[Hemodynamic responses to supine bicycle exercise in juvenile hypertensive subjects: an echocardiographic assessment (author's transl)].
Six juvenile hypertensive patients were studied by supine bicycle ergometer exercise during continuous echocardiographic recording. Thirteen normotensive young men were also studied for the control. Left ventricular end-diastolic dimensions (Dd) during exercise was significantly increased from 28.8 +/- 0.5 mm/m2 to 29.7 +/- 0.6 mm/m2 in normotensives, but the increase in Dd was not observed in hypertensives. Effects of propranolol on changes in Dd during exercise were almost equal in two groups. Left ventricular end-systolic dimensions (Ds) were decreased during exercise in both groups. After propranolol administration, Ds in hypertensives was significantly increased from 18.8 +/- 1.0 mm/m2 to 19.4 +/- 1.1 mm/m2 at rest, and during the following exercise it reached to 19.7 +/- 1.1 mm/m2, whereas Ds in normotensives was decreased during exercise even after propranolol. Peripheral vascular resistance at rest was almost equal between the two groups, but in hypertensives the reduction during exercise was restricted. These results suggest that sympathetic activities of cardiovascular system are accentuated in juvenile hypertensive subjects.