Diagnostic value of the ratio of recovery systolic blood pressure to peak exercise systolic blood pressure for the detection of coronary artery disease

It has been previously reported that at treadmill exercise testing an abnormal ratio of recovery systolic blood pressure (SBP) to peak exercise SBP is more sensitive than exercise-induced angina or ST segment depression for diagnosing coronary artery disease (CAD). To investigate whether the SBP ratio keeps its diagnostic value during upright bicycle exercise, we evaluated the ratio of postexercise SBP to peak SBP in 73 patients with angiographically documented CAD and in 48 patients with normal coronary arteries (OV group) undergoing maximal stress testing on a bicycle ergometer. Three minutes after exercise ended, SBP ratio was significantly higher in the CAD than in the OV group (0.79 +/- 0.1 vs 0.71 +/- 0.08; p less than .001). Setting the upper normal limits of the recovery SBP ratio at 2 SDs from the mean for the OV group (SBP ratio = 0.98 and 0.88 at 1 and 3 min after exercise, respectively), with an increase or no change in SBP ratio at between 1 and 3 min of recovery considered an abnormal response, the sensitivity of SBP ratio was 30%, the specificity was 83%, and the accuracy was 51%. The respective values for ST depression were 81% (p less than .0001 vs SBP ratio), 48% (p less than .001 vs SBP ratio), and 67% (p less than .01 vs SBP ratio). Thus, for bicycle ergometer exercise testing, ST segment depression seems to be more accurate than SBP ratio in diagnosing CAD.     

Usefulness of the postexercise response of systolic blood pressure in the diagnosis of coronary artery disease

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 beta-blocker.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormal recovery systolic blood pressure response for detecting coronary artery disease in men and women investigated by upright bicycle exercise

We investigated the clinical significance of recovery systolic blood pressure (SBP) ratio, obtained dividing the recovery SBP at 1st (R1/A) or 3rd min (R3/A) by the peak exercise SBP (before stopping), during upright bicycle exercise in 530 subjects (ranging from 17 to 73 years). Our results may be summarized as follows: 1) we found a higher value of R1/A in control subjects with exercise induced ST depression; 2) the normal range in women was higher than in men; 3) the use of recovery SBP ratios gives a lower sensitivity and a higher specificity than ST segment analysis in detection of CAD; 4) this pattern may be useful particularly in patients with previous myocardial infarction and not detectable ST segment analysis during exercise.     

平板运动试验中室性早搏ST段下移诊断冠状动脉病变的价值

探讨平板运动试验中室性早搏(VPCs)ST段下移程度对反映冠状动脉(简称冠脉)病变的价值。将休息和平板运动试验中均发生VPCs并且在3个月内进行冠脉造影的92例患者按冠脉造影结果分成冠心病组和非冠心病组,比较两组VPCsST段下移程度,下移程度与冠脉狭窄程度的关系以及VPCsST段下移诊断冠心病的价值。结果:冠心病组运动中VPCsST段下移及ST/R均大于非冠心病组。其中ST/R>10%对冠心病诊断灵敏度为91%,特异度为75%;对单支、2支、3支血管病变诊断灵敏度分别为84%、91%、100%。冠脉狭窄≥90%组运动中VPCsST段下移和ST/R大于狭窄为50%~69%组。结论:运动试验中VPCsST段下移可作为诊断冠心病的有效参考指标,其下移程度可能与冠脉狭窄程度有关。     

Diagnostic usefulness of the post-exercise systolic blood pressure response for the detection of coronary artery disease in patients with diabetes mellitus

Patients with diabetes mellitus (DM) often have a positive result on exercise testing despite a normal coronary arteriogram, which indicates that exercise-induced ST depression is not always an accurate indicator of the presence of coronary artery disease (CAD) in such patients. The present study evaluated the usefulness of the post-exercise systolic blood pressure (SBP) response for the detection of CAD in 47 consecutive patients with DM. Significant stenotic lesions were detected by angiography in 25 patients; 18 of these had true positive (TP) exercise testing results, and 7 had false negative (FN) results. No significant stenotic lesions were detected in the remaining 22 patients and of these 10 had true negative (TN) exercise testing results, and 12 had false positive (FP) results. The SBP ratio (SBP after 3 min of recovery divided by the SBP at peak exercise) was significantly higher in patients with coronary stenoses than in those without. Analysis of the relative cumulative frequency revealed that a SBP ratio greater than 0.87 was associated with significant stenoses. The sensitivity, specificity, and accuracy of ST change combined with a SBP ratio greater than 0.87 for detecting stenoses in patients with DM were 68%, 82%, and 74%, respectively. These results suggest that calculating the SBP ratio, in combination with monitoring for ST depression, improves the accuracy of treadmill exercise testing for the detection of CAD in patients with DM.     

Assessment of coronary artery disease in hemodialysis patients with delayed systolic blood pressure response after exercise testing

BACKGROUND: We evaluated usefulness of the postexercise systolic blood pressure (SBP) response for detecting coronary artery disease (CAD) in hemodialysis patients. METHODS: A treadmill exercise testing was done, and the SBP response was measured in 44 hemodialysis patients (30 men, 14 women; age 41 to 81 years). The postexercise SBP response was defined as the ratio of SBP after 3 minutes of recovery to SBP at peak exercise. RESULTS: The SBP ratio of the 25 subjects with coronary artery stenosis (1.01+/- 0.13) was significantly greater (p<0.01) than 19 subjects without coronary artery stenosis (0.83+/- 0.10). An SBP ratio greater than 0.92 identified CAD with higher sensitivity, specificity, and accuracy than did the conventional ST-segment depression criterion (76 vs. 56%, 90 vs. 53%, and 82 vs. 55%, respectively). CONCLUSION: Determination of the SBP ratio is a clinically useful, noninvasive method for accurately detecting CAD in hemodialysis patients.     

Value and mechanism of abnormal postexercise systolic blood pressure response for detection of coronary artery disease]

The value of an abnormal ratio of recovery systolic blood pressure to peak exercise SBP for detecting coronary artery diseases (CAD) is controversial. We evaluated the ratio in 39 patients with angiographically documented CAD and 52 patients with normal coronary artery undergoing treadmill exercise. If a response with the ratio higher than 1.0 and 0.8 at 1 and 3 min. of recovery was considered as abnormal, the sensitivity for detecting CAD was 66.7%, the specificity 73.1% and the accuracy 70.3%. If ST segment depression is combined into the criteria, the specificity and accuracy reach 94.2% and 76.9%. In CAD, the ratio at 3 min. of recovery showed significant negative correlation with resting left ventricular ejection fraction (LVEF) (r = -0.461, P < 0.01). It is suggested that low resting LVEF may be one of the mechanism of this abnormal ratio in CAD.     

Effect of coronary artery disease on Doppler-derived parameters of aortic flow during upright exercise

Recent advances in Doppler echocardiography have made possible noninvasive determination of stroke volume, cardiac output and peak ejection velocity at rest. To determine the ability of Doppler to measure these variables and the effect of altered left ventricular (LV) function during upright treadmill exercise, 20 normal subjects (group I) and 17 patients with coronary artery disease (CAD) (group II) were studied. Stroke index response was similar in both groups. The increase in cardiac index was more rapid in group I subjects and reached a higher peak value at maximal exercise (8.6 +/- 2.5 vs 5.5 +/- 2.2 liters/min, p less than 0.001). Peak ejection velocity increased rapidly during exercise in group I subjects; it increased much less in group II patients. Differences were significant at each stage of exercise. Peak ejection velocity was 1.56 +/- 0.32 and 0.89 +/- 0.26 m/s in group I vs group II patients, respectively, at maximal exercise. Three responses were seen in group II subjects. Three patients, all with 1-vessel CAD and normal LV function at rest, showed a normal response, with an increase in peak ejection velocity of at least 80% (type I response). In 8 patients peak ejection velocity increased less than 80% (type II response) and in 6 patients it decreased at maximal exercise (type III). Type II and III responses were seen in patients with more severe CAD and LV dysfunction at rest. These data show a progressive difference in Doppler-derived variables in exercise between normal subjects and patients with CAD, which is greatest in patients with LV dysfunction at rest and multivessel CAD.     

Persistent ST segment depression in precordial leads V5-V6 after Q-wave anterior wall myocardial infarction is associated with restrictive physiology of the left ventricle

OBJECTIVES: To examine the relationship between the persistence of ST segment depression in leads V5-V6 after Q-wave anterior wall myocardial infarction (MI) and the filling pattern of the left ventricle (LV). BACKGROUND: Precordial ST segment depression predominantly in leads V5-V6 is associated with increased in-hospital morbidity and mortality after acute myocardial ischemia, perhaps due to reduced diastolic distensibility of the LV. METHODS: We prospectively studied 19 patients after Q-wave anterior wall MI (>6 months). All patients underwent 12-lead ECG recording, symptom-limited treadmill exercise testing with single photon emission computed tomography thallium-201 imaging, transthoracic Doppler echocardiography, cardiac catheterization and measurement of circulating atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels. Patients were classified based on the presence of ST segment depression in leads V5-V6: Group I = ST segment depression <0.1 mV (n = 10); Group II = ST segment depression > or =0.1 mV (n = 9). RESULTS: Patients in Group II had greater LV end diastolic pressures (32.4 +/- 6.5 mm Hg vs. 14.8 +/- 6.1 mm Hg; p = 0.0001), higher plasma ANP (44.4 +/- 47.1 pg/ml vs. 10.7 +/- 14 pg/ml; p = 0.04) and BNP levels (89.4 +/- 62.7 pg/ml vs. 23.6 +/- 33.1 pg/ml; p = 0.01), greater left atrium area (20.6 +/- 3.1 cm2 vs. 17.8 +/- 2.4 cm2; p = 0.05), lower peak atrial (A), higher early (E) mitral inflow velocities, a higher E/A ratio and a lower deceleration time (167 +/- 44 ms vs. 220 +/- 40 ms; p = 0.05). Lung thallium uptake during exercise was more common in Group II (78% vs. 10%, p = 0.04). CONCLUSIONS: Persistent ST segment depression in leads V5-V6 in survivors of Q-wave anterior wall MI is associated with increased LV filling pressure and a restrictive LV filling pattern.     

Usefulness of a novel ultrasound transducer for continuous monitoring treadmill exercise echocardiography to assess coronary artery disease.

BACKGROUND: The feasibility of a novel ultrasound probe, which can be attached to the left ventricular (LV) apex chest wall and allows free rotation around its long axis direction for the continuous monitoring of LV wall motion, was tested. METHODS AND RESULTS: There were 36 subjects who had coronary artery disease (CAD). By attaching a novel ultrasound probe to the chest wall, the LV apical views were recorded during treadmill exercise stress echocardiography (Echo). The continuous monitoring of LV wall motion was satisfactorily feasible in 30 of 36 patients. The visualization rate of the overall LV segments was higher at rest (90%) compared to that during peak exercise (77%). The segments were better visualized in apical portions (90-100%) than in mid (77-96%) or basal portions (68-87%). The sensitivity, specificity, and accuracy for detecting CAD were 61, 100 and 77%, respectively. The wall motion score index 3 and 6 min after exercise decreased significantly compared to those at peak exercise. The number of segments with dyssynergy was highest at the peak exercise. Ischemic ST-T depression on electrocardiography was observed only at peak stress periods. CONCLUSIONS: Continuous monitoring treadmill exercise Echo using a novel ultrasound probe seems feasible for the non-invasive and physiological assessment of CAD.     

The threshold for myocardial ischemia varies in patients with coronary artery disease depending on the exercise protocol

It is generally accepted that angina pectoris and, presumably, myocardial ischemia occur at a fixed heart rate-systolic blood pressure product in a given patient. This concept of a fixed threshold has recently been challenged. To evaluate the effects of varying exercise intensity on the ischemic threshold, 33 patients with coronary artery disease and provokable myocardial ischemia, documented by thallium-201 myocardial perfusion imaging, underwent two exercise tests 2 to 7 days apart. A symptom-limited incremental treadmill exercise test was followed by a 20 min submaximal treadmill test at an intensity approximating 70% of the peak heart rate attained during the incremental test. During the incremental exercise test, angina pectoris developed in 16 patients and 17 patients were asymptomatic. At least 0.1 mV of ST segment depression developed in all subjects during the incremental exercise test at a mean exercise duration of 5.3 +/- 2.6 min, a rate-pressure product of 19,130 +/- 5,735 and oxygen uptake of 19.6 +/- 7.0 ml/kg per min. During the submaximal exercise test, 28 (85%) of the 33 patients had significant ST segment depression. Of these patients, 24 (86%) were asymptomatic, including 10 patients who had previously reported anginal symptoms during the incremental test. The average time to onset of 0.1 mV ST segment depression during the submaximal test was 8.1 +/- 4.5 min. These changes occurred at a rate-pressure product of 15,250 +/- 3,705 and an oxygen uptake of 14.3 +/- 5.9 ml/kg per min, and were significantly (p less than 0.001) lower than values observed during the graded exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

运动试验收缩压和舒张压反应异常对冠心病的诊断价值及其机制

104例患者接受冠脉造影和平板运动试验,评价运动后SBP恢复比和运动中DBP增量对冠心病的诊断价值。SBP恢复比与DBP增量异常的敏感度与特异度分别为59%、52%与96%、92%,而ST段压低标准则分别为71%与84%。高血压病组中三种指标的假阳性率分别为38%、42%与33%。SBP恢复比与EF呈负相关,与SVR呈正相关,提示运动引起的血压反应异常是左心功能受损和SVR增加所致。     

Left ventricular response to exercise in coronary artery disease: relation to myocardial ischaemia and effects of nifedipine

To assess the relationship between left ventricular (LV) responseto exercise and myocardial ischaemia, 40 patients with coronaryartery disease (CAD) and 17 control subjects underwent radionuclideventriculo-graphy at rest and during semiupright exercise. In14 of the 40 patients with CAD, radionuclide exercise studieswere repeated 20 min after 20 mg of sublingual nifedipine. Patientswith CAD had increases in both LV end-diastolic and end-systolicvolumes and no change in ejection fraction during exercise.End-systolic volume increased and ejection fraction decreasedsignificantly more in patients with multivessel disease, exercise-inducedangina and/or ischaemic ST segment depression. Nifedipine reducedangina and ST-segment depression during exercise, attenuatedexercise-induced increase in end-diastolic and end-systolicvolumes and improved eject ion fraction. This study suggests that in patients with CAD, the responseof LV volumes and ejection fraction to exercise is related tothe degree of exercise-induced myocardial ischaemia and nifedipineimproves exercise LV performance     

Left ventricular functional recovery from exercise in normals and patients with coronary heart disease

Little information is available regarding left ventricular (LV) functional recovery from treadmill exercise. Accordingly, we used a recently described ultrasound index of LV function, the isovolumic index (IVI), to assess LV performance before and after exercise in 9 normal middle-aged men and 12 male patients with coronary artery disease (CAD). The IVI was measured at rest and at each minute for at least 10 min after completion of the Bruce protocol; normals had maximal tests and CAD patients had symptom limited studies. At rest the IVI value for normals was 26.2 +/- 2.1 (SD) and it was 43.5 +/- 8.2 for CAD patients (p less than 0.001); isovolumic times were longer in CAD patients (137 +/- 26 vs. 89 +/- 8 ms, p less than 0.001). The rate of recovery from exercise did not differ between normals and CAD patients. We conclude that despite depression of resting LV performance in CAD patients, the time course of functional recovery of the left ventricle from exercise is not different from normal subjects.     

Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.     

Treadmill exercise test in patients with hypertrophic cardiomyopathy with and without coronary artery disease

We studied whether the treadmill exercise test can discriminate between normal and significant narrowing of coronary arteries in patients with hypertrophic cardiomyopathy (HCM) accompanied with chest pain, and we compared the extent of myocardial ischemia during exercise. Thirty one patients with HCM were divided into two groups; 21 with normal coronary arteries and 11 with significant narrowing of coronary arteries. The treadmill exercise test was carried out in both groups. The following parameters were more frequently seen in the group with coronary stenosis. (1) short treadmill time (338, sec vs 542, p less than 0.05). (2) delta SBP less than or equal to 60 mmHg (delta: end point minus rest, 10 cases vs 12, 0.05 less than p less than 0.1). (3) significant delta ST depression (0.17 mV vs 0.05, p less than 0.05). (4) large delta ST/delta HR (3.3 microV.min/beats vs 0.7). delta ST/delta HR greater than or equal to 2.0 was the most useful for differentiating the two groups, and it was 90% in index both sensitivity and specificity for diagnosis of HCM with significant narrowing of the coronary arteries. It was concluded that treadmill exercise induced more severe myocardial ischemia in patients with HCM who had significant narrowing of the coronary arteries than in patients with HCM who had angiographically normal coronary arteries. The delta ST/delta HR was the most useful index for diagnosis of HCM with significant narrowing of the coronary arteries.     

Hypertensive heart disease: relationship of silent ischemia to coronary artery disease and left ventricular hypertrophy

ECG evidence of silent ischemia occurs commonly in patients with systemic hypertension, but its relationship to left ventricular hypertrophy (LVH), large-vessel coronary artery disease (CAD), and neurohumoral factors remains unclear. Accordingly we validated the results of the echocardiographic method used to measure left ventricular (LV) mass in the Soviet Union by comparison with necropsy measurements in 30 patients, and we examined the relationships in 46 men with essential hypertension among ST segment depression during ambulatory monitoring, exercise stress and transesophageal pacing (n = 38), and LV mass, catheterization evidence of CAD (n = 25), and neurohumoral factors (plasma catecholamines and platelet aggregability). Echocardiographic measurements of LV mass by both the Soviet and Penn methods were closely correlated with necropsy values (r = 0.78 and 90, respectively; both p less than 0.001). During ambulatory monitoring from 1 to 17 episodes of greater than or equal to 1 mm ST depression occurred in 26 of 46 (65%) patients with hypertension; ischemia was also provoked by exercise or pacing stress in most but not all of these patients (65% and 80%, respectively). Neither ST depression nor the occurrence of additional episodes of symptomatic angina was related to the presence of coronary obstruction at catheterization; patients with and without ST depression did not differ in age, blood pressure, or LV mass.(ABSTRACT TRUNCATED AT 250 WORDS)     

X syndrome--report of six cases]

Six patients (2 males and 4 females, mean age of 46 years) with X syndrome were reported in this paper. All patients presented with typical exertional angina pectoris. In 4 patients the angina had a variable threshold of onset, it often occurred at rest and occasionally nocturnally. The electrocardiogram during chest pain showed ST segment depression of more than 0.05-0.1 mV in all 6 patients. The treadmill or bicycle ergometer exercise test was positive in 4 cases (ST segment depression > 0.1 mV), equivocal in 1 (ST segment < 0.1 mV) in whom the 201Tl exercise myocardial perfusion scan showed sign of ischemia, and negative in 1 in whom atrial pacing at heart rate of 135 beats/min induced angina and ST segment depression of 0.1-0.15 mV. Echocardiograms and X ray chest films revealed no sign of ventricular hypertrophy or enlargement. The 201Tl exercise myocardial perfusion scan was performed in 5 patients, which showed signs of ischemia in 4 patients and suspected to have ischemia in 1. Left ventriculograms and coronary angiograms were normal in all 6 patients. Ergonovine provoking test (total dose of 0.4 mg) was negative in 5 patients, it was not performed in 1 in whom there was no evidence of coronary artery spasm by angiogram during appearance of electrocardiographic ischemic changes and chest pain. Left ventricular endomyocardial biopsy was performed in 1 patient, which showed significant smooth muscle cell proliferation in the medial layer of a small artery with diameter of 62.5 mu which produced narrowing of the lumen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Positive treadmill stress tests post myocardial infarction in patients with single-vessel coronary disease

To investigate the possibility that patients with single-vessel coronary artery disease (CAD) and recent myocardial infarction (MI) can have ST segment depression on post infarction treadmill testing due to ischemia, we studied 16 such patients who underwent cardiac catheterization and exercise testing after MI. Of the 11 patients with ST segment depression on treadmill testing, 10 failed to increase their ejection fraction and nine had a focal worsening of wall motion during exercise radionuclide ventriculography. Seven of these 11 patients had hypokinesis or normokinesis in the suspected area of infarction. In contrast, four of the five patients without ST segment depression on treadmill stress testing had an increase in ejection fraction with stress which was significantly greater than that seen in patients with ST depression (7.2% vs 0%, p less than 0.05). Short-term follow-up (1.1 years) revealed continued post infarction angina in 10 of the 11 patients with positive treadmill stress tests. Four of these patients underwent either percutaneous transluminal angioplasty or surgery. We conclude that positive post infarction treadmill tests due to exercise-induced ischemia may occur in patients with single-vessel CAD and may be associated with continued angina that requires surgical intervention.     

Exercise performance-based outcomes of medically treated patients with coronary artery disease and profound ST segment depression

OBJECTIVES

We sought to determine the relationship between exercise duration and cardiovascular outcomes in patients with profound (≥2 mm) ST segment depression during exercise treadmill testing (ETT).

BACKGROUND

Patients with stable symptoms but profound ST segment depression during ETT are often referred for a coronary intervention on the basis that presumed severe coronary artery disease (CAD) will lead to unfavorable cardiovascular outcomes, irrespective of symptomatic and functional status. We hypothesized that good exercise tolerance in such patients treated medically is associated with favorable long-term outcomes.

METHODS

We prospectively followed 203 consecutive patients (181 men; mean age 73 years) with known stable CAD and ≥2 mm ST segment depression who are performing ETT according to the Bruce protocol for an average of 41 months. The primary end point was occurrence of myocardial infarction (MI) or death.

RESULTS

Eight (20%) of 40 patients with an initial ETT exercise duration ≤6 min developed MI or died, as compared with five (6%) of 84 patients who exercised between 6 and 9 min and three (3.8%) of 79 patients who exercised ≥9 min (p = 0.01). Compared with patients who exercised ≤6 min, increased ETT duration was significantly associated with a reduced risk of MI/death (6 to 9 min: relative risk [RR] = 0.25, 95% confidence interval [CI] 0.08 to 0.76; >9 min: RR = 0.14, 95% CI 0.04 to 0.53). This protective effect persisted after adjustment for potentially confounding variables. We observed a 23% reduction in MI/death for each additional minute of exercise the patient was able to complete during the index ETT.

CONCLUSIONS

Optimal medical management in stable patients with CAD with profound exercise-induced ST segment depression but good ETT duration is an appropriate alternative to coronary revascularization and is associated with low rates of MI and death.