Yes, I had to go off of Letrozole and then Anastrozole when both of them kept raising my blood pressure. I initially had moderately high blood pressure but didn't have arrhythmia really, just occasional palpitations, and was on a Beta-blocker, then added in Amlodipine, (a Calcium channel blocker) and Olmesartan (an ARB) as my BP climbed. After 4 months on AI's my BP suddenly changed and became "labile", with me ending up in ER more than once, with BP's of 200/100. So I quite the AI's.....I am still stuck with the labile hypertension, and it is not fun, taking the super drug Hydralazine if it spikes high. I have read research that says people with cardiovascular disease shouldn't take AI's, but would have to look for that again. ~ Patty (Jardinera)