Exercise electrocardiography testing in patients with aortic stenosis: Differential features from that of coronary artery disease

Background: Studies that have been conducted with exercise testing in patients with aortic stenosis (AS) have demonstrated that results of an exercise test can mimic coronary artery disease (CAD). The objective of our study was to investigate if there were any differential feature(s) of exercise testing in patients with AS compared to those with CAD. Methods: We prospectively studied 42 patients with AS (age 37 ± 23, range 8-75) with an averaged maximal gradient of 42 ± 19 mmHg (range 26-95). All patients had undergone a coronary angiography within 1 week of exercise testing and none had CAD. Another 100 patients with CAD, diagnosis proven with coronary angiography, comprised our second group for the comparison (CAD group). Cornell protocol was used in all patients. Results: ST segment depression was observed in all patients (160 ± 25 μV in AS group and 170 ± 20 μV in CAD group, P > 0.05). Thirty-four (81%) patients in the AS group and 88 (88%) patients in the CAD group exceeded the classical threshold for the test positivity (P > 0.05). ST/HR slopes derived from heart rate adjustment to ST segment level did not differ between the study groups (3.2 ± 2.3 and 3.7 p 2.2 μV/beat/min in AS and CAD groups, respectively, P > 0.05). Recovery phase patterns of ST segment in heart rate domain were different between AS and CAD (clockwise loop: 86% vs 0%; counterclockwise loop: 9% vs 88% in AS group and CAD group, respectively, both P < 0.001). Percentage of the intermediate loop was 5% in the AS group and 12% in the CAD group. Conclusions: Our study demonstrated that patients with AS could be distinguished from those with CAD with the method of rate-recovery loop analysis.