It's a vast subject and a lot of findings/researches are in progress to address the situation and generate an awareness among peoples sufferings from Heart Ailments. I had an Heart Attack about 8 years back; gone through Angiography had 3 blockages( 30 – 70%). But I am now perfectly OK without Surgery but religiously following the Program For Reversing Heart Disease, as written & instructed by Dr. Dean Ornish.
Yes, high HDL Cholesterol is good for Heart and high LDL is bad for Heart.I have understood the basic things to control this elements of Cholesterol. Exercises raises HDL, where as smoking lowers it. Stress management training will lower LDL independent of diet.
So the best combination for reversing Heart Disease is to exercise, stop smoking, eat a very balanced diet(low fat low calorie) if possible Vegetarian diet.

Cholesterol does not cause coronary artery disease at all

Having elevated fasting blood sugar , blood pressure, homocysteine and poor nitric oxide levels do