Background:
@EN cytosolic Ca2+ overload and oxygen derived free radicals may contribute to stunned myocardium. The present study was aimed to investigate the effects of nicardipine and sodium nitroprusside (SNP) on the functional recovery of postischemic
reperfused
myocardium.
@ES Methods:
@EN Fifty-seven halotane-anesthetized dogs were subjected to 15 minutes of left anterior descending coronary artery (LAD) occlusion and 2 hours of reperfusion. They were randomly assigned to receive either intracoronary nicardipine(n=11) or SNP
(n=10)
alone or both(nicardipine plus SNP, n=10). Eleven dogs that received saline i.c. served as the control. Regional myocardial contractility was evaluated by systolic shortening (%SS), the preload recruitable stroke work slope (Mw), and
intramyocardial
pressure (IMPs). Diastolic function was assessed by time constant of myocardial relaxation (IMP-tau)and postsystolic shortening(% PSS). LAD blood flow was measured by a Doppler flowmeter as well.
@ES Results:
@EN LAD occlusion produced a significant reduction in systolic as well diastolic functions to similar degrees in all groups. However, %SS was significantly higher in the nicardipine, SNP and nicardipine-SNP groups(67%, 56%, and 68% of baseline
values,
respectively) than in the controls(20%) at 3 hours of reperfusion. Furthermore. Mw recovered to the baseline with the onset of reperfusion in the three experimental groups. IMP-tau was restored to the baseline during early reperfusion in the
SNP-treated
groups but was significantly prolonged in the control and nicardipine groups throughout the reperfusion. LAD blood flow during reperfusion was higher in the SNP-treated groups in comparision to the control group.
@ES Conclusions:
@EN Treatment with either nicardipine or SNP enhances the recovery of regional contractile function in the canine model of myocardial stunning. SNP not nicardipine is also beneficial in attenuation of early diastolic dysfunction Nicardipine
combined
with SMP improved systolic as well as early diastolic functions more significantly when compared to either nicardipine or SNP alone. (Korean J Anesthesiol 1996; 30; 401~413)
|