I had catheter ablation last year for SVT avnrt. Now I am 9weeks pregnant and have irregular heartbeats again. My heart pauses for 10 sec before the next beat. I can't breath. Is it svt? What do I do?

Revisit the issue. Please let the electrophysiologist performed the procedure know this without delays... In addition, keep your ob/gyn informed of this as well... Wishing you the best luck!
See Doc. It is impossible to know for sure what your irregular heart beat without testing, which will likely include an ekg, or a home monitor (holter or event recorder) to determine what it is you have and if any treatment is needed.
Arrhythmia . It doen't sound like svt, it may however be related to pregnancy and the ablation. See your doctors for evaluation.