Hello! Thank you for your question! Regarding your concern I recommend you to perform an ambulatory 24 hours BP monitoring and also an ambulatory 24 to 48 hours ECG monitoring. As your complains are becoming more frequently and repeated on a daily basis these exams will surely clarify the exact cardio-vascular cause of dizziness if really exists any. You referred for a past history of cardiac problems (heart attack and stent implantation); I would need more additional information about the recent cardiac echo report (if it exists), and the real complication of that heart attack (was it a myocardial infarction or only unstable chest angina), because if a clearly important heart damage has happened before probably there exists now a potential substrate for possible arrhythmic or hypotensive events (responsible for your dizziness); if all this reasoning come true than you should discuss for a treatment modification and follow up schedule. If in the other side nothing is confirmed by all the cardiac screening then you must consult wit ha neurologist. Hope to have been helpful to you. Greetings from Dr. Iliri.