Sinus tachycardia. This for entire life?

Sir my mother had angioplasty last week in RCA TOWARDS PLV,LAD,RI TOTAL STENT -5 post angioplasty she developed atrial fibrillation for which doctor treated her with normad 2 ml and amiodarone injection and after 2 day inspection she became fine and discharged as she came home she again complaining of black vision and extreme dizziness and tiredness We have done her ech which shows sinus tachycardia and her heart' beat is always 150-170 bpm I want to know is this common to have afib post angioplasty and in how many days it will subside or will have live with this for entire life? Another cardiologist prescribed amiodarone 200 with some anti anxiety pills but still condition is same Pls help and suggest