May 1, 1985Heart31 citationsOpen Access
Predictive value and limitations of the ST/HR slope.
Key Result
The exercise ST/HR slope accurately detected coronary disease in stable angina (91%) but yielded false negatives in 36% of recent MI patients and false positives in 88% with aortic regurgitation.
Study Design
Type
Observational (n=135)
Structured PICO
Does the exercise ST/HR slope accurately detect coronary artery disease across different patient populations including stable angina, recent myocardial infarction, and aortic regurgitation?
P
Population
135 subjects including 50 patients with stable angina, 17 normal subjects, 51 patients tested within three weeks of acute myocardial infarction, and 17 patients with important aortic regurgitation but no coronary disease.
I
Intervention
Exercise ST/HR slope measurement
C
Comparator
Comparison across different patient groups (stable angina, normal subjects, recent myocardial infarction, and aortic regurgitation)
O
Outcome
Diagnostic accuracy (false positive and false negative rates) of the exercise ST/HR slopesurrogate
The exercise ST/HR slope is accurate for detecting coronary disease in stable angina but is limited by high false negative rates after recent myocardial infarction and high false positive rates in patients with aortic regurgitation.
Abstract
To assess the value and predictive limitations of the exercise ST/HR slope, exercise test results were compared in 50 patients with stable angina and in 17 normal subjects with those in two groups known to have a high prevalence of inaccurate electrocardiographic responses to exercise. The last two groups included 51 patients tested within three weeks of acute myocardial infarction and 17 with important aortic regurgitation but no coronary disease. Of the normal subjects, 16 (94%) had ST/HR values less than or equal to 1 X 1 microV/beat/min. Of those with stable angina pectoris, 42 of 46 (91%) patients with coronary artery disease had ST/HR slopes ranging from 1 X 2 to 20 X 0 microV/beat/min, with false negative findings (slopes less than or equal to 1 X 1 microV/beat/min) in only four (9%). In contrast, of those with recent myocardial infarction, 15 of 42 (36%) with coronary disease had false negative slopes, including 12 of 20 (60%) with anterior wall injury. Of those with aortic regurgitation, conversely, 14 of 16 (88%) patients with calculable ST/HR slopes had values greater than 1 X 1 microV/beat/min despite the absence of coronary disease. Despite the accuracy of the test in patients with stable angina, false negative results are common in those after recent myocardial infarction, and false positive results occur often in those with abnormal volume loading due to aortic regurgitation.