Coronary disease is best diagnosed by a person’s medical history and a medical check-up by their doctor. If a patient exhibits any of the symptoms listed and/or has several of the risk factors, the patient should go for a heart check-up. Currently there are several ways to help diagnose the presence of coronary disease.
Commonly used methods for heart check-ups are:
ECG measures the electrical activity of the heart to to test how well your heart is functioning. Electrodes are placed on the skin of the chest and of the arms and legs. On the electrocardiogram, the pulse beats of the heart are shown as waves. Each time the heart beats, it produces the wave shown in the image.
ECG can be used to determine:
- Irregular or abnormal heartbeats (arrhythmia)
- Decrease in blood or oxygen supply to the heart
- Previous heart attacks
- Damage to heart tissues
Exercise Stress Test
If a patient has chest pains and the doctor suspects it is due to coronary disease, the doctor will usually suggest an exercise endurance test. Electrodes connected to an ECG machine will be attached to the patient while the patient walks on a treadmill. The treadmill is slightly tilted to simulate going up a hill and it gradually increases in speed during the test which requires the patient to walk faster.
As the body exerts more effort to walk and then run faster, the heart will require more blood and the heart beats faster. As the heart beats faster the blood pressure will go up. If the blood supply to the heart is not enough for the faster speeds, the ECG will display irregularities.
Through the exercise stress test, the doctor can diagnose problems with the heart blood vessels being blocked and also more accurately determine what level of exercise is most suitable for the patient.
Myocardial Perfusion Scan (MIBI)
When the doctor wants to know more about the heart’s blood supply and suspects the narrowing of coronary arteries, a nuclear scan may be required. The patient will be injected with a small amount of radioactive material (called thallium or MIBI). The patient lies on a special bed with a camera above (gamma camera) which takes pictures of radioactive activity. If a portion of the heart does not receive normal blood supply it will show as a blank space in the scanned image.
The first set of images is taken while the patient is at rest. Then the patient does the exercise stress test. A second set of images is taken after the patient completes the exercise. If the patient cannot perform the exercise due to muscle of skeletal problems, the patient may be prescribed dipyridamole (Dipyridamole or Persantine) to simulate the effect of actual exercise.
An echocardiogram is a test that uses sound waves to record the heart’s motion This test allows the doctor to check the functioning of the heart and its valves. When the patient has abnormal heart murmurs, has previously had a heart attack, or is suspected of having valve issues, an echocardiogram is required.
Computer Tomography (CT Scan)
CT scans use x-ray and sophisticated computer technology to obtain “the most conclusive” image. During the scan, the patient lies down on a narrow table and the body is pushed into the machine. Usually a pigmented substance is injected into the veins of the patient to enable the doctor to see the vascular network of the heart. Some patients may have a sensitivity to this pigment and the scan can be done without it in this case. If you belong to this group, inform your doctor when he schedules the scan.
CT scans allows the doctor to clearly see the heart’s arteries, intravascular fat deposits, and any damage or death in the heart tissues.
Magnetic Resonance Imaging (MRI)
MRI uses magnetic fields and radio waves of different frequencies to take high quality images of the heart. It does not use x-ray. MRI is very useful for people with congenital heart problems or for determining the extent of heart damage in people who have had heart attacks.
Coronary Angiography (Cath)
Coronary angiography enables the doctor to observe the heart and its blood vessels. Although other tests (such as MIBI or CT scan) can assist the doctor in diagnosing blockage in coronary arteries, coronary angiography is the most effective method. It is done in the hospital. The doctor usually threads a small tube from the patient’s femoral artery or wrist artery into the coronary arteries. X-ray dye is injected into the coronary arteries and flows into the smaller arteries of the heart. The path of the dye and any interruptions is recorded.
If the heart has severe blockages, a balloon angioplasty or a stent placement can be done. If a heart bypass surgery is required, it can also be done after this procedure.
Content by Dr. Anthony Fung, Cardiologist
- Quit smoking: Not only does this reduce the chance of you getting heart disease or if you already have heart disease then having it get worse, it also reduces the risk of stroke and lung cancer.
- Control high blood pressure: The usual goal is to keep blood pressure below 140/90 mmHg. In certain cases (for patients with diabetes, kidney failure or heart failure) the doctor will set an even lower goal.
- Control cholesterol levels: For people with coronary disease and diabetes, doctors will have stricter guidelines than for the general public. Borderline levels of cholesterol are definitely not good enough. Patients must ask their doctors for an acceptable cholesterol level for them since it is dependent on their coronary situation. To get a patient’s cholesterol level to where it should be usually requires both a controlled diet and medication.
- Control diabetes: Maintaining a healthy glucose level decreases the risk of diabetic complications, including the risk of cardiovascular disease complications.
- Control body weight: Patients should maintain a reasonable weight based on their gender and height. The waistline is also an important guide for preventing vascular diseases. A reasonable waistline for Asian men is less than 35 cm and for Asian women is less than 31 cm.
- Exercise regularly: Exercise at least four times a week for 30 minutes each time.
Medication for Coronary Disease
- Nitroglycerin mouth sprays and nitroglycerin tablets placed under the tongue can be used for quick relief of chest pains. Those who frequently experience chest pains should always carry either the spray or tablets. If these do not help the chest pain the patient should go to the Emergency room.
- Oral nitroglycerin tablets or skin patches are used to prevent the return of chest pains (note: skin patches should stay on for 12 hours)
Blood thinners (Anti-platelet drugs)
- These drugs help prevent blood clots from forming in the blood and blocking the blood vessels. This reduces the risk of heart attacks.
- Aspirin is the most common drug of this type. If the patient has adverse reactions to aspirin, Clopidogrel (Plavix) may be used instead. In more severe cases Warfarin can be used.
- After a procedure such as balloon angioplasty or stent placements the patient is usually prescribed aspirin and Clopidogrel (Plavix). The medication is required from anywhere between a month to a year depending on the type of balloon or stent inserted. Failure to continue with medication can increase the risk of sudden blood vessel blockages and heart attacks.
- Helpful in the treatment of chest pains
- Helps prevent another heart attack
- Used to treat heart failure (weakened hearts)
- Used to treat irregular heart beats
ACEI-Angiotensin Converting Enzyme Inhibitors
- Used to treat heart failure (shows good results when taken with B-blockers)
- Used to treat high blood pressure
- Used to treat kidney failure especially when related to diabetes
- One side effect observed among Chinese people is a dry cough. In this case another group of drug unlikely to cause a cough can be substituted (ARBs: Angiotensin Receptor Blockers)
Content by Dr. P.K. Lee, Cardiologist