Differential effects of propofol and sevoflurane on ischemia-induced ventricular arrhythmias and phosphorylated connexin 43 protein in rats.

BACKGROUND: The effects of anesthetics on ischemia-induced ventricular arrhythmias remain poorly studied. This study investigated the effects of propofol and sevoflurane on the survival rate and morbidity as a result of ventricular arrhythmias, and defined a possible mechanism for the arrhythmogenic properties of anesthetics during acute myocardial ischemia. METHODS: Under anesthesia with intraperitoneal sodium pentobarbital, Sprague-Dawley rats underwent 30 min of left anterior descending coronary artery ligation. The rats were divided into a low-dose propofol (Prop-LD) group (39 mg X kg(-1) X hr(-1), n = 18), a high-dose propofol group (78 mg x kg(-1) x hr(-1), n = 18), a sevoflurane group (2.5%, n = 18) and a control group (n = 18). The survival rate and morbidity as a result of ventricular arrhythmias were determined, and the amount of phosphorylated connexin 43 protein was measured 30 min after coronary artery ligation. RESULTS: The survival rate was 83% (15 of 18), 94% (17 of 18), 89% (16 of 18), and 67% (12 of 18, P = 0.038 vs. Prop-LD) in the control, Prop-LD, high-dose propofol, and sevoflurane groups, respectively. Sustained ventricular tachycardia was observed in 83% (15 of 18), 39% (7 of 18, P = 0.011 vs. control), 50% (9 of 18, P = 0.039 vs. control) and 94% (17 of 18, P < 0.01 vs. Prop-LD) in the control, Prop-LD, high-dose propofol, and sevoflurane groups, respectively. Immunoblotting showed a marked reduction in the amount of phosphorylated connexin 43 in the control and sevoflurane groups, as compared with the Prop-LD and high-dose propofol groups (P < 0.05). CONCLUSION: The authors' results suggest that propofol preserves connexin 43 phosphorylation during acute myocardial ischemia, as compared with sevoflurane, and this might protect the heart from serious ventricular arrhythmias during acute coronary occlusion.

Cardioprotective effects of propofol in isolated ischemia-reperfused guinea pig hearts: role of KATP channels and GSK-3beta.

PURPOSE: Propofol exerts cardioprotective effects, but the involved mechanisms remain obscure. The present study examines the cardioprotective effects of propofol and its role in cardiac function, including its effect on K(ATP) channel opening and the inhibition of GSK-3beta activity in ischemia-reperfused hearts. METHODS: Ischemia-reperfusion (I/R) was produced in isolated guinea pig hearts by stopping coronary perfusion for 25 min, followed by reperfusion. The hearts were incubated for ten minutes, with or without propofol (25 or 50 microM), or for five minutes with 500 microM 5-hydroxydecanoate (a mitochondrial K(ATP) channel blocker) or 30 microM HMR1098 (sarcolemmal K(ATP) channel blocker), followed by five minutes with 50 microM propofol before ischemia. Action potentials on the anterior epicardial surface of the ventricle were monitored using a high-resolution charge-coupled device camera system, and at five minutes after reperfusion, GSK-3beta phosphorylation at the serine residue, Ser9, was examined. RESULTS: After 35 min of reperfusion, propofol (25 and 50 microM) blunted the adverse effects of I/R and reduced infarct size (P < 0.05). In addition, prior incubation with 5-hydroxydecanoate or HMR1098 had no effect on functional recovery improved by 50 microM propofol. At five minutes after reperfusion, propofol (25 and 50 microM) shortened the duration of the action potential and increased the levels of phospho-GSK-3beta (P < 0.05). CONCLUSIONS: Propofol enhanced mechanical cardiac recovery and reduced infarct size. The data further suggest that GSK-3beta play an important role in propofol cardioprotective actions during coronary reperfusion, but mitochondrial K(ATP) channels do not.

Cardioprotective effect and mechanism of action of landiolol on the ischemic reperfused heart.

PURPOSE: The authors examined the cardioprotective effect of landiolol, an ultra short-acting, highly selective beta1-blocker, and its role in cardiac work, antioxidative effect, and sarcoplasmic reticulum (SR) function in hearts subjected to ischemia-reperfusion. METHODS: Isolated guinea pig hearts were subjected to ischemia-reperfusion by stopping the perfusion for 45 min and reperfusing. Before the ischemia, hearts were treated with landiolol (20, 100, or 500 microM) for 15 min (LAN group). In another set of experiments, before ischemia, hearts were washed out for 15 min after treatment with landiolol (WO group). In other hearts, the tissue concentration of malondialdehyde was measured after reperfusion. We also examined the phosphorylation of phospholamban at Ser(16) and Thr(17)residues to evaluate the SR function. RESULTS: After 90 min of reperfusion, left ventricular pressure (LVP) was restored significantly in the LAN-500 microM group regardless of heart rate. However, the improvement in recovery in LVP disappeared in the WO group. The tissue malondialdehyde levels were decreased in the LAN group compared with those in the control group. In the control group, the phosphorylation of phospholamban at Ser(16) and Thr(17) residues was markedly increased after reperfusion. Landiolol at 500 microM suppressed the increase of phosphorylation at Ser(16) residues. CONCLUSION: The present study demonstrated that landiolol had a lipid peroxidation-reducing effect and suppressed the increase in phospholamban phosphorylation at the Ser(16) residue in hearts subjected to ischemia-reperfusion. These findings indicate that landiolol may have an anti-ischemic effect, via an antioxidant effect and/or via preserving SR function during the ischemic period.

[Perioperative complications of patients with cementless femoral head replacement].

BACKGROUND: Studies have shown that use of cement is a risk factor for fat embolism in elderly patients with femoral neck fracture. We investigated the usefulness of the cementless femoral head replacement technique. METHODS: A retrospective study of 58 patients who had undergone this technique between January 1995 and May 2001 was conducted. Perioperative complications, hospital length of stay, activities of daily living, and postoperative mortality were studied. RESULTS: Of 58 patients, 42 (72.4%) were fe- males, and the mean age was 75.4 years. Twenty patients (69.0%) were classified as ASA class 2, and 50 patients (86.2%) had preoperative medical complications. Cardiovascular complications were the most prevalent, and 6 patients (10.3%) had serious perioperative complications, and postoperative death was noted in 1 patient within one month (1.7%), and 4 patients (6.9%) within one year. Average length of hospital stay was 64.2 days and activities of daily living were the same level as before the fracture. CONCLUSIONS: Early rehabilitation was possible and hospital length of stay and activities of daily living were not inferior to the other treatments. We believe that cementless femoral head replacement technique was useful for elderly patients.