Obesity Promotes Left Ventricular Concentric Geometric Remodeling and Hypertrophy Independent

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OBESITY PROMOTES LEFT VENTRICULAR CONCENTRIC GEOMETRIC REMODELING AND HYPERTROPHY INDEPENDENT OF BLOOD PRESSURE

G.R. Norton1, C. Libhaber1,2, O.H.I. Majane1, E. Libhaber1,2, M.J. Maseko1,

M.R. Essop2, P. Sareli1, A.J. Woodiwiss1

1School of Physiology, University of the Witwatersrand, Johannesburg, South Africa, 2School of Medicine, Chris Hani-Baragwanath Hospital, 3University of the Witwatersrand, Johannesburg, South Africa

Objectives: To determine whether excess adiposity promotes eccentric or concentric left ventricular (LV) geometric changes and the mechanisms thereof.

Background: The principle mechanisms that should be targeted to treat obesity-induced LV hypertrophy (LVH) remain obscure. Consistent with obesity-induced increases in blood volume and cardiac preloads, some studies suggest that obesity promotes eccentric remodeling. In contrast, consistent with adiposity-induced increases in LV afterload, other studies indicate that adiposity is associated with concentric LV remodeling.

Methods and Results: We assessed the relations between waist circumference (WC) and LV mean wall thickness (MWT=posterior+septal wall thickness), LV relative wall thickness (RWT=MWT/end diastolic internal diameter [EDD]), concentric LVH (LV mass index [LVMI]>51g/m2.7 & RWT>0.45), eccentric LVH (LVMI>51g/m2.7 & RWT<0.45), or concentric LV remodeling (normal LVMI & RWT>0.45), in 309 never-treated, randomly recruited adult participants with a high prevalence of excess adiposity (25% overweight & 38% obese). Pulse wave analysis was performed to determine central artery blood pressures (BP). 231 participants had high quality ambulatory BP monitoring. 7% of participants had concentric LVH, 16% concentric LV remodeling, and 15% eccentric LVH. With adjustments for potential confounders including conventional systolic BP (SBP) in the model, WC was related to MWT (p=0.0001), RWT (p<0.03), concentric LVH (p<0.02) and concentric LV remodeling (p<0.04), but not with LVEDD or eccentric LVH. Similar outcomes were noted with adjustments for central or 24-hour SBP, and for conventional, central or 24-hour pulse pressure.

Conclusions: Excess adiposity promotes primarily concentric geometric LV changes and LVH an effect which is not accounted for by BP.