Effects of Individual and Coexisting Diabetes and Cardiomyopathy on Diastolic Function in Rats (Rattus norvegicus domestica)

The goal of this study was to evaluate diastolic intraventricular pressure gradients (IVPG) and 2-dimensional tissue tracking (2DTT) patterns during diabetes and cardiomyopathy. Rats (n = 60) were induced to become diabetic (DM group, n = 15) by using streptozotocin, to become cardiomyopathic (CM group, n = 15) by using isoproterenol, and to become both diabetic and cardiomyopathic (DMCM group, n = 15); control rats (CT group, n = 15) were injected with saline. Two months after induction, all rats underwent conventional echocardiography, IVPG, and 2DTT and then were euthanized for microscopic examination of cardiac fibrosis. Compared with the controls, all 3 treated groups showed diastolic dysfunction and delayed cardiac relaxation. DMCM rats showed the most pronounced cardiac abnormalities. In addition, CM and DMCM groups had showed decreased middle IVPG, whereas DMCM rats had decreased midapical IVPG. Although the overall IVPG of the CM group was normal, the middle segment was significantly decreased. 2DTT results showed that the DMCM group had a delay in relaxation compared with other groups. IVPG and 2DTT can be used to overcome the limitation of conventional echocardiographic methods and reveal diastolic dysfunction. DM worsened diastolic function during cardiac disease.

Abstract 20360: MRI Assessment of Diastolic and Systolic Intraventricular Pressure Gradients in Heart Failure

Background: Non-invasive assessment of left ventricular (LV) diastolic function is an important goal to better understand physiologic abnormalities in heart failure. The spatiotemporal pattern of LV blood flow velocities during early filling can be used to estimate intraventricular pressure gradients driving early filling. MRI can provide accurate flow velocity information in the LV, but this method has not been exploited to assess diastolic function in heart failure (HF). Aim: To assess differences in intraventricular pressure gradients in heart failure and preserved ejection fraction (HFPEF) and heart failure with reduced ejection fraction (HFREF), compared to subjects without HF. Methods: We studied 23 subjects without HF, 13 subjects with HFREF and 14 subjects with HFPEF. Intraventricular flow during diastole was measured using 2D in-plane phase-contrast MRI. We solved the Eulier equations to compute intraventricular pressure gradients during LV early filling (figure) and during ejection. Results: Whereas the initial velocity of wave propagation (was not significantly different between the groups, the terminal diastolic propagation velocity during early diastolic filling was significantly slower (P=0.004) in HFREF (5.2 m/s; 95%CI=3.9-6.8) than in patients with HFPEF (9.5; 95%CI=6.6-13.6) or subjects without HF (8.9; 95%CI=7.3-10.7). In contrast, HFPEF was associated with a greater amplitude of the reversal of the base-to-apex intraventricular pressure gradient during early filling (β=-0.34; P=0.04), which was driven by the inertial component. Conclusions: HFPEF and HFREF are associated with distinct patterns of intraventricular pressure gradient abnormalities during early diastolic filling. Our findings support fundamental differences in the nature of diastolic dysfunction in these 2 conditions.

A Rare Case of Hypertrophic Cardiomyopathy with Subendocardial Late Gadolinium Enhancement in an Apical Aneurysm with Thrombus

The mechanisms responsible for the development of apical aneurysms in cases of hypertrophic cardiomyopathy (HCM) are currently unclear but likely involve multiple factors. Here, we present a case of HCM with marked subendocardial fibrosis involving the apical and proximal portions of the left ventricle. A 71-year-old man with left ventricular hypertrophy presented with signs and symptoms of heart failure. The presence of asymmetrical left ventricular hypertrophy and bilateral, thickened ventricular walls with an apical aneurysm on transthoracic echocardiography suggested a diagnosis of HCM with ventricular dysfunction. No intraventricular pressure gradients with obstruction were identified. Late gadolinium enhancement (LGE) with cardiac magnetic resonance imaging and endomyocardial biopsies showed subendocardial fibrosis involving the apical aneurysm and proximal portion. Whereas LGE in a transmural pattern is commonly observed in HCM apical aneurysms, subendocardial LGE, as noted in the present case, is a relatively rare occurrence. Thus, the present case may provide unique insights into the adverse remodeling process and formation of apical aneurysms in cases of HCM.