Hi
This is what hapened to my friend who may have had different severity and circumstances to your own and in no way means it will happen to you, but she was advised to have an epidural as if SVT occurs during labour very hard to stop (pain can make it worse) and strongly advised to have a Csection. She ended up opting for the section as had a few runs of SVT in the month before she delivered and got scared which is understandable. If you have a cardiologist I would speak to them about the risks as everyone is slightly different and a cardiologist may have a different perspective than your ob.