Hello.

I am performing optical mapping with Langendorff perfusion of rabbit heart.

During the experiment, some rabbits showed complete AV block (CAVB) just after starting Langendorff perfusion, and did not come back.

After the first case of CAVB, I tried to cannulate aorta at higher side.

Even after that, CAVB occurred again.

Sometimes CAVB improves after re-cannulation of aorta, but most of them does not.

As I wondered that there might be thrombus or air embolism, punctured the left coronary artery.

However, buffer solution rushed out of coronary artery, and no bubble went out, that means the coronary perfusion was good.

Also, staining with voltage dye and calcium dye were also good, that indicate the perfusion of coronary artery was good.

Do you guys have any other idea about the reason for which the Langendorff rabbit heart develop CAVB?

Is there possibility that grabbing heart (when harvesting heart) causes mechanical injury of AVN conduction?

Thank you for your advice!