Cardiodynamics and infarct size in regional and global ischemic isolated heart model: comparison of 1 hour and 2 hours reperfusion

Abstract

Background and objectives: We investigated whether 1 hour reperfusion is enough to assess cardiodynamics and infarct size in both regional ischemia (RI) and global ischemia (GI) in isolated rat heart models.

Materials and methods: Hearts were randomly assigned to one of the following groups (each n=14): 1) Sham hearts for 1 hour; 2) Sham hearts for 2 hours; 3) 30 minutes RI followed by 1 hour reperfusion; 4) 30 minutes of RI followed by 2 hours reperfusion; 5) 30 minutes GI followed by 1 hour reperfusion; and 6) 30 minutes GI followed by 2 hours reperfusion.

Results: There were no significant differences in infarct size between 1 hour and 2 hours reperfusion in both RI and GI. Left ventricular developed pressure was significantly decreased at both 1 hour and 2 hours reperfusion in groups of RI and GI compared to baseline (p<0.01). Rate-pressure product and +dP/dt(max) also significantly decreased compared to baseline level at both 1 hour and 2 hours reperfusion in groups of RI and GI (p<0.05).

Conclusion: There was no significant difference in infarct size between 1 hour and 2 hours reperfusion in groups of RI and GI. Cardiodynamic variables measured at 1 hour and 2 hours reperfusion significantly decreased compared to baseline level. Our data suggests that reperfusion of 1 hour is sufficient to assess cardiodynamics in both regional and global ischemic isolated hearts model.

Keywords: Heart; Myocardial infarction; Myocardial ischemia; Myocardial reperfusion.

Fig. 1

Experimental protocols. For measurement of infarct size and cardiodynamics, isolated rat hearts were exposed to 30 minutes ischemia followed by 2 hours reperfusion. Details for S1, S2, R1, R2, G1, and G2 are provided in the text.

Fig. 2

Morphometric changes after myocardial ischemia and reperfusion in isolated rat heart. A: representative sequential left ventricle slices each group showing area of necrosis (pale area) with triphenyltetrazolium chloride staining. B: percent of infarct area over area at risk. Values are mean±SEM. Details for S1, S2, R1, R2, G1, and G2 are provided in the text. There were no significant differences in AN/LV and AN/AR between S1 and S2, R1 and R2, and G1 and G2, respectively. AR: area at risk, AN: area of necrosis, LV: left ventricle, SEM: standard error of mean.

Fig. 3

Changes in coronary flow in isolated rat hearts. 1 hour and 2 hours means 1 hour and 2 hours after reperfusion, respectively. ^*p<0.05 vs. baseline, ^†p<0.05 vs. 1 hour after reperfusion.

Fig. 4

Changes in cardiodynamics in isolated rat hearts. 1 hour and 2 hours means 1 hour and 2 hours after reperfusion, respectively. ^*p<0.05 vs. baseline, ^†p<0.05 vs. 1 hour after reperfusion.