Problemns with isolation of cardiomyocytes from adult mouse

[krit26]

I'm working with isolation of cardiomyocytes from adult mouse for my studies on ischemia-reperfusion injury.

My problem is that I'm not able to get a good yield of cardiomyocytes. Most of them (80%) are round shaped. I think they are getting round shaped because of spontaneous contraction, but I'm adding BDM (contraction inhibitor). I'm not adding any calcium in the perfusion buffer and very little on digestion buffer. Then I increase the calcium by using buffers to stop the digestion and sequentially increase calcium concentration as well.

I'm not sure what to do to stop them from getting rounded up. If somebody can help me get a good yield of cardiac myocytes, I'll be very thankful.