Use of heart rate responses to standing and hyperventilation at rest to detect coronary artery disease: correlation with the S-T response to exercise.

The heart rate responses to standing and to hyperventilation, expressed as a percent change over the sitting heart rate value, were measured in 48 patients with angiographic coronary artery disease (less than or equal to 70 percent luminal narrowing) and 50 young, healthy asymptomatic individuals. When an abnormal response suggesting coronary artery disease was defined as an increase in the heart rate of < 15% over the sitting value and < 20% increase in the heart rate to hyperventilation relative to the sitting value, the sensitivity of such a criterion was 56%, the specificity was 92% and the predictive value was 87%. These values were not significantly different (P > 0.05) from those for the S-T response to exercise, which were 77%, 98%, and 97% respectively. When either a positive S-T response to exercise or a positive response for control heart rate changes to standing and hyperventilation were used as criteria for a positive test, the sensitivity significantly increased to 98% (P < 0.01), while specificity and predictive value remained significantly unchanged (P > 0.05) at 90% for each. The use of the heart rate response to standing and hyperventilation may be a useful test in detecting coronary artery disease in patients unable to undergo stress testing. The use of such heart rate responses in addition to S-T depression with exercise results in a highly sensitive and specific test with great predictive value.