COMPARISON OF MYOCARDIAL TL-201 CLEARANCE AFTER MAXIMAL AND SUBMAXIMAL EXERCISE - IMPLICATIONS FOR DIAGNOSIS OF CORONARY-DISEASE - CONCISE COMMUNICATION

  • 1 January 1982
    • journal article
    • research article
    • Vol. 23  (5) , 381-385
Abstract
The quantitation of regional 201Tl clearance increases the sensitivity of the scintigraphic detection of coronary disease. Although 201Tl clearance rates might be expected to vary with the degree of exercise, this relationship has not been explored. The rate of decrease in myocardial 201Tl activity was evaluated following maximal and submaximal stress in 7 normal subjects and 21 patients with chest pain, by using the 7-pinhole tomographic reconstruction technique. In normals, the mean 201Tl clearance rate declined from 41% .+-. 7 over a 3-h period with maximal exercise to 25% .+-. 5 after 3 h at a submaximal level (P < 0.001). Similar differences in clearance rates were found in the normally perfused regions of the left ventricle in patients with chest pain, depending on whether a maximal end point (defined as either the appearance of ischemia or reaching 85% of age-predicted heart rate) was achieved. In 5 patients who did not reach these end points, 3-h clearance rates in uninvolved regions averaged 25% .+-. 2, in contrast to a mean of 38% .+-. 5 for such regions in 15 patients who exercised to ischemia or an adequate heart rate. Evidently, clearance criteria derived from normals can be applied to patients who are stressed maximally, even if the duration of exercise is limited, but caution must be used in interpreting clearance rates in those who do not exercise to an accepted end point.

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