Figure 5. Effect of KATP channel inhibition (1 μm TOLB) on APD and CFR during gradual perfusate deoxygenation in LANG hearts when pacing at 330 ms CL.
A, TOLB blunts APD shortening during perfusate deoxygenation in LANG hearts. With TOLB, APD remained relatively constant until 40% oxygenation, after which APD dramatically shortened. Without TOLB, APD gradually shortened with deoxygenation until 30% oxygenation, after which APD dramatically shortened. B, with TOLB, APD was significantly longer at 100% and 50% perfusate oxygenation. C, coronary flow of LANG hearts with TOLB has higher during perfusate deoxygenation and increased to a greater extent than the coronary flow of LANG hearts without TOLB. Values are the mean ± SE; LANG, n = 7; LANG + TOLB, n = 4. *Significant difference in APD between LANG hearts with and without TOLB.