Effects of Obesity and Weight Loss on Cardiac Function and Valvular Performance

OBJECTIVE: To study the consequences of long-standing obesity on myocardial function and valvular performance and to determine the effects of weight loss on these cardiovascular features. RESEARCH METHODS AND PROCEDURES: We included 41 patients with obesity referred for weight-reducing gastroplasty, 31 patients with obesity who received dietary recommendations, and 43 lean subjects. Body weight and blood pressure were measured, and cardiac function and valvular performance were estimated echocardiographically. Left ventricular ejection fraction was used to assess systolic heart function, and the ratio of transmitral early to atrial (E/A) peak flow velocity was used as an estimate of diastolic filling. All three study groups were investigated at baseline, and the two groups with obesity were re-examined at 1-year follow-up. RESULTS: Patients with obesity had higher blood pressure, greater cardiac output, lower ejection fraction, and reduced E/A ratio, compared with lean subjects (p<0.01). Surgical treatment of obesity led to significant decreases in body weight, whereas body weight remained unchanged in the group treated with dietary recommendations (p<0.001). In the weight loss group, blood pressure and cardiac output decreased and the E/A ratio increased (p<0.001). Left ventricular ejection fraction tended to increase in the weight loss group and decrease in the obese control group (p<0.01). No significant valvular disease was observed in any of the subjects with obesity at baseline or after weight loss. DISCUSSION: We conclude that weight reduction in subjects with obesity is associated with improvements in left ventricular diastolic filling and has favorable effects on left ventricular ejection fraction. Neither obesity nor weight loss seem to promote valvular heart disease.