title: Myocardial oxygen consumption change predicts left ventricular relaxation improvement in obese humans after weight loss.
abstract: Obesity adversely affects myocardial metabolism, efficiency, and diastolic function. Our objective was to determine whether weight loss can ameliorate obesity-related myocardial metabolism and efficiency derangements and that these improvements directly relate to improved diastolic function in humans. We studied 30 obese (BMI >30 kg/m2) subjects with positron emission tomography (PET) (myocardial metabolism, blood flow) and echocardiography (structure, function) before and after marked weight loss from gastric bypass surgery (N = 10) or moderate weight loss from diet (N = 20). Baseline BMI, insulin resistance, hemodynamics, left ventricular (LV) mass, systolic function, myocardial oxygen consumption (MVO2), and fatty acid (FA) metabolism were similar between the groups. MVO2/g decreased after diet-induced weight loss (P = 0.009). Total MVO2 decreased after dietary (P = 0.02) and surgical weight loss (P = 0.0006) and was related to decreased BMI (P = 0.006). Total myocardial FA utilization decreased (P = 0.03), and FA oxidation trended lower (P = 0.06) only after surgery. FA esterification and LV efficiency were unchanged. After surgical weight loss, LV mass decreased by 23% (Doppler-derived) E/E' by 33%, and relaxation increased (improved) by 28%. Improved LV relaxation related significantly to decreased BMI, insulin resistance, total MVO2, and LV mass but not FA utilization. Decreased total MVO(2) predicted LV relaxation improvement independent of BMI change (P = 0.02). Weight loss can ameliorate the obesity-related derangements in myocardial metabolism and LV structure and diastolic function. Decreased total MVO2 independently predicted improved LV relaxation, suggesting that myocardial oxygen metabolism may be mechanistically important in determining cardiac relaxation.
authors: Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St Louis, Missouri, USA.
authors: C Huie
authors: CH
authors: Lin
authors: Suraj
authors: S
authors: Kurup
authors: Pilar
authors: P
authors: Herrero
authors: Kenneth B
authors: KB
authors: Schechtman
authors: J Christopher
authors: JC
authors: Eagon
authors: Samuel
authors: S
authors: Klein
authors: Víctor G
authors: VG
authors: Dávila-Román
authors: Richard I
authors: RI
authors: Stein
authors: Gerald W
authors: GW
authors: Dorn
authors: Robert J
authors: RJ
authors: Gropler
authors: Alan D
authors: AD
authors: Waggoner
authors: Linda R
authors: LR
authors: Peterson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003131:Combined Modality Therapy; D004038:Diet, Reducing; D015150:Echocardiography, Doppler; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009126:Muscle Relaxation; D009206:Myocardium / Q000378:metabolism*; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism* / Q000503:physiopathology*; D009767:Obesity, Morbid / Q000178:diet therapy / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery; D010101:Oxygen Consumption; D049268:Positron-Emission Tomography; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000517:prevention & control; D016277:Ventricular Function, Left; D015431:Weight Loss