Recruitment of cardiac parasympathetic activity: effects of clonidine on cardiac vagal motoneurones, pressure lability, and cardiac baroreflex slope in rats

摘要

In the cardiology setting, an association between low para-nsympathetic drive to the heart (‘cardiac vagal activity’)nand poor outcome was demonstrated following myocardialninfarction.n1nTrauma or surgery is associated with lowncardiac vagal activity and low cardiac baroreflex sensi-ntivity.n2–4nA large beat-by-beat systolic blood pressuren(SBP) variability (‘pressure lability’) is associated withnpoor outcome following cardiac surgery;n56nbrisk changesnin pressure may increase shear stress, and plaque rupture,nleading to target-organ ischaemia. Low cardiac vagalnactivity and high pressure lability are associated.n47nAtnvariance with the accepted view of a link between high sympathetic activity and poor outcome, only logic, but nonevidence, suggests an association between low cardiacnvagal activity and poor outcome following trauma ornmajor surgery.