LEFT-VENTRICULAR FUNCTION-RESPONSE TO EXERCISE IN NORMOTENSIVE OBESE SUBJECTS - INFLUENCE OF DEGREE AND DURATION OF OBESITY

This study has been designed to evaluate whether duration and severity of obesity can influence left ventricular function response to exercise in obese subjects without other known cardiovascular risk factors such as hypertension, diabetes or hyperlipoproteinemia. A total of 29 obese subjects were included and they were divided, according to their body mass index and to Garrow's criteria as follows: Overweight or mildly obese subjects: body mass index from 25 to 30 kg/m2; moderately obese subjects: body mass index > 30 and < 40 kg/m2. Both obese groups were further subdivided according to their duration of obesity evaluated by accurate anamnesis in subgroup A (duration of obesity less than 120 months) and subgroup B (duration of obesity more than 120 months). Left ventricular ejection fraction was detected by blood pool gated radionuclide angiocardiography both at rest and after symptom-limited bicycle ergometer procedure. At peak exercise left ventricular ejection fraction increased significantly (p < 0.05) only in overweight subjects. Exercise produced an increase of left ventricular ejection fraction in 14 overweight and in 5 moderately obese subjects and a decrease in 2 moderately obese subjects. At peak exercise mean heart rate and mean blood pressure increased significantly (p < 0.001) in both groups. When obese subjects were subgrouped according to duration of obesity, left ventricular ejection fraction increased significantly (p < 0.05) only in overweight subjects with duration of obesity less than 120 months. Duration of obesity correlated inversely with percent change in left ventricular ejection fraction (EF) at peak exercise (DELTAEF) (r = -0.59; p < 0.001). No correlation between body mass index and DELTAEF and between EF at rest and DELTAEF was observed. Our results suggest that higher degree and higher duration of obesity can impair left ventricular function response to exercise. In view of this, a noninvasive evaluation of left ventricular function could be useful to detect cardiac dysfunction early in subjects with higher degree and higher duration of obesity.