Can fluid accumulation in the lungs occur after nine years of bypass surgery?

Hello doctor,

My mother had open heart surgery, aortic valve, and bypass nine years ago; she has had an ejection fraction of 65 % since she was fine. Her medications are Concor 7.5 mg daily, Sintrom 4 according to the test, and Lanoxin, one tablet for five days a week. A year ago, she developed bradycardia, tachycardia, and an accumulation of fluid in the lungs, it was removed then they changed the medication to Cordarone and Lasix, but it did not resolve. She had fluid accumulation again. They changed it to Concor 5 mg daily, half in the morning and a half at night; Lasix, one tablet in the morning and a half tablet at night; Heperona, one tablet during the day; and Sintrom 4, according to the test. But she still has fatigue when she walks and fluid in her lungs; she never had this before. Kindly suggest.