Had heart cath 6days ago through groin. bruised & knot where procedure occurred and 2&1/2 inches down from that area. normal?

Might be: How big a lump? If its bigger than a golf ball or continues to throb or get bigger it should be checked by a medical professional. Bruising is not unusual but it should be soft and non-tender.

Post CATH: Some bleeding into the groin is not unusual post femoral puncture. It often dissects lower also. This should not in general be pulsatile or painful. It is worth having your dr. Check it.