title: Additive effects of age and silent myocardial ischemia on the left ventricular response to upright cycle exercise.
abstract: To separate the independent effects of age and silent myocardial ischemia on the left ventricular response to aerobic exercise, maximal upright cycle ergometry was performed in three groups: 8 clinically healthy older men [76 +/- 3 (SE) yr] with ischemic electrocardiogram (ECG) and Tl scan responses to prior maximal treadmill exercise (old silent ischemic subjects), 16 age-matched men with normal ECG and Tl scan responses (old controls), and 21 healthy young (33 +/- 1 yr) men (young controls). Although the left ventricular ejection fraction, end-diastolic volume index, and end-systolic volume index were similar in the three groups at rest, with increasing work loads there was a progressive increase in the end-diastolic volume index and a blunted decline in end-systolic volume index in the two older groups, which was most apparent in the old silent ischemic subjects. Thus, at peak effort, end-diastolic volume index was largest in old silent ischemic subjects (101 +/- 6 ml/m2), intermediate in old controls (85 +/- 6 ml/m2), and smallest in young controls (67 +/- 3 ml/m2) (P < 0.002); conversely, left ventricular ejection fraction was highest in young controls (85 +/- 2), intermediate in old controls (76 +/- 3), and lowest in the old silent ischemic group (66 +/- 2) (P < 0.001). At exhaustion the peak systolic pressure-end-systolic volume index was significantly lower in the silent ischemic group than in young controls (6 +/- 1 vs. 25 +/- 4 mmHg.ml-1 x m-2, respectively; P < 0.001) with the old controls in between (16 +/- 5 mmHg.ml-1 x m-2).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratory of Cardiovascular Science Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore 21224.
authors.forename: J L
authors.initials: JL
authors.lastname: Fleg
authors.forename: S P
authors.initials: SP
authors.lastname: Schulman
authors.forename: G
authors.initials: G
authors.lastname: Gerstenblith
authors.forename: L C
authors.initials: LC
authors.lastname: Becker
authors.forename: F C
authors.initials: FC
authors.lastname: O'Connor
authors.forename: E G
authors.initials: EG
authors.lastname: Lakatta
mesh_terms: D000328:Adult; D000332:Aerobiosis / Q000502:physiology; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001642:Bicycling; D001835:Body Weight / Q000502:physiology; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology*; D012146:Rest / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*