Graded exercise testing in hypertensive and normotensive subjects: a hemodynamic and electrocardiographic comparison

The purpose of this study was to determine if R-wave amplitude (Ramp) changes during a graded exercise test (GXT) would differentiate between middle-aged subjects with hypertension (HT) and normotension. Fifteen subjects with HT, 11 trained subjects with normotension (TR), and nine untrained subjects with normotension (UT) underwent a maximal GXT using the Bruce protocol. HT subjects exhibited higher systolic and diastolic blood pressure at rest and each stage of the GXT (P<.05). Rate-pressure product (RPP) was greater at every level (P<.05), except rest and stage 1, in those HT subjects not on beta blockade (HT-NBB; n = 9) compared with those on beta blockade (HT-BB; n = 6). RPP in HT-NBB subjects was greater than in both TR and UT subjects at every level (P<.05). TR subjects exhibited a larger Ramp at rest (x̄ = 20.2 mm) than HT (x̄ = 12.7 mm) and UT subjects (x̄ = 10.6 mm), however, an analysis of covariance (ANCOVA) found all three groups to exhibit a similar Ramp response during exercise (P>.05). Values for TR, HT, and UT subjects at peak exercise decreased to 17.1 mm, 11.5 mm, respectively. Ramp also failed to distinguish between HT subjects meeting ECG criteria for left ventricular hypertrophy (ECG-LVH) (n = 5) and HT subjects without ECG-LVH (n = 10). Comparisons between HT subjects with ECG-LVH and TR subjects with ECT-LVH (n = 8) also revealed no differences in Ramp response. In addition, Ramp response in HT-BB subjects did not differ from HT-NBB subjects or the other groups (P<.05). The results of this study do not support the hypothesis that exercise-induced Ramp changes are sensitive indicators of ventricular function. Exercise-induced Ramp changes do not appear helpful in distinguishing subjects with HT from subjects with normotension. In addition, previous findings of Ramp increases during maximal exercise in subjects on beta blockade were not substantiated.