Left ventricular hypertrophy and obesity: only a matter of fat?

Abstract

Obesity can be regarded as an energy balance disorder in which inappropriate expansion and dys-function of adipose tissue lead to unfavorable outcomes. Even in the absence of hypertension, adiposity induces structural and functional changes in the heart through hemodynamic and non hemodynamic factors. In the "obese" heart, besides the growth of cardiomyocytes, interstitial fat infiltration and triglyceride accumulation in the contractile elements importantly contribute to left-ventricular mass (LVM) accrual, hypertrophy (LVH) and geometric pattern. In harmony with this, the likelihood of LVH is greater in either obese normotensive or hypertensive individuals than in their non-obese counterparts. Interestingly, recent observations highlight the increasing prevalence of the "concentric" (ie, combined remodeling and hypertrophy), rather than "eccentric" pattern of LV geometry in obesity. Nonetheless, obesity is linked with lack of decrease, or even increase, of LVM over time, independently of blood pressure control and hypertensive treatment. Although obesity-related LV changes result in progressive systolic and diastolic heart failure, the assessment of LVM and LVH in obese individuals still remains a difficult task. In this scenario, it is tempting to speculate that therapeutic interventions for reversal of LVH in obesity should either overcome the "non-hemodynamic" factors or reduce the hemodynamic load. Indeed, weight loss, either achieved by lifestyle changes or bariatric procedures, decreases LVM and improves LV function regardless of blood pressure status. These and other mechanistic insights are discussed in this review, which focuses on "adipose dysfunction" as potential instigator of, and putative therapeutic target for, LVH regression in the setting of obesity.