The risk of AF is significantly higher in athletes compared with not athletes. However, this finding should be confirmed further in large-scale prospective longitudinal studies.

No abstract

In two experiments maximal aerobic power (VO2max) calculated from maximal mechanical power (Wmax) was evaluated in 39 children aged 9-11 years. A maximal multi-stage cycle ergometer exercise test was used with an increase in work load every 3 min. In the first experiment oxygen consumption was measured in 18 children during each of the prescribed work loads and a correction factor was calculated to estimate VO2max using the equation VO2max = 12.Wmax + 5.weight. An appropriate increase in work rate based on height was determined for boys (0.16 W.cm-1) and girls (0.15 W.cm-1) respectively. In the second experiment 21 children performed a maximal cycle ergometer exercise test twice. In addition to the procedure in the first experiment a similar exercise test was performed, but without measurement of oxygen uptake. Calculated VO2max correlated significantly (p less than 0.01) with those values measured in both boys (r = 0.90) and girls (r = 0.95) respectively, and the standard error of estimation for VO2max (calculated) on VO2max (measured) was less than 3.2%. Two expressions of relative work load (%VO2max and %Wmax) were established and found to be closely correlated. The relative work load in %VO2max could be predicted from the relative work load in %Wmax with an average standard error of 3.8%. The data demonstrate that calculated VO2max based on a maximal multi-stage exercise test provides an accurate and valid estimate of VO2max.

Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide ventriculography (RNV) and contrast ventriculography measurements of LVEF for comparison. ECHO-LVEF from the 41 patients correlated well with the reference methods (y = 1.5x – 14.7, r = 0.93; linear regression analysis; 95 % confidence limit for a single determination of ECHO-LVEF was 17.2). Interobserver variability by linear regression was r = 0.89, SEE = 7.1 with a mean difference between paired observations of-1.5 ± 6.9 (SD). In a random sample of 18 patients (45 observations), ECHO-LVEF allowed separation between RNV-LVEF values ≧ 40 and < 40, representing low and high risk groups following AMI. Thus, the results showed that simple, readily available wall motion-derived estimates of LVEF were as closely associated with LVEF measured by standard reference methods as were previously published, more cumbersome, plani-metric echocardiographic methods. Reporting on global LVEF function in LVEF units rather than in nonstandardized wall motion scores of index values may facilitate intra- and interhospital communication and the use of optimized echocardiographic risk stratification after AMI.

Cardiovascular and muscle load levels were evaluated during floor cleaning. A group of 12 experienced female cleaners participated in the study. Of the subjects 6 used a mopping method and 6 a traditional scrub and cloth method. Heart rate, oxygen consumption, rating of perceived exertion, electromyography from the trapezius muscle and video recordings were obtained during floor cleaning. With respect to relative heart rate and oxygen consumption the two groups did not differ. The results revealed a high cardiovascular load corresponding on average to 53 percent of the individual maximal oxygen uptake. In addition 65 percent of the observed period was spent with the back in a position forward flexed more than 20 degrees C. The time spent in extreme forward back flexion was shorter for the mopping group. Both groups exhibited high static, median and peak shoulder muscle load levels of 10 percent, 25 percent and 54 percent maximal voluntary contraction, respectively. At the same time, however, the mopping group tended to have a higher shoulder load than the group using the scrub and cloth method. Furthermore, electromyographic signs of fatigue in the trapezius muscle indicated a more stereotype activation of the shoulder muscles during mopping than during scrubbing. Based on these results, it was concluded that mopping cannot be recommended as less strenuous than scrubbing.