Global versus regional myocardial ischaemia: Differences in cardiovascular and sympathetic responses in cats

Federico Lombardi, Carlo Casalone, Gabriella Malfatto, Massimo Pagani, Alberto Malliani

Research output: Contribution to journalArticle

Abstract

Summary: The cardiovascular and sympathetic responses to occlusions of the left main ("global" ischaemia) or distal left anterior descending ("regional" ischaemia) coronary artery were studied in 19 anaesthetised cats with chronic sinoaortic baroreceptor denervation. "Global" ischaemia, before vagotomy, resulted in a significant reduction of mean arterial pressure (MAP), left ventricular pressure (LVP), and LVdP/dtmax while sympathetic efferent impulse activity was significantly augmented during the initial 15±2 s of occlusion (early phase) and, vice versa inhibited during the subsequent 20±2 s of occlusion (late phase). Vagotomy did not modify the haemodynamic responses, however, a significant increase in sympathetic discharge was detectable during the whole occlusion period (early and late phases). "Regional" ischaemia, before vagotomy, resulted in a significant increase in sympathetic neural discharge and MAP, with no changes in left ventricular function. After vagotomy the occlusion elicited a significant increase in MAP, LVP, LVdP/dtmax and efferent sympathetic neural activity. These excitatory responses were abolished after the interruption of a large part of the cardiac sympathetic afferents. Thus coronary artery occlusion induced haemodynamic and sympathetic reflex responses that were dependent upon the interaction of opposite influences mediated by the simultaneous activation of cardiac vagal and sympathetic afferents. The extent of "ischaemic myocardium" represented a determinant factor for the prevailing type of neural response.

Original languageEnglish
Pages (from-to)14-23
Number of pages10
JournalCardiovascular Research
Volume18
Issue number1
DOIs
Publication statusPublished - Jan 1984

Keywords

  • Cardiac innervation
  • Coronary occlusion
  • Myocardial ischaemia
  • Sympathetic afferent fibres
  • Sympathetic reflexes
  • Vagal afferent fibres

ASJC Scopus subject areas

  • Statistics, Probability and Uncertainty
  • Applied Mathematics
  • Physiology (medical)
  • Physiology
  • Cardiology and Cardiovascular Medicine

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