The normal decline in systolic blood pressure (SBP) during the recovery phase of treadmill exercise does not occur in some patients with coronary artery disease (CAD). In others the recovery values of SBP exceed the peak exercise values. To examine the diagnostic value of this observation, we studied 31 normal subjects and 56 patients undergoing treadmill exercise before coronary cineangiography. Because of large differences in peak exercise pressures between the two groups, recovery ratios were derived by dividing the SBP at 1, 2, and 3 min after exercise by the peak exercise SBP. The 1, 2, and 3 min ratios in the normal subjects declined steadily from 0.85 0.07 (SD) to 0.79 + 0.06 and to 0.73 0.06, respectively, while the ratios in the patients with CAD remained elevated at 0.97 + 0.12 to 0.97 0.11 to 0.93 0.13. With use of the upper limits defined by two SDs of the normal value, recovery ratios were compared with the occurrence of angina and with ST segment depression on the exercise electrocardiogram in the patients with CAD. Abnormal ratios were more frequent in patients with CAD (53/56, 95%) than in those with ST segment depression (33/56, 59%), angina (37/56, 66%), and either ST segment depression or angina (42/56, 75%). Twenty of the patients with CAD who were on no medication underwent an additional treadmill exercise test on a separate day and no significant differences were found in the ratios from the two tests. Ten additional patients with CAD underwent treadmill exercise testing while on placebo and while on a fl-blocker. There were no significant differences in the ratios from the two tests. Twenty-eight of the 31 (90%) normal subjects had normal recovery ratios. We conclude that the ratios of early recovery SBP to the peak exercise SBP are more sensitive than exercise electrocardiographic changes and angina for identifying patients with CAD. Circulation 70, No. 6, 951-956, 1984. SINCE the original descriptions of electrocardiographic (ECG) changes during angina pectoris, la 2 numerous investigations have been conducted to assess the feasibility of increasing the sensitivity and specificity of the ECG for detecting ischemic heart disease.

SUMMARY We used M-mode echocardiography to measure left ventricular dimensions in diastole (Dd) and systole (Ds) and to assess ventricular performance by computing the percent dimensional shortening (%AD) and the normalized rate of dimensional shortening (Vd) during isometric and isotonic exercise in normal subjects. In 27 subjects, isometric handgrip exercise at 50% of maximum grip until fatigue produced a significant increase in Ds (33 ± 3.4 (SD) vs 30.6 i 3.7 mm, p < 0.001), and a reduction in %AD (34 ± 4 vs 39 ± 5%,p < 0.001) and Vd (1.15 ± 0.15 vs 1.28 0.19 sec-',p < 0.001). Handgrip exercise at 15% of maximum grip produced similar but less marked changes in the 27 subjects, and acute pressure loading with phenylephrine caused similar but more marked changes in 10 of the subjects. In the 20 subjects who performed at least 12 minutes of supine bicycle exercise, Ds decreased significantly (25.6 ± 4.0 vs 31.7 ± 2.8 mm, p < 0.001) and %AD increased (49 ± 6 vs 36 ± 5%,p < 0.001). We observed similar results in the 12 subjects also studied during upright bicycle exercise. Dd was smaller in the upright position but unchanged during either isometric or isotonic exercise. We conclude that: 1) end-diastolic left ventricular size is maintained during isometric exercise and moderate dynamic exercise, even in the upright position; 2) isometric exercise leads to a mild decrease in left ventricular shortening, whereas dynamic exercise results in marked increases in shortening; this difference may be related to the relatively greater increase in blood pressure than in heart rate during isometric exercise; and 3) M-mode echocardiography can be successfully accomplished in selected subjects during various forms of exercise. M-MODE ECHOCARDIOGRAPHY is an accurateand reproducible technique for assessing resting left ventricular size and performance in normal-sized hearts without segmental myocardial disease.'14 The sensitivity of this technique for detecting changes in left ventricular dynamics has been shown in studies evaluating the response to upright tilting,', the Valsalva maneuver,7 8 ventricular premature depolarizations,9 normal phasic respiration'0 and acute pharmacologic interventions with agents such as amyl nitrite, nitroglycerin, atropine and phenylephrine. 1" 12 One advantage of echocardiography is the ability to measure left ventricular diameters intermittently or continuously before, during and after an intervention without risk or discomfort to the subject and without affecting the normal response to the test conditions. Accordingly, we used echocardiography to measure left ventricular size and performance in normal subjects during isometric handgrip exercise and dynamic bicycle exercise in the supine and upright positions. MethodsThe study population consisted of 27 normal subjects who were selected from a group of twice as many because of excellent echocardiograms in the supine position at rest. There were 23 men and four women, ages 19-36 years. Physical fitness varied from subject

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