My afib has been 99.9% controlled for over a year with flecainide. will having a colonoscopy risk that control?

Should be fine.: If you need a colonoscopy your A fib should not be affected by the procedure. Your heart will be monitored during the entire process. Make sure your physician is aware of your concerns. Normally if the benefits exceed the risk for testing we proceed with the procedure. Good luck.

Some risk: However, the benefit of getting your colonoscopy is greater than this small risk. Also if your afib goes out of control, it is correctable. Be well.

ManyThingsCanCareful: Flecainide, like other type 1 agents, track record is tripling death rates compared with placebo. Look up the CAST trial. The only agent without similar track record is amiodarone, has its own problems, yet fairly safe at low dose for many,many years. Better yet, also focus on artery disease drivers: optimize NMR lipoproteins (LDL <400 nmol/L, Large-HDL >9 μmol/L), HbA1c 5.0%, SBP <120 mmHg, etc.