Section 2: Radionuclide Myocardial Perfusion Imaging: Procedures and Interpretation
When performing dipyridamole stress testing to establish the presence or absence of ischemic heart disease, which of the following medications may be given within 12 h before the test?
c. Oral dipyridamole does not impact on the vasodilatory effects of IV dipyridamole. However, the use of antianginal agents, such as beta blockers and nitrates, will reduce the ability to detect ischemia. Theophylline and caffeine are both methylxanthines and are competitive antagonists of dipyridamole at the receptor level and must be withheld prior to the test.
Exercise SPECT myocardial perfusion imaging is recommended for which of the following patients?
a. 65-year-old man within 48 h of a confirmed diagnosis of an acute coronary syndrome.
b. 71-year-old asymptomatic man who had a stent to LAD performed 18 months ago.
c. 37-year-old man with strong family history of CAD and reportedly with a normal stress ECG in past.
d. 62-year-old diabetic woman with new jaw pain.
e. 78-year-old man with dyspnea and LBBB on ECG.
d. The option "a" is incorrect as exercise testing within 48 h of an ACS is contraindicated. The performance of SPECT imaging in an asymptomatic patient <2 years after PCI is felt to be inappropriate (b). An asymptomatic man with a normal stress test (c) should not prompt further testing even in the setting of a family history of CAD. A LBBB is a relative contraindication for exercise SPECT, as vasodilator stress is recommended (option "e").
Which of the following pharmacologic protocols is not endorsed by guidelines?
a. 3-min adenosine infusion.
b. a graded dobutamine infusion up to 50 mcg/min.
c. a bolus of 400 mcg of regadenoson.
d. 0.56 mg/kg of diyridamole given over 4 min.
e. adjunctive exercise with adenosine.
a. A 4- or 6-min adenosine infusion is acceptable.
a. may be used safely in patients with asthma and/or COPD.
b. more frequently causes headaches than adenosine.
c. has frequently been associated with complete heart block.
d. requires the use of an infusion pump.
e. is contraindicated in the setting of frequent ventricular ectopy.