title: Pharmacologic stress perfusion imaging with adenosine: role of simultaneous low-level treadmill exercise.
abstract: BACKGROUND
  Adenosine is commonly used for pharmacologic stress myocardial perfusion imaging (MPI). However, it frequently results in adverse effects, and the subdiaphragmatic tracer uptake may interfere with the image interpretation. Our aim was to determine the feasibility of combining low-level treadmill exercise with adenosine MPI and its impact on adverse effects, image quality, and myocardial ischemia.
  
  
  RESULTS
  Forty-one patients underwent technetium 99m sestamibi single photon emission computed tomography following adenosine and adenosine with low-level exercise (adenosine-Ex) on separate occasions and rest MPI. A comparison was made of symptoms, hemodynamic response, electrocardiographic changes, image quality, and image interpretation between the 2 protocols. With adenosine-Ex, fewer patients had one or more adverse effects (61% vs 90%; P =.006), more patients had ischemic electrocardiographic changes (34% vs 15%; P =.03), a higher percentage had excellent- or fair-quality images (88% vs 61%; P =.003), and they had higher heart-liver ratios (1.0 +/- 0.37 vs 0.84 +/- 0.29; P =.002) compared with adenosine alone. Four adenosine MPI studies, but only 2 adenosine-Ex studies, were uninterpretable because of excessive subdiaphragmatic radiotracer activity. Of the 39 patients with at least 1 interpretable stress study, interpretation was discordant in 11 (28%): 7 showed greater ischemia with adenosine-Ex, 2 uninterpretable adenosine studies were interpretable with adenosine-Ex, and 2 studies interpreted as abnormal with adenosine were normal by adenosine-Ex (both had normal coronary angiograms).
  
  
  CONCLUSIONS
  Simultaneous low-level treadmill exercise with adenosine Tc-99m sestamibi imaging is safe and feasible, significantly reduces unfavorable side effects, enhances image quality, and may result in greater ischemia detection compared with adenosine alone.
authors: Division of Cardiovascular Medicine, University of Virginia Health Systems, Charlottesville, Va, USA.
authors: Habib
authors: H
authors: Samady
authors: Frans J Th
authors: FJ
authors: Wackers
authors: Tammy M
authors: TM
authors: Joska
authors: Barry L
authors: BL
authors: Zaret
authors: Diwakar
authors: D
authors: Jain
mesh_terms: D000241:Adenosine / Q000008:administration & dosage / Q000009:adverse effects; D000368:Aged; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine