Hi, There can be various reasons for dizziness. It can be due to anemia, low blood sugar, prolonged fasting or vitamin deficiencies. Even stress and anxiety can also lead to such symptoms. Besides it can be due to problems related to ear( swelling , infection, benign positional vertigo), neck( cervical disc disease), or muscle strain. Since you already are on treatment for cardiac ailment it can be drug induced( the medicines you mentioned can cause electrolyte imbalance- abnormal salts in your body) or related to your cardiac disease. So I feel that first of all focus on your diet.Eat plenty of fruits and vegetable.Maintain proper posture especially while sleeping or working on computer. Regularly monitor your bp. Also if still your symptoms persist then go for some investigations like complete blood count,FBS,tsh, xray neck,Ecg and Kidney function tests.This will give you a proper diagnosis. I also feel that you should not reduce the dose of your medicine on your own,without consulting your treating doctor.In Fact if your symptoms persist you should go and discuss with him so that he can plan the treatment(the medicines and their doses) accordingly. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr. Milinda Gupta