How to diagnose Coronary Heart Disease ? 

Your doctor will diagnose coronary heart disease (CHD) based on your medical and family histories, your risk factors for CHD, a physical exam, and the results from tests and procedures.
                
No single test can diagnose CHD. If your doctor thinks you have CHD, he or she may recommend one or more of the following tests.
                
EKG (Electrocardiogram)
                
An EKG is a simple, painless test that detects and records the heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through the heart.
                
An EKG can show signs of heart damage due to CHD and signs of a previous or current heart attack.
                
Stress Testing
                
During stress testing, you exercise to make your heart work hard and beat fast while heart tests are done. If you can't exercise, you may be given medicine to raise your heart rate.
                
When your heart is working hard and beating fast, it needs more blood and oxygen. Plaque-narrowed arteries can't supply enough oxygen-rich blood to meet your heart's needs.
                
A stress test can show possible signs and symptoms of CHD, such as:
                
Abnormal changes in your heart rate or blood pressure
                
Shortness of breath or chest pain
                
Abnormal changes in your heart rhythm or your heart's electrical activity
                
If you can't exercise for as long as what is considered normal for someone your age, your heart may not be getting enough oxygen-rich blood. However, other factors also can prevent you from exercising long enough (for example, lung diseases, anemia, or poor general fitness).
                
As part of some stress tests, pictures are taken of your heart while you exercise and while you rest. These imaging stress tests can show how well blood is flowing in your heart and how well your heart pumps blood when it beats.
                
Echocardiography
                
Echocardiography(echo) uses sound waves to create a moving picture of your heart. The picture shows the size and shape of your heart and how well your heart chambers and valves are working.
                
Echo also can show areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.
                
Chest X Ray
                
A chest x ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels.
                
A chest x ray can reveal signs of heart failure, as well as lung disorders and other causes of symptoms not related to CHD.
                
Blood Tests
                
Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels might be a sign that you're at risk for CHD.
                
Coronary Angiography and Cardiac Catheterization
                
Your doctor may recommend coronary angiography (an-jee-OG-rah-fee) if other tests or factors show that you're likely to have CHD. This test uses dye and special x rays to show the insides of your coronary arteries.
                
To get the dye into your coronary arteries, your doctor will use a procedure called cardiac catheterization (KATH-eh-ter-ih-ZA-shun).
                
A thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. The tube is threaded into your coronary arteries, and the dye is released into your bloodstream.
                
Special x rays are taken while the dye is flowing through your coronary arteries. The dye lets your doctor study the flow of blood through your heart and blood vessels.
                
Cardiac catheterization usually is done in a hospital. You're awake during the procedure. It usually causes little or no pain, although you may feel some soreness in the blood vessel where your doctor inserts the catheter.