Ergometric performance and cardiovascular profile of obesity clinic patients.

BACKGROUND: Aerobic exercise capacity is considered as an independent prognostic factor for cardiovascular disease and mortality. It is usually expressed in maximal oxygen consumption (VO2(max)) or metabolic equivalent (MET) and is measured by spiroergometry or calculated by a regression formula based on maximal performance achieved. Obesity is associated with reduced physical performance and increased cardiovascular mortality. The aim of our study was to describe the ergometric and cardiovascular profile of patients of an obesity clinic, and to compare a direct measure of VO2(max) with an indirect by a regression formula and to. METHOD: 131 consecutive patients of an obesity clinic (95 females, 36 males) aged 16-75 years participated. The VO2(max) was measured by spiro-ergometry on a treadmill and estimated by a regression formula on the basis of the speed and grade of the treadmill. We have determined the relationship between Body mass index (BMI), Waist Circumference (WC) and the parameters VO2(max)/kg, MET, Performance Relative for Age, Heart Rate Recovery one minute after maximal effort (HRR), VO2(max) relative to a theoretical normal body weight (corresponding to a BMI of 25 kg/m2 (VO2(max)Rel25)), blood pressure, at rest and 5 minutes after exercise, Framingham Score and C-reactive protein (CRP). RESULTS: For the different age groups the VO2(max)/kg was below normal values (mean -23.4%). Measured VO2(max) was 15.2% lower than estimated by the regression formula. After adjusting to age and to a theoretical upper-limit normal body weight (corresponding to a BMI of 25 kg/m2) VO2(max)/kg was 5-20% (mean value 15%) higher than the reference values. VO2(max)/kg and HRR were correlated with BMI, WC and Framingham Score. 40% of the patients were already treated for hypertension, 55% had elevated blood pressure measurements at rest and 52% after exercise. CONCLUSIONS: Ergometric stress testing in obese subjects delivers important information that helps to evaluate the cardiovascular risk in this population and to provide individual recommendations for training therapy (e.g. training intensity, heart rate etc). Obese patients show a marked diminution of aerobic exercise capacity. In this population, the use of a standard regression formula to calculate VO2(max) leads to an overestimation of aerobic performance. The even higher than normal VO2(max) related to upper-normal body weight indicates that the reduced physical performance in obese patients is rather due to the overweight than to a pathological loss of muscle mass.

Echocardiography of the right ventricle in athlete's heart and hearts of normal size compared to magnetic resonance imaging: which measurements should be applied in athletes?

Right ventricular (RV) pathologic hypertrophy and cardiomyopathy have been reported to be related to ventricular arrhythmias and sudden cardiac death in athletes. However, it is unclear which echocardiographic measurements reflect RV dimensions in athlete's heart (AH) correctly. We aimed to compare two-dimensional echocardiography of the RV in AH and normal hearts to magnetic resonance imaging (MRI), and derive recommendations for RV echocardiography in athletes. Twenty-three healthy male endurance athletes with AH (A; 28+/-4 yrs) and 26 healthy untrained males (C; 26+/-4 yrs) matched for body-dimensions were examined. In recommended echocardiographic parasternal and 4-chamber views, three enddiastolic RV free wall-thicknesses (T1,T5,T9) and RV diameters were determined (M-mode enddiastolic diameter [RV-EDD]; longitudinal [RV-LAX], sagittal, outflow-tract and tricuspid valve anulus diameters). MRI determined RV enddiastolic volumes (RV-EDV) and masses (RVM) in A and C were: 162+/-29 vs. 136+/-15 ml and 76+/-10 vs. 59+/-13 g (p<0.001). Significant correlations between RV-EDV and RV-EDD (r=0.49; p=0.001) as well as RV-LAX (r=0.38; p=0.01), and RVM and T5 (r=0.52; p=0.01) were found. For RV echocardiography, significant differences between A and C were documented for RV-EDD (medians [quartiles]: A: 26 mm [24/29 mm]; C: 22 mm [21/27 mm]; p=0.04; measurable in 49/49 subjects), and in the parasternal short axis view for T5 (A: 6.0 mm [5.4/7.8 mm]; C: 5.0 mm [4.5/5.2 mm]; p=0.04; measurable in 22/49). In conclusion, two-dimensional echocardiographic RV measurements offer only a limited potential to reflect true RV dimensions. Only RV-EDD may differentiate between normal hearts and exercise related RV adaptations in AH, and is the only recommendable parameter to be measured in athletes routinely. In unclear cases additional methods should be used to examine the RV in athletes.

Effect of X-ray contrast media on blood flow properties after coronary angiography.

In vitro studies suggest that ionic and nonionic X-ray contrast media have different effects on rheological parameters. The risk of thrombotic complications in coronary interventions was reported to be lower using ionic contrast media. The aim of the present study was to compare the effects of different types of contrast media on rheological parameters after coronary angiography. Sixty patients were randomized to four groups: ioxaglate 320 (dimeric, ionic, n = 18), iomeprol 400 (monomeric, nonionic, n = 12), iobitridol 350 (monomeric, nonionic, n = 12), and iodixanol 320 (dimeric, nonionic, n = 18). Blood samples were collected via the side port of the arterial sheath immediately before and at the end of coronary angiography. In our study, all types of contrast media caused a significant decrease in haematocrit (Hct), plasma viscosity (PV), erythrocyte aggregation (EA), and in the platelet reactivity index (PRI). The most pronounced decrease in Hct was found using the ionic dimer ioxaglate. There were no significant differences between the contrast media with respect to their effects on PV, EA, and PRI.