When is the soonest a heartbeat can be detected during a ultrasound? can a heartbeat be detected 22 days after conception?

Very rarely: The soonest a heartbeat can be reliably detected is at 6 weeks ega, so that would be 28 days after a certain conception. Very occasionally, a heartbeat can be seen in the 5th week (22-27 days), but it's really unusual and you shouldn't count on it.

Maybe: The heartbeat can be detected in 80% of patients at five weeks based on the first day of the last menstrual period. Assuming you ovulated on the 15th day, you would be at that five-week date about now.