Non-invasive evaluation of autonomic tone changes during isometric exercise in normal subjects and in patients with coronary artery disease

Lorenzo De Caprio, Carlo Vigorito, Domenico Acanfora, Domenico Artiaco, Luigi Ascione, Marco Papa, Franco Rengo

Research output: Contribution to journalArticlepeer-review

Abstract

In order to evaluate the clinical implications of QT/QS2 ratio during manoeuvres of sympathetic stimulation we studied the effects of handgrip (75% of maximal voluntary contraction) in 18 middle-aged normal subjects and in 16 patients with previous myocardial infarction. We also evaluated the effects of propranolol (0.1 mg/kg i.v.) in all normal subjects and in 10 of the 16 patients with coronary artery disease. At rest the two groups had similar heart rate, blood pressure, QT, QS2 and QT/QS2 ratio values. A significant increase in heart rate and systolic blood pressure was recorded during handgrip both in normal subjects and in patients with coronary artery disease; QT/QS2 significantly increased in normal subjects but did not show significant variations in patients with coronary artery disease, with significant differences between the two groups at peak exercise. Handgrip-induced QT/QS2 changes showed a marked variability both in normal and diseased subjects. After propranolol, QT/QS2 showed no significant difference at peak exercise in the two groups. The variability of ratio changes was nullified by the administration of the drug. These findings suggest that handgrip-induced QT/QS2 changes might be an expression of beta-adrenergic discharge. The clinical value of handgrip-induced QT/QS2 changes in detecting patients with coronary artery disease is limited by the variability of the response of the ratio observed in the two groups.

Original languageEnglish
Pages (from-to)171-183
Number of pages13
JournalInternational Journal of Cardiology
Volume13
Issue number2
DOIs
Publication statusPublished - 1986

Keywords

  • Coronary artery disease
  • Handgrip
  • QT/QS2
  • β-Blockade

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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