Left ventricular function and cardiopulmonary performance following surgical treatment of morbid obesity.

BACKGROUND: It is well established that morbid obesity affects the respiratory system and the diastolic function of the heart. During exercise, cardiopulmonary reserve is exhausted because of augmented requirements, leading to a significant intolerance. A study was undertaken to investigate the influence of body weight loss on the characteristics of the left ventricle (LV) and on exercise capacity in obese patients before and 6 months, following vertical banded gastroplasty (VBG).
METHODS: 16 morbidly obese individuals (BMI > 40 kg/m2) scheduled for VBG were studied. A symptom-limited cardiopulmonary exercise test and a complete transthoracic echocardiogram were performed 1 day before operation and 6 months postoperatively (after the patients achieved a body weight loss of > 20% of their pre-operative values).
RESULTS: Exercise duration increased significantly 6 months following surgery. The mean O2 consumption at peak exercise (peak VO2) and at the anaerobic threshold (VO2AT) was significantly higher after weight loss. 6 months after VBG the LV thickness decreased significantly. Regarding the diastolic indices, isovolumic relaxation time (IVRT) and early/late (E/A) velocity ratio, there was a significant improvement after weight loss. Simple linear regression analysis revealed that peak VO2 and VO2AT were significantly correlated with IVRT and E/A velocity ratio.
CONCLUSIONS: Weight loss after VBG improves the cardiac diastolic function and this is associated with an improvement in cardiopulmonary exercise performance. Left ventricular filling variables could be considered among the most important determinants of exercise intolerance in obese individuals.