How do doctors diagnose angina?
The preliminary diagnosis of angina usually is made by the patient's history. The health care professional needs to understand what symptoms the patient is experiencing and may ask similar questions in a variety of ways to gain that understanding. This may be a frustrating process for both patient and professional because the symptoms of angina can range from classic to vague.
Part of the history will be to assess risk factors for heart disease. These include high blood pressure, high cholesterol, diabetes, family history, and smoking. Histories of stroke (cerebrovascular accident or CVA) or peripheral artery disease (PAD) are both risk factors since the mechanism of these diseases, hardening of the arteries or atherosclerosis are the same as for heart disease.
There are other diseases that can cause chest pain, abdominal pain, shortness of breath, sweating, and nausea and vomiting. Questions may be asked to determine whether other possibilities other than angina exist. Pulmonary embolism, pneumonia, aortic aneurysm, gastroesophageal reflux disease (GERD), peptic ulcer disease, and gallbladder disease are bit a few of the potential causes of symptoms other than angina.
Physical examination will help narrow the potential list of diseases but in of itself, will not make the formal diagnosis.
This is the time that the health care professional has to make a clinical decision as to the source of symptoms. If the tentative or provisional diagnosis is angina, a further decision has to be made whether it is stable or unstable.
With stable angina, a defined exercise will bring on the symptoms and rest will make it better. For example, a patient gets chest discomfort after walking 2 miles and it gets better with 5 minutes of rest. The pain pattern is constant and the amount of exercise required to bring on the symptoms has not been getting shorter. Often a patient with known angina will take a nitroglycerin pill to resolve the pain and it does so promptly.
Unstable angina usually happens at rest, wakens the patient at night, or comes on with minimal activity. These are times when the heart muscle is not being asked to work harder and yet angina symptoms may be present. Unstable angina is a potential warning sign of impending heart attack. There may be a transition from stable to unstable and the patient may describe decreasing amounts of exertion needed to bring on the angina symptoms.
Over time, a patient with angina may have their symptoms brought on by less and less activity. This progression needs to be monitored closely by both patient and doctor. The frequency of nitroglycerin use may be a clue that a coronary artery might be getting critically narrow increasing the risk of heart attack.
If angina is the major consideration, then an electrocardiogram (EKG) is usually performed. The electrical signal tracing of the heart can be interpreted to decide if heart muscle is damaged. The initial EKGs most important function is to decide if the patient is in the midst of suffering a heart attack or myocardial infarction (MI). This is a medical emergency.
If the EKG does not show a new heart attack and if the patient has stable symptoms, the next step depends upon the situation. Blood tests may be done to check cardiac enzymes. These are chemicals (troponin, CPK, myoglobin) contained in heart muscle cells that may leak into the bloodstream if the cell is injured. If the chemicals are not detected, then the presumption is that if the pain is due to ASHD, critical narrowing has not caused heart muscle damage. However, the tests need to be done and interpreted based upon the clinical situation.
With a stable EKG, resolved symptoms, and concern still present that the patient has angina, tests to image the heart may be considered. These may include one or more of the following: stress tests, nuclear imaging, echocardiogram, cardiac CT scan, and heart catheterization. The decision as to what test is most appropriate depends upon the patient, their symptoms, underlying health, risk factors, and the level of concern of the health care professional.