recording technique
8.In control group, combined with the programmed electrical stimulation technique,formaldehyde used as sinuatrial node blocker was injected into the node directly,and then the MAPD100 of subendocardium(Endo), midmyocardium(Mid), subepicardium(Epi) and TDR were recorded with the monophasic action potential recording technique when CC was equal to 300 ms、500 ms、700 ms and 900 ms, respectively.

