Cardiovascular research
-
Cardiovascular research · Jan 2002
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of preconditioning (ischemic and pharmacological) on myocardial necrosis following coronary artery bypass graft surgery.
Ischemic preconditioning is known to protect the human heart from ischemic injury during coronary artery bypass graft (CABG) surgery but is not practised routinely. Adenosine A1 receptor agonists may confer protection in this setting by mimicking preconditioning. The aim of this study was to compare preconditioning, by ischemia or an adenosine A1 receptor agonist (GR79236X), with an established method of myocardial protection in CABG, namely intermittent cross-clamp fibrillation. ⋯ Ischemic preconditioning is superior to the other techniques at limiting myocardial necrosis during CABG. Pharmacological preconditioning may confer some benefit but this was not statistically shown using a specific adenosine A1 agonist (GR79236X).
-
Cardiovascular research · Jan 2002
Role of the 293b-sensitive, slowly activating delayed rectifier potassium current, i(Ks), in pacemaker activity of rabbit isolated sino-atrial node cells.
(i) to characterize the electrophysiological properties of the slowly activating delayed rectifier potassium current, i(Ks), defined as the 293b-sensitive current, during the action potential (AP) of rabbit sino-atrial node (SAN) pacemaker cells; (ii) to evaluate the contribution of i(Ks) to the pacemaker AP under physiological conditions and during beta-adrenergic stimulation. ⋯ Our findings suggest that in rabbit SAN: (i) i(Ks) is activated during the normal pacemaker AP; (ii) the contribution of i(Ks) to beating rate is small under control conditions; and (iii) i(Ks) contributes significantly to spontaneous pacemaker rate during beta-adrenergic stimulation.