Abstract 17333: Novel Evidence of the Coronary Microvascular Steal Phenomenon in Hypertrophic Cardiomyopathy - A Quantitative Stress Perfusion Cardiovascular Magnetic Resonance Study

Background: Hypertrophic cardiomyopathy (HCM) is associated with microvascular ischemia. Mechanisms include reduced coronary arteriolar density and intima-medial thickening, particularly in the endocardium. However, the severity and spatial distribution of ischemia are unclear. Our aim was to assess the pattern of microvascular ischemia quantitatively using stress perfusion cardiovascular magnetic resonance (CMR). Methods: HCM patients (n=28, mean±SD age 57±14 years, 19 male) with no significant coronary disease were studied. First-pass CMR perfusion imaging was undertaken during adenosine-induced hyperemia (140µg/kg/min) and at rest using a hybrid echo-planar imaging sequence (3 slices). After image registration, a modified Fermi-constrained deconvolution algorithm was applied pixel-wise to calculate absolute blood flow (Fig 1). From these pixel maps, regions of interest (ROI) in hypoperfused and hyperemic myocardium were identified at stress and compared with corresponding areas at rest. The myocardium ...