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Background: The pacing model of heart failure produces heterogeneous changes in wall stress and myocyte diameter. The purpose of this study was to measure regional changes in cardiotrophin-1 (CT-1), a cytokine thought to play a role in LV remodeling, and regional changes in LV strain as measured with magnetic resonance imaging. Materials and methods: Dilated cardiomyopathy was induced in nine mongrel dogs over 4 wk by rapid pacing using a right ventricular epicardial lead. Baseline CT-1 was measured from an apical myocardial biopsy, and regional CT-1 was measured from anterior, lateral, inferior, and septal walls after the induction of heart failure and in six control dogs. Tissue tagged images were divided into similar regions and minimal principal strain (MPS), ejection fraction, and ventricular volumes were compared after induction of heart failure. Results: After induction of heart failure, LV ejection fraction and end-diastolic volume differed significantly from baseline (P < 0.01 and P = 0.02, respectively). Additionally, regional CT-1 and MPS were significantly different (P < 0.01 for both). Cardiotrophin-1 increased significantly in the inferior and septal walls (both P < 0.01) but not in the anterior or lateral walls (both P = NS). Minimum principal strain decreased significantly in the inferior and septal walls (both P < 0.01) but not in the anterior or lateral walls (both P = NS). Conclusion: The pacing model of heart failure produces heterogeneous changes in regional CT-1 and wall motion as measured by MPS. The greatest regional changes are closest to the pacemaker site: the inferior and septal walls. These differences in regional CT-1 may account for previously noted myocyte hypertrophy and preserved ventricular function in these regions. [Copyright &y& Elsevier]

: BackgroundCoronary artery disease characteristically impacts left ventricular (LV) function on a regional basis, although ultimately global function may be affected as well. Echocardiography is commonly clinically used for the assessment of regional function; however, it is only semiquantitative and in its current iteration is only two-dimensional in nature. Magnetic resonance imaging (MRI) with tissue tagging offers the possibility for noninvasive, three-dimensional (3D) assessment of transmural and segmental left ventricular strain and, thereby, function. Accordingly, we have explored methodologies to accurately and quantitatively characterize regional systolic function in three dimensions in patients with ischemic heart disease using MRI.: Materials and methodsMRI radiofrequency tissue tagging was performed at rest and during dobutamine administration (10 mg/kg/min) on 10 normal volunteers (age: 26 ± 6) and 8 patients with severe ischemic cardiomyopathy (age: 60 ± 5, EF 26 ± 11%). Three-dimensional global and regional systolic strain calculations were made based on 3D myocardial point displacements and compared with conventional measures.: ResultsGlobal left ventricular strains were significantly decreased in ischemic patients at rest (0.14 ± 0.04 versus 0.25 ± 0.02, P < 0.001) and with dobutamine (0.14 ± 0.03 versus 0.29 ± 0.03, P < 0.001). In the regional analysis (216 LV wall segments) this methodology accurately differentiated normal from abnormally contracting regions.: ConclusionsNoninvasive dobutamine MRI tissue tagging with calculation of 3D regional strains has significant promise as a clinical tool which is capable of the identification, quantification, and display of regionally varying ventricular function. [Copyright &y& Elsevier]