How is heart (cardiovascular) disease diagnosed?
The diagnosis of cardiovascular disease begins by taking the patient's history. The health-care professional needs to understand the patient's symptoms and this may be difficult. Often, health-care professionals ask about chest pain, but the patient may deny having pain because they perceive their symptoms as pressure or heaviness. Words also may have different meanings for different people. The patient may describe their discomfort as sharp, meaning intense, while the health-care professional may understand that term to mean stabbing. For that reason, it is important for the patient to be allowed to take the time to describe the symptoms in their own words and have the health-care professional try to clarify the terms being used.
The health-care professional may ask questions about the quality and quantity of pain, where it is located, and where it might travel or radiate. It is important to know about the associated symptoms including shortness of breath, sweating, nausea, vomiting, and indigestion, as well as malaise or fatigue.
The circumstances surrounding the symptoms are also important.
- Are the symptoms brought on by activity?
- Do they get better with rest?
- Since symptoms began, does less activity provoke onset of the symptoms?
- Do the symptoms wake the patient?
These are questions that may help decide wither the angina is stable, progressing, or becoming unstable.
- With stable angina, the activity that is required to initiate the symptoms does not fluctuate. For example, a patient may state that their symptoms are brought on by climbing up two flights of stairs or walking one mile.
- Progressive angina would find the patient stating that the symptoms are brought on by less activity than previously.
- In the case of unstable angina, symptoms may arise at rest or wake the patient from sleep.
Risk factors for cardiovascular disease should be assessed including the presence of high blood pressure, diabetes, high cholesterol, smoking history, and family history of cardiovascular disease. A past history of stroke or peripheral artery disease are also important risk factors to be assessed.
Physical examination may not necessarily help make the diagnosis of heart disease, but it can help decide whether other underlying medical problems may be the cause of the patient's symptoms.
There are some clues on physical exam that suggest the presence of narrowed arteries to the heart and coronary artery disease, for example, they the doctor may:
Check for high blood pressure.
Palpate. (feel) for the pulses in the wrists and feet to see if they are present, and if they are normal in their amplitude and force. Lack of pulses may signal a narrowed or blocked artery in the arm or leg. If one artery is narrowed, perhaps others, like the coronary arteries in the heart, also may be narrowed
Auscultating or listening to the neck, abdomen and groin for bruits. A bruit is the sound produced within a narrowed artery due to turbulence caused when decreased blood flow occurs across the narrowed area. Bruits can be heard easily with a stethoscope in the he carotid artery in the neck, the abdominal aorta, and the femoral artery .Check sensation in the feet for numbness, decreased sensation, and peripheral neuropathy.
Moreover, many other important conditions may need to be considered as the cause of symptoms. Examples include those arising from the lung (pulmonary embolus), the aorta (aortic dissection), the esophagus (GERD), and the abdomen (peptic ulcer disease, gallbladder disease).
After the history and physical examination are complete, the health-care professional may require more testing if heart disease is considered a potential diagnosis. There are different ways to evaluate the heart anatomy and function; the type and timing of a test needs to be individualized to each patient and their situation.
Most often, the health-care professional, perhaps in consultation with a cardiologist, will order the least invasive test possible to determine whether coronary artery disease is present. Although heart catheterization is the gold standard to define the anatomy of the heart and to confirm heart disease diagnosis (either with partial or complete blockage or no blockage), this is an invasive test and not necessarily indicated for many patients.
Electrocardiogram (EKG, ECG)
The heart is an electrical pump and electrodes on the skin can capture and record the impulses generated as electricity travels throughout the heart muscle. Heart muscle that has decreased blood supply conducts electricity differently than normal muscle and these changes can be seen on the EKG.
A normal EKG does not exclude cardiovascular disease and coronary artery blockage; there may be narrowing of the coronary arteries that has yet to cause heart muscle damage. An abnormal EKG may be a "normal" variant for that patient and the result has to be interpreted based upon the patient's circumstances.
If possible, an EKG should be compared to previous tracings looking for changes in the electrical conduction patterns.
It would make sense that during exercise, the heart is asked to work harder and if the heart could be monitored and evaluated during that exercise, a test might uncover abnormalities in heart function. That exercise may occur by asking the patient to walk on a treadmill or ride a bicycle while at the same time, an electrocardiogram is being performed. Medications (adenosine, persantine, dobutamine) can be used to stimulate the heart if the patient is unable to exercise because of poor conditioning, injury, or because of an underlying medical condition.
Ultrasound examination of the heart to evaluate the anatomy of the heart valves, the muscle, and its function may be performed by a cardiologist. This test may be ordered alone or it may be combined with a stress test to look at heart function during exercise.
A radioactive tracer that is injected into a vein can be used to indirectly assess blood flow to the heart. Technetium or thallium can be injected while a radioactive counter is used to map out how heart muscle cells absorb the radioactive chemical and how it is distributed in heart muscle cells may help determine indirectly whether a blockage exists. An area of the heart with no uptake would suggest that the area is not getting enough blood supply. This test may also be combined with an exercise test.
Cardiac computerized tomography (CT) and magnetic resonance imaging (MRI)
Using these scans, the anatomy of the coronary arteries can be evaluated, including how much calcium is present in the artery walls and whether blockage or artery narrowing are present. Each test has its benefits and limitations and the risks and benefits of considering a CT or MRI depends upon a patient's situation.
Cardiac catheterization is the gold standard for coronary artery testing. A cardiologist threads a thin tube through an artery in the groin, elbow, or wrist into the coronary arteries. Dye is injected to assess the anatomy and whether blockages are present. This is called a coronary angiogram.
If a blockage exists, it is possible that angioplasty may be performed. Using the same technique as the angiogram, a balloon is positioned at the site of the obstructing plaque. When the balloon is inflated, the plaque is squashed into the wall of the artery to re-establish blood flow. A stent may then be placed across the previously narrowed segment of artery to prevent it from narrowing again.