Key result
Ischemic preconditioning significantly reduced right ventricular myocardial infarct size compared to control (24.4% vs. 42.6%, p < 0.0001) in isolated rat hearts.
Why the study?
Does ischemic preconditioning reduce right ventricular infarct size in isolated rat hearts?
RCT (n=39)
randomized
Does ischemic preconditioning reduce right ventricular infarct size in isolated rat hearts?
Absolute Event Rate: 24.4% vs 42.6%
p-value: p=< 0.0001
Ischemic preconditioning reduces right ventricular infarct size and improves contractile function in isolated rat hearts, likely via mitochondrial K(ATP) channel opening.
Extends ischemic preconditioning to right ventricular protection in preclinical models; hypothesis-generating and should not change practice.
OBJECTIVES: We investigated whether ischemic preconditioning (IPC) protects the right ventricular (RV) myocardium against ischemic injury in hearts treated with the specific mitochondrial ATP-sensitive potassium (K(ATP)) channel blocker 5-hydroxydecanoate (5-HD). METHODS: Hearts from male Wistar rats (300 g, n = 39) were isolated and perfused with Krebs-Henseleit buffer and randomized to no IPC (control, n = 16), IPC (n = 16) or IPC preceded by addition of 5-HD (100 µM, n = 7). IPC consisted of 2 × 5 min of global ischemia followed by 40 min of global ischemia and 120 min of reperfusion. The effect of IPC on RV myocardial infarct size was evaluated by measurement of the infarct size/area-at-risk ratio (RVIS/AAR). Postischemic RV function was evaluated by RV pressures. RESULTS: IPC produced a marked decrease in RVIS/AAR (24.4 ± 8.1 vs. 42.6 ± 10.6%, p < 0.0001) and improved hemodynamic recovery of RV contractile function compared with the control group. We found no difference in RVIS/AAR (45.2 ± 4.4 vs. 42.6 ± 10.6, p > 0.05) or hemodynamic recovery between IPC + 5-HD and control hearts. Blockade of mitochondrial K(ATP) channels by 5-HD abolished the cardioprotective response to IPC. CONCLUSION: IPC reduces RV myocardial infarct size and improves postischemic RV contractile function in the isolated rat heart, possibly through opening of the mitochondrial K(ATP) channel.
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Andersen et al. (2012) conducted an RCT in Ischemic injury (n=39). Ischemic preconditioning (IPC) vs. No IPC (control) was evaluated on Right ventricular myocardial infarct size (RVIS/AAR) (p=< 0.0001). Ischemic preconditioning significantly reduced right ventricular myocardial infarct size compared to control (24.4% vs. 42.6%, p < 0.0001) in isolated rat hearts.
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