Diagnosed With IST Currently Taking Corlanor 2 X A Day.

diagnosed with IST currently taking corlanor 2 x a day. Helps lower rate but still shoots up to 130's when I am just sitting. I have a history of low blood pressure 90's over 60's but for last 6 months 80's over 50's is common and I feel very very bad when heart rate is high and blood pressure is low. Blood pressure shoots up to 140 over 90 sometimes which has never occurred in my history before the last few months. Is there anything else I can do to stop being out of breath so much?