Postischemic stunning after adenosine vasodilator stress

Ischemic left ventricular (LV) dysfunction may occur after exercise but is regarded as uncommon after vasodilator stress. We evaluated the prevalence of LV dysfunction after adenosine stress in relation to reversible perfusion defects and angiographic coronary artery disease (CAD).

We studied 86 patients referred for clinically indicated adenosine dual-isotope gated single photon emission computed tomography: 43 with 1 or more reversible perfusion defects (reversible defect group) and 43 age- and sex-matched patients with no known CAD and normal LV perfusion and function (control group). Coronary angiography was performed in 36 of 43 patients (84%) in the reversible defect group. Perfusion was interpreted based on 20-segment/5-point summed rest and stress scores. The extent of reversibility was defined by the summed difference score. LV ejection fraction and volumes at rest and 60 minutes after adenosine and segmental wall thickening were quantified by QGS (Cedars-Sinai Medical Center, Los Angeles, Calif). In patients with extensive reversible perfusion defects (summed difference score > or =8), 8 of 25 (32%) demonstrated depressed post-adenosine LV ejection fraction, abnormal segmental wall thickening, end-systolic dilation, and extensive CAD.

Adenosine is believed to be less likely than exercise to induce ischemia. However, myocardial stunning occurred in one third of the patients with severe reversible defects, consistent with ischemia.