Subclinical cardiac dysfunction and exercise performance in childhood cancer survivors.

BACKGROUND: Although anthracycline cardiotoxicity is clearly related to the cumulative dose administered, subclinical cardiac dysfunction has been reported across a wide range of treatment regimens, and its clinical significance is still unclear. Purpose of this study is to investigate by exercise echocardiography for subclinical cardiac dysfunction in survivors of pediatric cancer treated with low-moderate anthracycline doses, and to evaluate whether it may alter the response of the cardiovascular system to dynamic exercise. PROCEDURE: Post-exercise left ventricular end-systolic wall stress (ESS), left ventricular posterior wall dimension and percent thickening at end systole, and cardiopulmonary exercise test-derived indexes of cardiac function were examined in 55 apparently healthy patients (mean age 13.5 ± 2.9 years, median anthracycline cumulative dose 240 mg/m(2)) and in 63 controls. RESULTS: Subclinical cardiac dysfunction was identified in 17 patients (30%) presenting reduced left ventricular posterior wall dimension or percent thickening, or increased values of left ventricular ESS as compared to controls (group A), while the remaining patients formed group B. Reduced oxygen consumption at peak exercise in both groups of patients was the only cardiopulmonary exercise test variable resulting significantly different between patients and controls: no differences were found among the groups of patients. CONCLUSIONS: Our results confirm that even patients treated with a median anthracycline dose of 240 mg/m(2) (range 100-490) are at considerable risk of exhibiting subclinical cardiac dysfunction that, however, does not seem to alter the physiologic response of the cardiovascular system to dynamic exercise.

Aortic arch geometry and exercise-induced hypertension in aortic coarctation.

Hypertension at rest or during effort is not uncommon in patients with aortic coarctation (CoA), even those with a successful repair or mild degree of obstruction. Anatomic factors and functional abnormalities have been proposed as causes of this finding. Recently, aortic arch geometry was reported in association with hypertension at rest in patients with successful CoA repair. Forty-one patients (age 15.7 +/- 4.6 years) without significant obstruction at rest (mean systolic Doppler gradient at rest < or =25 mm Hg) were selected for the study. All patients underwent a maximal cardiopulmonary exercise test and magnetic resonance imaging of the aorta. Aortic arch shape was defined on global geometry as normal, gothic, and crenel. Percentage of anatomic narrowing (AN) was also calculated. Twenty-four patients (58%) showed exercise-induced hypertension (EIH). Regarding the shape of the aortic arch, normal geometry was present in 17 patients (41%), 9 (21%) had gothic geometry, and 15 (36%) had crenel geometry. There were no differences among the 3 geometries in regard to the incidence of EIH (70.6% in normal, 55.6% in gothic, and 46.7% in crenel) or AN (36.9% in normal, 33.5% in gothic, and 36.6% in crenel). In conclusion, our results fail to show a correlation between a specific aortic arch shape and the incidence of EIH and significant AN in patients with native or residual CoA or repeat CoA. Therefore, at present, the role of aortic arch geometry in identifying patients at risk of EIH is still uncertain.

Exercise-induced bronchodilation in natural and induced asthma: effects on ventilatory response and performance.

We studied whether bronchodilatation occurs with exercise during the late asthmatic reaction (LAR) to allergen (group 1, n = 13) or natural asthma (NA; group 2, n = 8) and whether this is sufficient to preserve maximum ventilation (VE(max)), oxygen consumption (VO(2 max)), and exercise performance (W(max)). In group 1, partial forced expiratory flow at 30% of resting forced vital capacity increased during exercise, both at control and LAR. W(max) was slightly reduced at LAR, whereas VE(max), tidal volume, breathing frequency, and VO(2 max) were preserved. Functional residual capacity and end-inspiratory lung volume were significantly larger at LAR than at control. In group 2, partial forced expiratory flow at 30% of resting forced vital capacity increased greatly with exercise during NA but did not attain control values after appropriate therapy. Compared with control, W(max) was slightly less during NA, whereas VO(2 max) and VE(max) were similar. Functional residual capacity, but not end-inspiratory lung volume at maximum load, was significantly greater than at control, whereas tidal volume decreased and breathing frequency increased. In conclusion, remarkable exercise bronchodilation occurs during either LAR or NA and allows VE(max) and VO(2 max) to be preserved with small changes in breathing pattern and a slight reduction in W(max).