Additive effects of age and silent myocardial ischemia on the left ventricular response to upright cycle exercise

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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 TI scan responses to prior maximal treadmill exercise (old silent ischemic subjects), 16 age- matched men with normal ECG and TI 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 · m-2, respectively; P < 0.001) with the old controls in between (16 ± 5 mmHg · ml-1 · m-2). Thus the diminished aerobic capacity, cardiac dilatation, and blunted ejection fraction response to upright cycle ergometry associated with normative aging are exaggerated in asymptomatic older men with exercise- induced silent myocardial ischemia.

Original languageEnglish (US)
Pages (from-to)499-504
Number of pages6
JournalJournal of applied physiology
Volume75
Issue number2
DOIs
StatePublished - 1993

Keywords

  • left ventricle
  • silent ischemia

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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