Test-retest reproducibility of heart rate recovery after treadmill exercise.

BACKGROUND Slowed heart rate recovery (HRR) of less than 12 beats per minute in the first minute after an exercise stress test has been suggested as a useful addition to the criteria currently used to assess exercise stress test results. Although HRR has been tested in large populations, the short-term test-retest stability (reproducibility) of abnormal HRR for an individual has not been assessed. METHODS The study was a retrospective comparison of medical record information using a community-practice-based sample of 90 patients undergoing 2 exercise stress tests separated by 18 weeks or less. Concordance of abnormal HRR results on the first and second stress tests were assessed for individual patients using definitions of abnormal HRR from the medical literature. RESULTS Individual patient's HRR was markedly variable from the first to second stress test. In this sample, no definition of abnormal HRR provided more than 55% concordance between results from the first and second stress tests. CONCLUSION These preliminary data suggest that HRR appears to have limited short-term test-retest stability or reproducibility and therefore might not be a reliable addition to current results of exercise stress tests.