If it were my body i would definately make an appt. with my heart doc. You say that you have had a couple of tach episodes that is sending your heart into the 200 plus range and that is not good. I do not know if you are on medications or take an aspirin a day but i would not take chances with this and try to pass it off from a wood burning stove. The doc can definately give you a little something like a beta blocker to help manage the tach and i am sure will be telling you to take an aspirin a day to protect you from tossing a clot during the episodes. Tach is usually electrical based however there are alot of things that could set it off...like Jerry said in his post it can be a cause and effect sort of thing...don't take chances...call the doc it is a pretty simple resolution in most cases and we only get one shot at life....good luck
You may have a Vitamin D deficiency this time of the year due to the lack of sun shine on your skin. This lack of sun shine my also case depression problems. All of these can cause heart rhythm problems.
If the wood stove is "properly" ventilated I don't see any reason for it to cause problem. Are you a serious wood heat family? That is, do you heat with wood 24/7 ? If yes, you may want to explore that subject further, perhaps on a wood heat forum/blog.