63 research outputs found

    Left Ventricular Structure and Function Basic Science for Cardiac Imaging

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    The myofiber geometry of the left ventricle (LV) changes gradually from a right-handed helix in the subendocardium to a left-handed helix in the subepicardium. In this review, we associate the LV myofiber architecture with emerging concepts of the electromechanical sequence in a beating heart. We discuss: 1) the morphogenesis and anatomical arrangement of muscle fibers in the adult LV; 2) the sequence of depolarization and repolarization; 3) the physiological inhomogeneity of transmural myocardial mechanics and the apex-to-base sequence of longitudinal and circumferential deformation; 4) the sequence of LV rotation; and 5) the link between LV deformation and the intracavitary flow direction observed during each phase of the cardiac cycle. Integrating the LV structure with electrical activation and motion sequences observed in vivo provides an understanding about the spatiotemporal sequence of regional myocardial performance that is essential for noninvasive cardiac imaging

    Molecular Imaging for Efficacy of Pharmacologic Intervention in Myocardial Remodeling

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    ObjectivesUsing molecular imaging techniques, we examined interstitial alterations during postmyocardial infarction (MI) remodeling and assessed the efficacy of antiangiotensin and antimineralocorticoid intervention, alone and in combination.BackgroundThe antagonists of the renin-angiotensin-aldosterone axis restrict myocardial fibrosis and cardiac remodeling after MI and contribute to improved survival. Radionuclide imaging with technetium-99m–labeled Cy5.5 RGD imaging peptide (CRIP) targets myofibroblasts and indirectly allows monitoring of the extent of collagen deposition post-MI.MethodsCRIP was intravenously administered for gamma imaging after 4 weeks of MI in 63 Swiss-Webster mice and in 6 unmanipulated mice. Of 63 animals, 50 were treated with captopril (C), losartan (L), spironolactone (S) alone, or in combination (CL, SC, SL, and SCL), 8 mice received no treatment. Echocardiography was performed for assessment of cardiac remodeling. Hearts were characterized histopathologically for the presence of myofibroblasts and thick and thin collagen fiber deposition.ResultsAcute MI size was similar in all groups. The quantitative CRIP percent injected dose per gram uptake was greatest in the infarct area of untreated control mice (2.30 ± 0.14%) and decreased significantly in animals treated with 1 agent (C, L, or S; 1.71 ± 0.35%; p = 0.0002). The addition of 2 (CL, SC, or SL 1.31 ± 0.40%; p < 0.0001) or 3 agents (SCL; 1.16 ± 0.26%; p < 0.0001) demonstrated further reduction in tracer uptake. The decrease in echocardiographic left ventricular function, strain and rotation parameters, as well as histologically verified deposition of thin collagen fibers, was significantly reduced in treatment groups and correlated with CRIP uptake.ConclusionsRadiolabeled CRIP allows for the evaluation of the efficacy of neurohumoral antagonists after MI and reconfirms superiority of combination therapy. If proven clinically, molecular imaging of the myocardial healing process may help plan an optimal treatment for patients susceptible to heart failure

    Histopathological maladaptive changes in the explanted human mitral leaflets correlate with changes in echocardiographic leaflet morphology and the severity of ischaemic mitral regurgitation.

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    peer reviewedAIMS: Several changes of the mitral valve (MV) morphology have been previously documented in ischaemic mitral regurgitation (IMR) upon macro and microscopic examination. This study aimed to correlate echocardiographic MV thickening with IMR severity and to delineate the histopathological basis of valve thickening from the explanted leaflets. METHODS AND RESULTS: Two hundred and fifty patients were included in the echo-group; of these, 48 patients (19.2%) underwent surgical mitral valve replacement (MVR), including them in the histology-group. By echocardiography, the thickness of the anterior and posterior leaflet was more extensive in moderate to severe IMR, P < 0.001. Histology-group: patients were divided into two groups based on the median thickness: those with cusp thickness <0.42 cm in Group 1, and ≥0.42 cm in Group 2. The thickness of the base and cusp was more significant in Group 2, P < 0.05 in both. Group 2 biopsies were characterized by involvement of the three leaflet segments, myxoid tissue, and fibrosis deposition. Thicker leaflets were associated with a greater degree of mitral regurgitation (MR), P < 0.0001. In the echo-group, a median leaflet thickness of 3.5 mm of the anterior and posterior MV was independently associated with moderate to severe ischaemic MR [odds ratio (OR) 2.88, P < 0.01] and (OR 10.8, P < 0.001), respectively. CONCLUSION: In ischaemic MR, the thicker the cusps, the worse the MR. Leaflet thickening was due to the myxoid and fibrosis deposition and was detected by echocardiography. Therefore, this method can be helpful in the evaluation of valve remodelling

    Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology.

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    peer reviewedThree-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers
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