ABOVE-NORMAL LEFT-VENTRICULAR SYSTOLIC PERFORMANCE DURING EXERCISE INYOUNG SUBJECTS WITH MILD HYPERTENSION

Debate continues on whether left ventricular (LV) systolic function du ring exercise is abnormal in young subjects with mild hypertension and on whether the abnormal blood pressure (BP) trend observed in hyperte nsives during prolonged exercise is due to impaired LV function. LV fu nction was measured by means of M-mode echocardiography during prolong ed exercise in 13 physically trained, young, mild hypertensives and 12 age-matched, trained normotensives with similar working capacity. Sys tolic BP/end-systolic volume (SBP/ESV) and end-systolic stress/ESV at rest were greater in the hypertensives (P<0.0001 and P = 0.034), while LV filling was impaired (P = 0.05). BP changes during the first 20 mi n of exercise were similar in the two groups, but thereafter the betwe en-group BP difference tended to decline progressively. LV diastolic d imension was similar at rest. During exercise it slightly increased in the normotensives and slightly decreased in the hypertensives (P = 0. 032). Exercise ejection fraction (P = 0.018), SBP/ESV (P < 0.0001) and stress/ESV (P = 0.027) were greater in the hypertensives throughout t he test. SBP/ESV normalized for LV wall thickness (P<0.0001) and the c hanges in SBP/ESV from rest to exercise were also greater in the hyper tensives (P = 0.002). Stroke volume increased to a lower extent in the hypertensives, but the between-group difference was not statistically significant. The increase in SBP/ESV from rest to exercise was relate d to the concentric remodelling of the ventricle in the hypertensives (P<0.0001) and the subjects grouped together (P<0.0001), but not in th e normotensives. In conclusion, increased LV systolic performance is p resent early in hypertension not only at rest but also during vigorous exercise. It is partly due to concentric remodelling of the left vent ricle and partly to enhanced inotropic state.