Dear Abhishek,
Different heart conditions/diseases have different medical treatment. Few are simple to treat and many are much more complicated and requires Cardiologists’ opinion. These conditions vary in severity and nature and there is limitation one can comment on generalized treatment of Cardiology diseases because the medical treatment also varies and personalized looking at the disease and condition of the patients.
Regarding the life style changes to prevent heart disease are simple and easy to read but much more difficult to adopt.

1. Diet: low fat diet and low sugar diet
2. Exercise: As Per age group you can exercise best is at least walking for 45 minutes every day and if every day not possible than at least 4 days a week
3. Smoking: Cigarette smoking increases the risk of MI by 21% so quite smoking and tobacco habits
4. Alcohol: Any amount of alcohol is not healthy as per recently concluding evidences so stop drinking
5. Yoga and Meditation: This helps to reduce stress and anxiety
6. Diabetes: Common co-morbidity, so please take your medicines regularly and check your sugar as per your doctor’s advice
7. Weight: Control/Reduce weight and manage it well
8. Sleep: take rest properly and sleep at least for 7-8 hours a day

These are few general advices that can be given to the high risk group.

Abhishek,
While there are various types of cardiovascular disease, my guess is that you are most concerned about myocardial infarction, or "heart attacks". While some individuals have a genetic predisposition to them, for most they result from years of poor diet, high stress, and lack of physical activity, which leads to atherosclerosis (some call this hardening of the arteries). Atherosclerosis is a process where fatty deposits build up inside the arteries (plaque) and begin to calcify as you age. This process of build up within the arteries starts early in life, and the rate of build up depends on genetics, along with all the lifestyle choices I mentioned earlier. Most people don't realize there is a problem until the arteries become very narrow, due to the plaque buildup, and symptoms begin to occur. For most, this is age 40 and older, but there are individuals who even experience symptoms, including heart attack at a younger age than that. Some individuals are fortunate, and are able to notice symptoms, such as shortness of breath, dizziness, and chest or arm pain, which lead them to see a physician before they have a heart attack. However, there are individuals who do not realize there is a problem until they have a heart attack. The best thing to do is have a preventative checkups beginning in your 40s (or earlier if you have a family history of heart disease) and let the doctor run tests to see if there is any indication you are starting to suffer from a narrowing of the arteries that feed the heart. By the way, this process can also cause narrowing of the arteries in other areas of the body, such as the carotid arteries, which feed the brain (which can then lead to a stroke), or the arteries that feed the legs (leading to peripheral vascular disease). The best things to do to prevent heart disease is eat a diet low in fat and cholesterol (being a vegetarian is optimal), exercise at least 5 days per week (moderate intensity for 45 minutes to 1 hour), and practice relaxation techniques to reduce stress. Dr. Dean Ornish's program, which does all these things, is the ONLY treatment that has ever been proven to actually reverse plaque buildup in the arteries. Surgeries and medications do not reverse plaque buildup, they merely work to find ways to open clogged arteries, or bypass them. Best wishes!

I am a Naturopathic Doctor so I always try to do things naturally. They will need to change their lifestyle to start with. That means an exercise regimen and healthy eating. The exercise should be light at first like walking and stretching and gradually move up. The diet is the main change. They have to cut out all processed foods, sugar, artificial sugars except stevia and have healthy fats, lower carbohydrates from vegetables and fruits and all natural proteins with no chemicals or GMO's. They also need to make sure they reduce stress through meditation, relaxing, doing things they really enjoy, yoga and simply pilates if they are up to it. They we have to monitor these changes for a while to see the next steps.

Abhishek,
From a nutritionist point of view, I would support a Paleo approach with the elimination of all gluten, grain, sugar, dairy + these specifics can be helpful:
Health fats*: Wild salmon/tuna/sardines/almonds (all forms)/flaxseeds ( if no testosterone problems)/walnuts

• Veggies: broccoli/carrots (tri-colored)/spinach/sweet potatoes
• Fruits: berries (blue)/tomatoes/oranges
• Botanicals: CoQ10/turmeric/Rhodiola/Astaxanthin/nattokinase