Blind was diagnosed with heart muscle inflammation after suffering from dizziness in a Champions League game against Valencia in December.
The 29-year-old Dutchman was fitted with a subcutaneous implantable cardioverter defibrillator, which sends electrical pulses to regulate abnormal heart rhythms, and he made a surprise return to first-team training last week.
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"I am really happy to be back on the pitch," Blind, who came off the bench in the 77th minute, told Fox Sports Netherlands.
"I had a little bit of tension beforehand because you don't know how it will go.
"The doctor really needed to hold me back and step on the brakes because I wanted to get back ASAP. I wasn't scared at all, I wanted to get back on the pitch as fast as possible."
Blind will hope to continue his comeback in Ajax's next game against Eredivisie bottom side RKC Waalwijk on Sunday.
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