Assessment of cardiac stress tests

Objective: The goal of our study was to perform a quality assurance evaluation of our nuclear cardiology laboratory to ensure that patients who underwent exercise stress testing reached an adequate exercise level to accurately evaluate coronary blood flow with a nuclear cardiology perfusion scan. Methods: We evaluated 282 outpatient cardiac stress test studies. A drug usage evaluation checklist was completed for each patient to determine what test to perform on the patient. Results: Exercise stress tests were done on 180 of 282 patients (63.8%), and 102 of 282 (36.2%) had pharmacologic stress testing. Of exercise stress test patients, 145 of 180 (80.6%) met at least one of the criteria and the exercise was considered adequate. Of the 35 patients who did not meet any of the criteria, 26 (74.3%) were on calcium channel antagonists or beta blockers. Conclusions: We concluded: (1) 80% of the exercise stress tests done in our laboratory are adequate by usual criteria; (2) reaching a heart rate ≥ 85% of maximum comprised the majority of the adequate tests (>80%); (3) ischemic end points (angina, positive ECG or both) at a lower heart rate occurred in < 20% of the adequate tests; (4) most patients with inadequate tests were on pharmacologic therapy; and (5) further DUE study is necessary to determine if the inadequate tests still provide adequate data for clinical decision making.