Relative value of isotonic and isometric exercise radionuclide angiography to detect coronary heart disease

Isotonic and isometric stress have both been used in combination with radionuclide angiography to detect coronary heart disease. In view of the marked differences in these two forms of exercise and their relative advantages and disadvantages from a physiologic and a technical standpoint, these two techniques were compared in the same group of 48 patients undergoing diagnostic cardiac catheterization. All patients underwent first pass radionuclide angiography using a multicrystal camera at rest, during handgrip exercise and maximal bicycle exercise. Of the 48 patients, 28 had coronary artery disease and 20 had normal coronary arteries. Bicycle exercise resulted in a significantly higher rate-pressure product. Changes in global ejection fraction during handgrip exercise did not distinguish patients with or without disease. Eighty-two % of the patients with coronary artery disease showed an increase of less than 5 units in global ejection fraction during bicycle exercise. However, this criterion resulted in a low specificity of 30% in the patients with normal coronary arteries. In contrast, assessment of regional ejection fraction during bicycle exercise showed a sensitivity of 75% and a specificity of 65%. Handgrip exercise yielded a similar sensitivity of 68%, but the specificity was only 50%.Thus, in patients without evidence of severe left ventricular dysfunction at rest, upright bicycle exercise combined with radionuclide angiography and analysis of regional ejection fraction provides a more optimal combination of sensitivity and specificity compared with assessment of global ejection fraction or the use of isometric handgrip exercise