Cardiac function and obesity

Abstract

Obesity is increasing around the world, and with it the risk of cardiovascular disease Given the rising global epidemic of obesity,1 it is likely that adverse health consequences of excess adiposity will escalate in the future. In this context, several investigators have described the adverse effects of obesity on the heart.2,3 Obesity has been linked to a spectrum of cardiovascular changes ranging from a hyperdynamic circulation,2 through subclinical cardiac structural changes4 to overt heart failure.5 Obesity is associated with haemodynamic overload.2,3 The increased metabolic demand imposed by the expanded adipose tissue and augmented fat-free mass in obesity results in a hyperdynamic circulation with increased blood volume. In addition to the increased preload, left ventricular (LV) afterload is also elevated in obese individuals due to both increased peripheral resistance and greater conduit artery stiffness.6 Right ventricular afterload may be increased, presumably due to associated sleep disordered breathing and LV changes.3 Obesity is associated with atrial and ventricular remodelling (fig 1), known precursors of atrial and ventricular dysfunction, respectively. Obese individuals have larger left atrial size,7 related both to an expanded intravascular volume and to altered LV filling properties (see below). Both eccentric and concentric patterns of LV hypertrophy (LVH) have been described in overweight people,4,8 with the former being more common.8 The extent of cardiac remodelling in obesity increases with its severity and duration,3 and is exacerbated by concomitant …