 20% of hypertensive patients. Geometric changes in the basal septum may precede overt BSH, yet no robust quantitative marker exists for early detection. We investigated whether basal septal curvature (BSC), derived from cardiovascular magnetic resonance (CMR), captures early hypertensive remodelling and predicts incident cardiovascular events.
Methods: We analysed 38,830 UK Biobank imaging participants using automated methods to measure average BSC from a 3D shape model. BSC was correlated with cardiac structural and functional parameters, and survival regression models assessed its association with incident hypertension and major adverse cardiovascular events (MACE).
Results: BSC correlated with basal septum thickness (r=0.39), age (r=0.35), and LV remodelling (r=0.34), and inversely with aortic distensibility, LA reservoir volume and LV filling (r=-0.24 to -0.31) (p<0.001 for all). Hypertensive participants had higher BSC (p<0.001). BSC independently predicted incident hypertension in both sexes (HR 1.10–1.33, strongest under 65, p<0.05) but was not independently associated with incident MACE. Low BSC/low septal thickness was associated with a 4-fold lower 5-year hypertension incidence than high values in both (98.2% vs 93.1%). Septal thickness remained the stronger predictor of long-term events.
Conclusion: CMR-derived BSC is a reliable early biomarker of hypertensive cardiac remodelling that independently predicts incident hypertension, while basal septal thickness remains the stronger marker of subsequent cardiovascular events; together they may complement conventional risk stratification.