Effects of aging and beta-adrenergic blockade on QT/QS2 changes induced by isometric exercise

L. De Caprio, M. Papa, D. Acanfora, F. Gallucci, M. Cicatiello, V. Canonico, F. Rengo

Research output: Contribution to journalArticlepeer-review

Abstract

Aging is known to cause changes in autonomic system function; in order to evaluate the ability of the electrical/electromechanical systole ratio in monitoring the effects of beta-adrenergic stimulation on the heart, the influences of aging and beta-blockade on ratio changes induced by isometric exercise (75% of maximal voluntary contraction) were studied. Study population was composed of 45 healthy volunteers (23 males and 22 females, aged 16 to 84) and was divided in three groups: group 1 (mean age 21 ± 3 years), group 2 (mean age 43 ± 10 years) and group 3 (mean age 74 ± 6). Ten subjects (mean age 35 ± 7) repeated the test after propranolol administration. Isometric exercise caused significant increase in heart rate, systolic and diastolic blood pressure in all 3 groups. Ratio values increased both in groups 1 and 2, but significantly only in group 1. No change in ratio was observed in group 3. Ratio changes induced by isometric exercise were significantly smaller in group 3 as compared to group 1 and correlated inversely with age. Propranolol administration prevented such ratio increase induced by isometric exercise. These data show that exercise-induced changes in the ratio are affected by aging, which causes a decrease in beta-receptorial sensitivity. However, the wide interindividual variability of the handgrip-induced ratio changes limits the utilization of this index as a parameter of sympathetic stimulation during this particular type of stress.

Original languageEnglish
Pages (from-to)101-109
Number of pages9
JournalJournal of Applied Cardiology
Volume3
Issue number2
Publication statusPublished - 1988

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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