Review Question - QID 103717

The patient has chest pain at rest with an indeterminate EKG due to LBBB and normal troponins. The presentation suggests unstable angina and further risk stratification is warranted.

Low risk patients with unstable angina should be admitted to the hospital for further risk stratification, and an exercise or pharmacologic stress echo should be performed. Unstable angina in high risk patients, such as those with known CAD, greater than 3 CAD risk factors, or ST depressions greater than 1mm, or those patients with elevated cardiac biomarkers (NSTEMI) should be sent for angiography. This patient's LBBB may mask EKG signs of cardiac ischemia, and he has a history of exertional angina which limits his ability to exercise. Adenosine perfusion stress tests are more sensitive than exercise stress tests in patients with significant baseline EKG abnormalities or an inability to exercise to an adequate level.

Rivitz and Deluca write, “Perfusion imaging is useful for both diagnosis and prognosis in patients with coronary artery disease. In patients unable to exercise, the coronary vasodilators dipyridamole and adenosine may be used in conjunction with thallium imaging.”

Banerjee et al. report that adenosine perfusion testing and exercise echocardiography were more sensitive than exercise EKG for coronary artery disease in a meta-analysis of over 3000 patients.

Illustration A shows a normal myocardial perfusion test demonstrating unimpaired perfusion of the heart in a healthy patient.

Incorrect Answers:
Answers 1-3: The patient has symptoms of CAD. The presence and extent of his CAD should be measured before he leaves the hospital.
Answer 5: The patient’s angina makes him a poor candidate for exercise tests. Additionally, exercise EKG is less sensitive than adenosine perfusion imaging or exercise echocardiography.