Angina Pectoris – Investigations
- Blood glucose, creatinine, lipid measurement and urine examination may point towards diseases like diabetes, kidney disease or hypercholesterolaemia which may enhance atherosclerosis. Blood level of cardiac enzymes like CPK-MB, Troponin T and Troponin I are usually normal in angina but troponin T and troponin I level may be elevated in some cases of unstable angina.
- Electrocardiography (ECG)- It records the electrical changes in the heart through the electrodes placed on body surface. The ECG done at rest, may be normal. The typical changes which appear during the anginal attack and disappear afterwards, are characteristic of coronary artery disease.
- Treadmill test (TMT) or Exercise Electrocardiography – In TMT, continuous recording of ECG is done before, during and after exercise using treadmill or bicycle ergo meter. This test can also be used to assess the severity of coronary artery disease.
- Echocardiography (ECHO) – This is done with the help of a scanner which uses sound waves to get the picture of heart. Simply speaking it is the ultrasound of heart. ECHO can detect abnormality in movement in segments of heart wall (Dyskinetic segment) having deficient blood supply. It is done at rest and after exercise.
- Thallium perfusion scan – The radioactivity of these isotopes can be traced by special camera. Only the diseased part of heart takes up these radio isotopes in reduced amount and such areas can thus be demarcated. This test can be performed at rest or during exercise. This procedure is safe as exposure to radioactivity is minimal as in standard X-ray procedure.
- Angiography (coronary) – This is performed in a selected group of patients to confirm the presence of coronary artery disease. As the name suggests it outlines the coronary artery showing the site and severity of blockade. Dye is injected in the coronary arteries with the help of fine tube (catheter) passed through an artery in groin and series of film are taken. It is usually a safe procedure but some patients may have an allergic reaction to the dye. The process usually takes 45-60 minutes but 3-4 hour rest is required to avoid risk of bleeding from the punctured site. The punctured site may become bruised or tender for a few days after which it heals up.
In the tests involving exercise drugs such as adenosine and dipyridamole may be used as stress agent in patients WHO ARE UNABLE TO EXERCISE (e.g. osteoarthritis of knee).