I would recommend Dr. Sakib Nazir at Al Zahra Hospital. I've switched to two different cardiologists in the two years I've been living in Dubai but stayed with Dr. Nazir. He's very thorough and explains things well for the patient to understand.
Hope you find what you're looking for. I find it difficult to find a doctor that I could stick to. Building that rapport and trust with medical professionals seem elusive these days especially when you're in a foreign country.
Yes, Dr. Mittal, Head of Cardiology at Al Garhoud Private Hospital. He operated on me after I had a heart attack 18 months ago and he and the staff at the hospital were brilliant.