Hypertrophic Cardiomyopathy Is Associated with Altered Left Ventricular 3D Blood Flow Dynamics

Abstract

To employ four-dimensional (4D) flow MRI to investigate associations between hemodynamic parameters with systolic anterior motion (SAM), mitral regurgitation (MR), stroke volume, and cardiac mass in patients with hypertrophic cardiomyopathy (HCM). Materials and Methods: A total of 13 patients with HCM (51 years ± 16 [standard deviation]; 10 men) and 11 age-matched healthy control subjects (54 years ± 15; eight men) underwent cardiac 4D flow MRI data analysis including calculation of peak systolic and diastolic control-averaged left ventricular (LV) velocity maps to quantify volumes of elevated velocity (EVV) in the left ventricle. Standardof-care cine imaging was performed in short-axis, LV outflow tract (LVOT), and two-, three-, and four-chamber views on which the presence of SAM, presence of MR, total stroke volume, and cardiac mass were assessed. Results: Systolic EVV in patients with HCM was 7 mL ± 5, which was significantly associated with elevated aortic peak velocity (R = 0.87; P < .001), decreased LVOT diameter (R = 0.68; P = .01), and increased cardiac mass (R = 0.62; P = .02). In addition, EVV differed significantly between patients with and those without SAM (10 mL ± 4.7 vs 3 mL ± 2.3; P = .03) and those with and those without MR (9.9 mL ± 4.8 vs 4.0 mL ± 3.2; P < .05). In the atrial systolic phase, peak diastolic velocity in the LV correlated with septal thickness (R = 0.66; P = .01). Conclusion: Quantification and visualization of EVV in the LV is feasible and may provide further insight into the clinical manifestations of altered hemodynamics in HCM.

The Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Hypertrophic Cardiomyopathy

“…One of the uses of phase-contrast MRI includes assessing obstructive HCM, a common disease subtype, characterized by thickening of the interventricular septum and associated with systolic anterior motion (SAM) of the mitral valve, in which the leaflets, during mid-systole, contact or near contact the septum. A component of HCM that is also often not highlighted as much in literature is aortic stiffness, with the LVOT-to-ascending aorta (AAo) diameter ratio correlating with the outflow gradient [ 82 ]. The degree of LVOT obstruction is necessary to evaluate, as it is associated with structural disadvantages that include diastolic dysfunction and reduced LV compliance, leading to adverse cardiovascular events such as heart failure, stroke, and SCD [ 83 ].…”

Comparing long‐term outcomes of septal myectomy and mitral valve replacement in hypertrophic cardiomyopathy patients: A retrospective cohort study in Iran

“…Moreover, postoperative echocardiograms indicated acceptable LVOT gradient and IVS reductions in all three groups. Although patients receiving a septal myectomy procedure had the most significant reduction in LVOT gradient, MVR was also associated with a relative decrease in LVOT gradient, which can be attributed to the Normalization of LV Geometry, 39 improved blood flow dynamics, 40 and a reduction in Valve‐Septum Contact 6 …”

Direct mitral regurgitation quantification in hypertrophic cardiomyopathy using 4D flow CMR jet tracking: evaluation in comparison to conventional CMR

“…Patients were identified by a retrospective chart review approved by the Institutional Review Board (IRB). Patients included in this study were previously reported in prior publications [ 16 – 18 ], none of which assessed direct MR quantification with 4D flow CMR.…”