Keep in mind that heart valves are pathways that give doctors access to test points where they can establish measurements. Valves may be checked after the procedure via echocardiography or other methods. A murmur is just a sound. How do you feel? I had a doctor tell me once that a powerful heart can create a murmur because it gives an extra swish as the blood passes through the valve. Could also be an indication of some other type of change, good or bad. Ask your doc.
I would definitely question your doctor about this. You deserve an explanation. I know very little about murmurs but the only other possible thing I can think it might be, and I could be totally way off base with this, is a transeptal puncture? Did they need to do one to accomplish your ablation? If so maybe the sound is coming from that and not from a murmur. I have no idea if that would cause a sound or not but you deserve to understand your murmur in the minimum so give them a call and see what they say.