I would continue to take the tenormin which has worked well for you in the past. Also you should have an objective measurement of your ejection fraction as some chemotherapeutic agents can cause a dilated cardiomyopathy. I can't really comment on helping you see someone out of your insurance network.
No real comment on your issues per se, but am glad to hear that your chemo is over and you are on the road to recovery. The issue with insurance coverage is troublesome. I would guess your best bet is to speak with the office manager directly and send a letter to the Dr him/herself, explaining that you need help to continue seeing him/her. If you have out of network coverage, then it will cost you a bit more out of pocket but may be worth the money, depending on the number of visits. If you have no out of network coverage, then you may try having asking the office help you - either by negotiating a price with the office, or with an appeal for coverage based on his specialised knowledge of your health issues. Your insurance company customer service should be able to help explain to you, how to do this. Some insurance companies are also now offering essentially a "case manager" for complex cases and "high users" of services. I suspect you would qualify for this, its a cost free service and they are there to help co ordinate your care and help you when you come upon a stumbling block - just like this. Your cancer treatment center may well be able to answer some of your Q's too, they take a very holistic view of care and know ways around this stuff. BTW, my Mum also developed A Fib after surgery for colon cancer and has had troubles ever since, though is very reluctant to seek any real solution by way of second opinion.
Check out my site www.lumponablog.com. I have a couple of posts in the heart disease section that point to sites where you can check out hosptial death rates for certain conditions and also compare hospitals and search by zip code.
From there, I would call the hosptial or hospitals of choice and have them send you a list of the practicing cardiologists at their location. Once you have narrowed it down to a couple of doctors you can actually do research on them - it costs about $25.00 - $35.00 for a full report. Just google the doctors name and I assure you in the Google main ads section there will be a box with the link to perform the background check.
You could also Google Best Docs and your state and condition. Do the same with Best Doctors, Top Docs, and Top Doctors. Here in Austin I was able to find a link to Texas Monthly where the Austin Heart hostpital was labled as the top hosptial in the area. The article also listed the top doctors, and also what was titled super doctor - all of them at the Austin Heart Hospital. These surveys are provided to other doctors and ask the question that if you or a loved one has heart disease which doctor would you send them to? If you can find a survey for your state or city that would also be a good place to start.
Of course, it goes without saying that the Cleveland Clinic is the best hospital for heart disease in the country. I also have a link on my site to a USA today article that lists the top heart hospitals in the country. Maybe one of them is close to you.
Best of luck to you. Sounds like you have been through a lot. Here's to a great future!