Prognostic Value of Left Ventricular Kinetic Energy for Predicting Major Adverse Events in Hypertrophic Cardiomyopathy

BACKGROUND: Hypertrophied left ventricle (LV) in hypertrophic cardiomyopathy (HCM) alters blood flow hemodynamics. OBJECTIVES: The authors aimed to evaluate whether 4-dimensional (4D) flow cardiac magnetic resonance (CMR) parameters can predict major adverse cardiac events (MACE) in HCM. METHODS: This retrospective study included 165 adult HCM patients (mean age 51 years; 115 were male), and 115 normal control subjects with similar age and sex (INITIATE registry). All subjects underwent cine and 4D flow CMR, with LV ejection fraction and maximal left atrial volume calculated from cine images, and LV flow components and kinetic energy (KE) computed from 4D flow CMR. MACE included sudden cardiac death (SCD), aborted SCD, heart failure hospitalization, and stroke. RESULTS: During follow-up (median: 38 months; Q1-Q3: 23-48 months), 30 patients (18%) experienced MACE. Compared with control subjects, HCM patients had reduced LV global KEiEDV (average KE during the cardiac cycle normalized to LV end-diastolic volume), and even lower in HCM with MACE. LV global KEiEDV provided incremental value over cine imaging (maximal left atrial volume and LV ejection) and late gadolinium enhancement in predicting HCM with MACE. KEiEDV ≤ 6.37 μJ/mL was an independent predictor of MACE in Cox regression analysis (HR: 4.12; 95% CI: 2.00-8.47) and remained significant after adjusting for age, NYHA functional class III/IV, family history of SCD, cine imaging, and late gadolinium enhancement extent (adjusted HR: 3.49 95% CI: 1.67-7.30 to 4.50 95% CI: 2.15-9.40; all P < 0.01). CONCLUSIONS: We found that 4D flow-derived LV global KEiEDV was significantly reduced in HCM with MACE, which could provide incremental prognostic value for clinical risk stratification. (Integrated Computation Modeling of Right Heart Mechanics and Blood Flow Dynamics in Congenital Heart Disease INITIATE; NCT03217240).