Effect of Weight Loss on Myocardial Metabolism and Cardiac Relaxation in Obese Adults

Effect of Weight Loss on Myocardial Oxygen Consumption and Left Ventricular Relaxation in Obese Adults

Obesity adversely affects myocardial (muscular heart tissue) metabolism, efficiency, and diastolic function. The objective of this study was to determine if weight loss could improve obesity-related myocardial metabolism and efficiency and if these improvements were directly related to improved diastolic function.

This was a prospective, interventional study in obese adults ages 21 to 50 years of age to determine whether weight loss could improve obesity-related myocardial metabolism and efficiency. Two different mechanisms of weight loss were studied: diet and exercise and gastric bypass surgery. Positron emission tomography (PET) was used to quantitate myocardial oxygen consumption (MVO2) and myocardial fatty acid (FA) metabolism. Echocardiography with tissue Doppler imaging was used to quantify cardiac structure, systolic and diastolic function (left ventricular (LV) relaxation (E') and septal ratio (E/E')).

Inclusion Criteria:

• Body mass index (BMI) > 30 kg/m^2
• Sedentary lifestyle

Exclusion Criteria:

• Body weight >159 kg
• Insulin-requiring diabetes
• Heart failure
• History of coronary artery disease
• Chest pain
• Untreated sleep apnea
• Being an active smoker
• Pregnant, lactating, or postmenopausal