The diagnostic utility of heart rate-corrected ST-segment depression during adenosine nuclear stress testing.

Background: Vasodilator stress testing relies heavily on the imaging portion so that clinically useful information from the electrocardiogram may be overlooked. Stress-induced ST-segment depression, although uncommon, is highly predictive of severe disease. We investigated whether minor ST depressions during adenosine nuclear stress testing corrected for the modest heart rate increases (ST/HR slope and ST/HR index) might be clinically relevant.

Methods: The study included 74 consecutive patients with electrocardiograms interpretable for ischemia who underwent coronary angiography within the following 6 months.

Results: Abnormal responses using conventional thresholds for ischemic ST depression, the ST/HR slope, and ST/HR index were present in 8%, 20%, and 27%, respectively. The sensitivity for conventional ST depression was 11% and, when corrected for heart rate, increased to 27% and 36%, (P = .012), without adversely affecting the high positive predictive accuracy (83%, 80%, and 80%). Even with a normal perfusion scan, heart rate correction was highly predictive of multivessel coronary artery disease (4/5 patients).

Summary: Heart rate correction of ST depression during adenosine nuclear stress improves on conventional ST depression and may compliment perfusion imaging in detecting multivessel disease.