Cardiovascular magnetic resonance-derived metrics as diagnostic markers for left ventricular outflow tract obstruction in hypertrophic cardiomyopathy

BACKGROUND: This study aims to assess the utility of cardiovascular magnetic resonance (CMR)-derived measurements as diagnostic indicators for left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) patients, using Doppler echocardiography as the reference method. METHODS: In this single-center retrospective cross-sectional study, adult HCM patients with transthoracic echocardiography and CMR within a 6-month time window were enrolled. Doppler LVOT gradient was measured both at rest and under provocative maneuvers. LVOTO was defined as a gradient ≥30 mmHg. The total cohort was randomly divided into a training (80%) and validation (20%) cohorts, maintaining the same proportions of patients with and without LVOTO in both cohorts. In CMR, all measurements were performed in the three-chamber balanced steady-state free precession cine images. CMR metrics were examined in relation to LVOTO by means of multivariable logistic regression models. RESULTS: , a sensitivity of 97% and a negative predictive value of 97%. The minimum MV-IVSi distance showed excellent intra- and inter-observer reproducibility with an intraclass correlation coefficient of ≥0.95. CONCLUSION: CMR-derived parameters, particularly the minimum MV-IVSi distance, can accurately identify LVOTO in HCM patients and easily be integrated into a standard CMR analysis.