Symptom-limited arm exercise increases detection of ischemia during dipyridamole tomographic thallium stress testing in patients with coronary artery disease

Exercise combined with dipyridamole during thallium stress testing in patients with coronary artery disease (CAD) increases the frequency of angina and ischemic ST changes in the electrocardiogram. Evidence for an increase in thallium abnormalities has been inconclusive. We prospectively examined 54 consecutive patients who underwent coronary angiography and tomographic thallium with dipyridamole (0.57 mg/kg) alone and combined with symptom-limited dynamic arm exercise. Most patients presented with a history of chest pain and 49 had angiographic evidence of significant coronary stenosis (50% diameter narrowing). Thallium abnormalities were scored blindly by consensus. The number of abnormal segments (total and ischemic) and indexes of left ventricular dysfunction, such as increased lung uptake or ischemic dilation, were compared in the 49 patients with CAD. During arm exercise more patients had evidence of ischemia (39 vs 30; p < 0.001), and the number of ischemic segments increased significantly from 1.3 ± 1.5 to 2.5 ± 2.2 (p < 0.001). There was also a significant increase in the indexes of left ventricular dysfunction, ischemic dilation (10 vs 4 patients; p < 0.03) and increased lung uptake (16 vs 5 patients; p < 0.001). Patients who exercised had increased thallium evidence of extent and severity of ischemia and more frequent indexes of left ventricular dysfunction. Thus, symptom-limited arm exercise improves detection of extent and severity of ischemia in patients with CAD undergoing dipyridamole thallium stress testing.