Methods Results

Downloatolerated and was not associated with increased LV diastolic stiffness. Conclusions In HF dogs, circumferential augmentation of LV wall thickness with AHI improves LV structure and function. The results support continued development of AHI for the treatment of patients with advanced HF. (J Am Coll Cardiol HF 2013;1:252–8) ª 2013 by the American College of Cardiology Foundation Despite considerable progress over the past 3 decades in the development and availability of drugs and devices for treating heart failure (HF) (1), the incidence of HF continues to increase and has, by all counts, reached epidemic proportions. During the course of evolving HF, the left ventricle (LV) progressively enlarges and its shape transforms from elliptical to one that more closely approximates a sphere (2). These structural changes promote worsening HF symptoms and predict poor long-term outcome (3). An important contributor to progres-sive LV systolic dysfunction in HF and supported by Laplace’s law, is elevation of LV wall stress that results from progressive LV enlargement and wall thinning. Wall stress or tension is a major determinant of myocardial oxygen consumption (MVO2). Structural LV change