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 index (r=0.34), and inversely with aortic distensibility (r=-0.24) and LV filling parameters (r=-0.28 to -0.31). Hypertensive participants had significantly higher BSC values (p<0.001). BSC independently predicted incident hypertension in both sexes (females: HR 1.17; males: HR 1.10), with the strongest effects in those under 65 years (females: HR 1.33; males: HR 1.30). BSC predicted MACE in males (HR 1.10). Participants with low BSC and low basal septum thickness showed a 4-fold lower 5-year hypertension incidence compared to those with high values in both measures (5-year survival 98.2% vs 93.1%). Basal septum thickness emerged as the stronger prognostic marker for long-term composite cardiovascular events.
Conclusion: CMR-derived BSC provides a reliable, quantitative biomarker for early detection of hypertensive cardiac remodelling, preceding overt BSH. Its independent prediction of incident hypertension and cardiovascular events supports its use alongside conventional assessments for risk stratification in hypertensive heart disease.