hypertension, or a smoking history. Nuclear stress tests are used in patients who have an abnormal resting electrocardiogram, while an angiogram should be performed in high-risk patients. The treadmill test alone is 70-90 percent sensitive, and 50-75 percent specific in detecting CAD, while a nuclear test is 81 percent sensitive and 85-95 percent specific. In either test, the test should be interpreted based on a compilation of the patient’s other findings and is not necessarily the most accurate test when used alone. It is better in detecting true ischemic changes and narrowing of the coronary artery lumen rather than generalized thickening of the artery. The cardiac stress test cannot be used in cases of recent MI (within 48 hours), unstable angina, uncontrolled heart arrhythmia, other certain heart diseases (valvular disease, pericarditis, or PE), multivessel disease that might precipitate an MI during testing, and decompensated congestive heart failure. Patients with severe hypertension (greater than 200/110), aortic dissection, other illness, and severe pulmonary hypertension cannot have a stress test. The test should be stopped if ST segment elevation occurs, the patient becomes extremely fatigued, there is evidence of hypoperfusion (cyanosis), the patient has moderate or severe chest pain, the patient develops dizziness or syncope, or the systolic blood pressure decreases instead of increases during exercise. Anyone with sustained ventricular tachycardia should not complete the test.
Angiography An angiogram is a more invasive test of the heart and directly evaluates the coronary arteries in suspected cases of coronary artery disease. The patient can also have this test done to look at the pulmonary vasculature, the peripheral vasculature, or the cerebral vasculature. The aorta and carotid arterial blood flow can be assessed with an angiogram.
Figure 6 describes a left coronary angiography picture:
Figure 6 8
