Abstract
OBJECTIVE: To investigate the effect of sevoflurane on the monophasic action potentials (MAPs) in isolated rat hearts after ischemia-reperfusion. METHODS: Twenty-four healthy SD male rats, weighing 280-320 g, were randomly divided into three groups after successful preparation of a Langendorff isolated heart perfusion model with a stabilization period perfusion of 15 min with Krebs-Henseleit (K-H) fluid (n = 8): the control group (group A, continuously perfused with K-H fluid for 105 min), the ischemia-reperfusion group (group B, continuously perfused with K-H fluid for 15 min, and then exposed to 60 min of global ischemia induced by Thomas solution followed by 30 min of reperfusion), and the sevoflurane group (group C, K-H fluid contained 1.0 MAC sevoflurane, and other procedures were same as in group B). Heart rate (HR) and MAPs including time course (MAPD(50) or MAPD(90)) of the epicardium (Epi) and endocardium (Endo) were recorded at the time of balance perfusion for 15 min (T (0)), continuous perfusion for 15 min (T (1)), reperfusion for 15 min/continuous perfusion for 105 min (T (2)), and reperfusion for 30 min/continuous perfusion for 120 min (T (3)), and the transmural dispersion of repolarization (TDR) was calculated. The incidence of arrhythmia, time for restoration of spontaneous heart beat, and duration of arrhythmia were recorded during the period of reperfusion. RESULTS: HR in group B and group C was lower at T (2) and T (3) than that in group A, while that in group B was significantly lower than that in group A at T (2) and T (3), and HR in group C was higher than that in group B at T (2) and T (3) (P < 0.05). There was no difference of TDR in each group at T (0) and T (1) (P > 0.05), while TDR in group B was increased at T (2) and T (3) compared with that in group C and group A (P < 0.05). TDR in group C was decreased compared with that in group B at T (2) and T (3) (P < 0.05), while there was no such difference between group C and group A (P > 0.05). The time for restoration of spontaneous heart beat and duration of arrhythmia in group C were shorter than those in group B (P < 0.05), while cardiac arrhythmia scores in group B were higher than those in group C (P < 0.05). There was no difference of MAPD(50) in each group (P > 0.05). The MAPD(90) in group B was much longer than that in other groups at T (2) and T (3) (P < 0.05), while there was no such difference between group C and group A (P > 0.05). The prolonged MAPD(90) at T (2) and T (3) in group B strikingly differed from that at T (0) and T (1) (P < 0.05). Nevertheless, there was no such difference in other groups at different time points (P > 0.05). CONCLUSION: Sevoflurane alleviates reperfusion arrhythmia induced by myocardial ischemia-reperfusion through the shortening of MPAD(90) in isolated rat hearts.