Pressure unloading represents the only effective therapy in increased afterload-induced left ventricular hypertrophy (LVH) as it leads to myocardial reverse remodeling (reduction of increased left ventricular mass, attenuated myocardial fibrosis) and preserved cardiac function. However, the effect of myocardial reverse remodeling on cardiac mechanoenergetics has not been elucidated. Therefore, we aimed to provide a detailed hemodynamic characterization in a rat model of LVH undergoing pressure unloading. Pressure overload was induced in Sprague-Dawley rats by abdominal aortic banding for 6 (AB 6th week) or 12 weeks (AB 12th week). Sham operated animals served as controls. Aortic debanding procedure was performed after the 6th experimental week (debanded 12th week) to investigate the regression of LVH. Pressure unloading resulted in significant reduction of LVH (heart weight/tibial length ratio: 0.38±0.01 vs. 0.58±0.02g/mm, cardiomyocyte diameter: 18.3±0.1 vs. 24.1±0.8µm debanded 12th week vs. AB 12th week, p<0.05), attenuated the extracellular matrix remodeling (Masson's score: 1.37±0.13 vs.1.73±0.10, debanded 12th week vs. AB 12th week, p<0.05), provided protection against the diastolic dysfunction and reversed the maladaptive contractility augmentation (slope of end-systolic pressure-volume relationship: 1.39±0.24 vs. 2.04±0.09mmHg/μl, p<0.05 debanded 12th week vs. AB 6th week, p<0.05). In addition, myocardial reverse remodeling was also associated with preserved ventriculo-arterial coupling and increased mechanical efficiency (50.6±2.8 vs. 38.9±2.5%, debanded 12th week vs. AB 12th week p<0.05) indicating a complete functional and mechanoenergetic recovery. According to our best knowledge, this is the first study demonstrating that the regression of LVH is accompanied by maintained cardiac mechanoenergetics.
- Pressure overload-induced cardiac hypertrophy
- pressure unloading
- cardiac contractility
- cardiac mechanoenergetics
- pressure-volume analysis
- Copyright © 2016, American Journal of Physiology - Heart and Circulatory Physiology