Thallium-201 myocardial imaging in young asymptomatic subjects with "ischaemic" changes in exercise electrocardiogram.

In order to assess the significance of a positive electrocardiographic response to exercise test in 10 asymptomatic subjects with normal resting ECG, a myocardial perfusion scanning with Thallium-201 at rest and during exercise was performed. The following ECG tests were also performed on these subjects: forced hyperventilation, exercise test after nitroglycerin (TNG), exercise test after propranolol. Myocardial perfusion scans did not reveal any defect at rest nor during exercise. Hyperventilation determined abnormalities of ventricular repolarization in all subjects. TNG did not improve the response to exercise test and even decreased the ischemic threshold. After propranolol the electrocardiographic response to exercise became normal in 9 cases, while in 1 subject the ST depressions were impressively reduced. All subjects had a follow-up of 14 to 91 months. During this period none presented symptoms suggesting a coronary disease. This study suggests that combined evaluation of Thallium myocardial perfusion imaging during exercise and exercise ECG test after TNG is most useful in differentiating ischemic from nonischemic exercise ST depressions in asymptomatic population.     

The effects of oral propranolol, digoxin and combination therapy on the resting and exercise electrocardiogram.

The effects of propranolol, digoxin and combination therapy (/D) on the resting and exercise ECG were studied in ten normal subjects and 20 patients with coronary artery disease (CAD) given a sequence of oral placebo, propranolol, P/D, digoxin and placebo, for two week periods. Digoxin produced a significant decrease in T-wave amplitude and often resulted in ST segment depression in the resting ECG. Propranolol, digoxin, and P/D tended to decrease the QTc interval and prolong the PR interval. However, CAD patients were more sensitive to PR prolongation than normals while receiving propranolol or digoxin alone. Propranolol therapy did not significantly affect the ST segment of the exercise ECG in the normal subjects or the CAD patients without an ischemic control exercise ECG. By contrast, 50 per cent of the normal subjects developed "false-positive" ischemic ST segment responses to exercise while receiving digoxin of P/D and three of eight CAD patients without ischemic control exercise ST segments had a similar response to digoxin or P/D. In 12 CAD patients with ischemic control exercise ST segments, propranolol did not affect the amount of ST segment depression at the onset of angina or the maximum amount of ST segment depression. Digoxin or P/D both uniformly increased the maximum amount of ST segment depression which was greater with digoxin than P/D. However, the maximum heart rate on P/D was significantly reduced as compared to that on digoxin. It is concluded that (1) CAD patients are more sensitive to propranolol or digoxin-induced AV block than normals, (2) propranolol does not change the magnitude of ischemic exercise ST segment depression, (3) digoxin increases ischemic exercise ST segment depression and results in a high incidence of false-positive exercise tests, and (4) the addition of propranolol to digoxin attenuates the effects of digoxin on the exercise ST segment.     

Alterations of ventricular repolarization at rest, in young asymptomatic subjects. Diagnostic and predictive value of non-invasive methods]

In 34 asymptomatic subjects, aged 16 to 39 years, with clearcut abnormalities of ventricular repolarization on resting electrocardiogram, a forced hyperventilation and maximal exercise test were performed. The stress test was repeated, using the same protocol, after sublingual administration of nitroglycerin (0.3 mg) and of i.v. injection of propranolol (0.1 mg/Kg). In 24 subjects an echocardiogram was recorded: a mitral valve prolapse was present in 6 cases, while in 11 cases minor abnormalities were found. The response to exercise test was positive in 50% of cases. After nitroglycerin the ischemic threshold increased in 7 subjects while it remained unchanged or even lowered in 10 cases. In subjects with a negative stress test nitroglycerin did not produce any important electrocardiographic variations both at rest and during exercise. After propranolol injection the repolarization abnormalities on resting electrocardiogram disappeared or decreased in 23 subjects. The drug increased the exercise tolerance in 4 cases; in other 12 subjects the electrocardiographic response to stress testing became normal. During the follow-up period coronary events occurred in 3 cases; in all of them nitroglycerin had induced an increase of ischemic threshold. Our study suggests that the evaluation of the exercise ischemic threshold after nitroglycerin can be useful in order to identify subjects at high coronary risk.     

Assessment of Diagnostic Value of Dipyridamole Testing in Angina Pectoris

Summary: In order to assess the diagnostic value of dipyridamole (D) testing, we studied the responses of 34 patients with chest pain and 10 normal subjects. Blood pressure and 12-lead ECG were recorded during and after intravenous infusion of 0.6 mg/kg dipyridamole for 10 minutes. Coronary arteriography and maximal or symptom-limited exercise tests were performed in the 34 patients with chest pain. During infusion 13 patients presented ischemic ST changes and 5 with anginal pain only. The latter group had normal coronary arteries. Among the 13 patients with ischemic ST changes, 7 had at least two critical coronary stenoses and the remaining 6 had no coronary lesions. Dipyridamole tests showed poor sensitivity (44%) and specificity (39%) with respect to coronary arteriography. The relatively high number of positive responses in subjects with normal coronary arteries indicates that the coronary steal phenomenon is not the sole cause of “ischemic” response to the drug. Indirect indexes of myocardial oxygen consumption were higher in patients with a positive response to drug infusion than in those with a negative response; however the value of rate-pressure product at infusion end never reached that observed at ischemic threshold during exercise testing in the same patient. This suggests that neither can oxygen consumption increase be considered as entirely responsible for ischemic response to dipyridamole. In conclusion dipyridamole test cannot be proposed for predicting critical coronary stenoses.     

Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of stress and long-term ECG in the diagnosis of silent myocardial ischemia in patients with coronary heart disease

Symptomatic and asymptomatic myocardial ischemia during exercise testing and during daily activities (ST-segment analysis on 24-h Holter ECG) was studied in 109 patients with stable angina pectoris and proven coronary artery disease (coronary stenoses greater than 70%) (group I) and in 20 patients with angiographically normal coronary arteries or minimal changes (group II). During exercise testing, 94/109 (86.2%) group I patients and 6/20 (30%) group II patients showed ST-segment depression greater than or equal to 0.1 mV. During Holter ECG, transient ST-segment depression (greater than or equal to 0.1 mV; greater than or equal to 1 min) was observed in 76/109 (69.7%) group I patients and in 5/20 (25%) group II patients; all patients with positive Holter ECG also had a positive exercise tests result. Heart rate and exercise duration at the onset of ischemia during stress testing were useful parameters to estimate the incidence of ischemic episodes during Holter ECG. Patients with asymptomatic positive exercise tests showed a significantly higher percentage of asymptomatic ischemic episodes during Holter ECG than patients with a symptomatic positive exercise test (89% vs. 68% asymptomatic ischemic episodes; p less than 0.001). Therefore, in patients with coronary artery disease and stable angina pectoris, the exercise test provides information also about the activity of ischemic heart disease during daily activities.     

Effect of nitroglycerin on exercise-induced abnormalities of left ventricular regional function and ejection fraction in coronary artery disease. Assessment by radionuclide clineagiography in symptomatic and asymptomatic patients.

The effects of nitroglycerin (TNG) on exercise-induced abnormalities of left ventricular wall motion and ejection fraction are unknown in symptomatic and asymptomatic patients with coronary artery disease (CAD). In the present investigation radionuclide cineangiographic studies were performed in 47 patients with CAD (14 without angina during exercise) and in 25 normal subjects. All CAD patients, including those without symptoms, demonstrated regional wall motion abnormalities during exercise. In all patients, ejection fraction (EF) also responded abnormally to exercise: EF decreased from 48% at rest to 36% during exercise (P less than 0.001). EF increased in all normal subjects from an average of 58% at rest to 71% during exercise (P less than 0.001). In all CAD patients TNG reduced exercise-induced regional wall abnormalities and increased EF attained during exercise from an average of 36 to 48% (P less than 0.001). EF in normal subjects was unchanged by TNG. Thus, exercise can cause abnormalities in left ventricular regional function and ejection fraction in patients with or without symptoms; these abnormalities can be mitigated by prophylactic TNG.     

Individual variability in symptoms, ischemic threshold and cardiovascular efficiency during exercise testing in patients with effort angina

This study assessed both group and individual variability of ECG exercise stress test in patients with effort angina. Forty-five untreated patients with typical effort angina, without evidence of spontaneous angina, with a positive exercise stress test (ST depression greater than 0.2 mV) and angiographically documented coronary artery disease were studied. Four multistage exercise stress tests were performed, two in the morning and two in the afternoon, on two consecutive days. Forty-four patients completed the protocol for a total of 176 exercise stress tests. For each exercise stress test the following parameters were analyzed: time to 0.15 mV ST segment depression (time to ischemia); rate-pressure product at ischemia (ischemic threshold); slope and intercept of the linear regression between rate-pressure product and time of exercise. Silent effort ischemia was largely prevalent: 21 patients (48%) experienced chest pain in all four tests, but only seven showed a consistent time relationship between pain and ECG changes. Symptomatic patients did not appear different from the asymptomatic ones in terms of clinical and angiographic data. When group data were analyzed for each parameter the four exercise stress tests appeared reproducible. In contrast, when individual variability of each parameter was computed as the percentage difference between range (maximum--minimum) and maximal value obtained in the series of four exercise stress tests, a large variability was detected. Variability of time to ischemia, was 27.2 +/- 17.4%. This resulted from a random combination of variability in ischemic threshold (19.1 +/- 9.2%), slope (28.4 +/- 12.8%) and intercept (22.7 +/- 10%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Normal electrocardiographic waveform characteristics during treadmill exercise testing.

Forty asymptomatic male patients at low risk for cardiovascular disease completed maximal treadmill testing. Electrocardiograms from leads CC5, CM5, V5, Yh and Z were recorded across multiple pretest, exercise and recovery conditions. ECG waveforms were subsequently digitized, averaged and processed to provide Q-, R-, S- and T-wave amplitudes, ST-segment means and slopes, and QS- and RT-interval durations. Average R-wave amplitude increased during early exercise and then dramatically decreased to maximum effort. Average S-wave amplitude became greater as exercise progressed. Average J junction was slightly positive before exercise, became negative during exercise (except lead Z) and returned to zero after exercise. The ST-segment slope increased dramatically with progressive exercise. The response of T-wave amplitude, RT and QS intervals are also described. Separately, 22 asymptomatic male subjects each completed two maximal treadmill tests 2 weeks apart. ECG data acquisition and processing were similar to those noted above. Pooled, within-subject estimates of variability were computed for the ECG leads, ECG measurements and protocol conditions. These variability estimates are useful for interpreting ECG responses to exercise testing.     

Prevalence and significance of an abnormal exercise ECG in asymptomatic males. Outcome of thallium myocardial scintigraphy

During a 3-year period 2500 asymptomatic male aviators were screened routinely for coronary artery disease by maximal bicycle exercise testing. In 55 cases (2.1%) the exercise ECG was abnormal (40 subjects exhibited ST depression, 14 ventricular ectopic activity and in one subject both abnormalities were observed). Further non-invasive studies (Thallium scintigraphy, echocardiography and ambulatory ECG monitoring for arrhythmias) identified nine out of the 55 aviators (16%, 95% CL = 7-26%) with an abnormal exercise test as having cardiac disease. We conclude that standard exercise ECG by itself is a poor predictor of coronary artery disease in asymptomatic subjects because of too many false-positives when the pre-test likelihood of disease is low. Therefore, exercise electrocardiography cannot be recommended as the single routine screening test for coronary artery disease in such individuals.     

Changes in transthoracic electrical impedance during submaximal treadmill exercise in patients with ischemic heart disease--A preliminary report.

Twenty normal subjects and 32 patients with ischemic heart disease (IHD) were subjected to submaximal treadmill exercise. The mean transthoracic electrical impedance (TEI) was measured with a tetrapolar lead system and the changes were correlated to the extent of ST depression observed on an on-line digital computer. Six subjects of pre-excitation syndrome with "false" ST depression were also studied. The normal subjects did not show a significant change of TEI during exercise. The patients with IHD showed a steady and significant decrease in TEI, correlating with the extent of ST depression. Recovery was slow after the cessation of exercise. The subjects with false ST changes showed no decrease of TEI. The changes were more profound in subjects who developed anginal pain during the test. These findings are attributed to an increase in the thoracic blood volume and pulmonary extravascular water due to transient left ventricular dysfunction in angina.     

ST-segment isolation and quantification as a means of improving diagnostic accuracy in treadmill stress testing.

A new method of ST-segment analysis utilizing computer-analytic techniques has been employed in treadmill exercise testing, with the aim of enhancing diagnostic sensitivity and specificity. One hundred thirty-three individuals were studied, including 62 normal subjects (Group I), 29 patients with coronary disease and clear, "ischemic" ST-segment responses to exercise testing (Group II), and 42 patients with coronary disease but normal or nondiagnostic exercise tests (Group III). The techniques used included: computer averaging, to minimize motion artifact and baseline drift; a means of isolating the ST-segment from the T-wave and quantifying ST-amplitude and slope (the isolated ST integral, IST); and the relating of the IST to a given heart rate, thus taking cognizance of the dependency of ST-depression on heart rate and level of exercise. These methods resulted in a test specificity exceeding 90 per cent and a sensitivity of over 85 per cent. Further evidence of the improved sensitivity achieved using these techniques included a 79 per cent (33 of 42) recognition of abnormalities in Group III, patients having normal or nondiagnostic visually interpreted treadmill stress tests (i.e., no flat or downsloping ST-segments of 1 mm. or greater). Moreover, 15 of 29 patients in Group II (52 per cent) manifested abnormal IST's before development of a typical "ischemic" ST, and in 17 patients (59 per cent), the IST continued to remain positive after disappearance of the characteristic flat or downsloping ST-segment. It is concluded that this type of computation analysis adds appreciable diagnostic sensitivity and specificity to treadmill stress testing.     

Observer accuracy and confirmation of the important role of abnormal ST/T time course behavior in the evaluation of stress electrocardiograms.

Routine exercise electrocardiography has been criticized for yielding too many so-called "false-positive" results. Recent studies in our institution indicate that evaluation of the time course behavior of ST segment and T wave (ST/T) changes after cessation of exercise differentiates ischemic from non-ischemic ("false-positive") stress electrocardiograms (SEs). Our method of assessing time course behavior is clarified. The principal aim of this study was to determine the accuracy of experienced observers in making this differentiation. Records of consecutive patients undergoing coronary arteriography over a 2 year period were reviewed and 30 with SEs judged positive for ischemia by the widely accepted ST/T configurational criteria alone were selected at random for the investigation. Sixteen subjects had normal coronary angiograms and had therefore previously been regarded as having false-positive SEs. Fourteen patients had at least one significantly (> 70%) stenosed coronary artery which was our yardstick for ruling that true myocardial ischemia, due to epicardial coronary artery disease (CAD), was present. Five observers, familiar with post-exercise ST/T time course patterns, independently and "blindly" analyzed all 30 configurationally abnormal SEs. Observers were informed only of the patient's age and sex; they were thus unaware of symptoms, exercise variables, coronary anatomy and the number of patients in the 2 groups. The observer consensus for ischemia of SEs using time course analysis was: total test accuracy 87%, sensitivity 79%, specificity 94%, positive predictive value 92% and negative predictive value 83%. Because all 30 patients had ST/T abnormalities, results of the sample for ischemia based on configurational criteria alone were sensitivity 100%, specificity 0% and positive predictive value 47%. We concluded that time course analysis plays a crucial role in evaluating SEs and that exercise electrocardiography remains a safe, cost-effective and reliable method of screening many asymptomatic, as well as symptomatic, subjects for CAD.     

Heart rate adjustment of ST-segment depression for reduction of false positive electrocardiographic responses to exercise in asymptomatic men screened for coronary artery disease

The ability of heart rate (HR) correction of exercise-induced ST-segment depression (the delta ST/HR index) to reduce the number of false positive exercise electrocardiograms during initial screening for occult coronary artery disease (CAD) was examined in active, asymptomatic men from the Army Reserve. Among 606 consecutive men given treadmill tests, 62 asymptomatic subjects with normal results on resting electrocardiograms but abnormal outcomes on standard exercise electrocardiograms underwent rest and exercise radionuclide cineangiography, and the 10 subjects with abnormal radionuclide findings then underwent coronary angiography. A previously established delta ST/HR index less than 1.6 microV/beat/min correctly identified 34 of 52 subjects (65%) who, despite abnormal standard exercise electrocardiographic findings, had no rest or exercise radionuclide abnormalities. A delta ST/HR index greater than or equal to 1.6 microV/beta/min detected 7 of 7 subjects with abnormal radionuclide cineangiograms who had CAD at cardiac catheterization, but also identified 2 of 3 subjects with an abnormal radionuclide test who had no CAD. In contrast to the 7 of 62 subjects (11%) with abnormal standard exercise test criteria who had radionuclide and angiographic evidence of CAD, a delta ST/HR index partition of 1.6 microV/beat/min separated subjects into subgroups with 0% (0 of 35) vs 26% (7 of 27) prevalences of CAD by serial diagnostic evaluation (p less than 0.01). Thus, among asymptomatic subjects with abnormal electrocardiographic responses to exercise, simple HR correction of the magnitude of ST-segment depression reduced by 56% the number of subjects with standard exercise test criteria leading to referral for additional diagnostic evaluation, without loss of sensitivity for angiographically proven CAD and with accurate negative predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transient myocardial ischemia during daily life in patients with syndrome X

Nineteen patients with syndrome X (typical exertional angina, positive exercise test response [at least 0.1 mV of ST-segment depression], no evidence of coronary spasm and angiographically normal coronary arteries) underwent continuous 48-hour electrocardiographic (ECG) monitoring during unrestricted daily life. Fifty-eight ischemic episodes of at least 0.1 mV of ST-segment depression were observed in the same ECG leads that showed ST depression during stress testing: 28 (48%) were accompanied by anginal pain and 30 (52%) were asymptomatic. No significant differences were found between painful and silent ST-segment depression with regard to the number of episodes, their temporal distribution, magnitude, duration or heart rate (HR) at onset of ST-segment depression. In the minute preceding ischemic ST shifts, HR did not change in 33% of episodes or increased by less than 10 beats/min in 28%. HR at onset of ST depression was significantly lower during ambulatory ECG monitoring than during exercise testing (98 ± 18 vs 117 ± 18 beats/min, p < 0.01). During ambulatory monitoring, 85 episodes of sinus tachycardia (exceeding by 10 to 80 beats/min the HR that triggered ischemia during exercise testing) occurred in the absence of angina or ST-segment shifts. The results of this study suggest that in patients with syndrome X, (1) myocardial ischemia frequently develops during daily life; (2) silent ischemia is an important component of this syndrome; and (3) increased oxygen demand in the presence of impaired coronary vasodilatory capacity is not the only cause of myocardial ischemia. Active mechanisms that transiently reduce coronary flow may act and explain occurrence of angina at rest and with minimal exertion.     

Value of exercise testing to evaluate the indication for surgery in asymptomatic patients with valvular aortic stenosis

BACKGROUND AND AIMS OF THE STUDY: The study aim was to assess the value of exercise stress testing in identifying asymptomatic patients with moderate or severe valvular aortic stenosis (AS). These patients generally develop symptoms during follow up, and require valvular replacement surgery (VRS) at one to three years after single symptom-limited exercise stress testing. Limited data are available on predictors of outcome in asymptomatic patients with valvular AS. A single symptom-limited exercise stress test might offer more precise risk stratification of patients referred for cardiological evaluation. METHODS: The safety and diagnostic accuracy of exercise testing to predict symptom development and need for surgery was assessed prospectively in 30 asymptomatic patients (mean age 62+/-14 years) with valvular AS. Twenty patients had moderate AS (mean Doppler gradient 30-49 mmHg), and 10 severe AS (gradient > or =50 mmHg). Patients underwent a symptom-limited maximal exercise test with upright bicycle ergometry. There were no complications during and after exercise testing. All patients were followed up for at least 36 months. RESULTS: Ergometry was abnormal in 18 patients (60%); two patients had a fall in systolic blood pressure, one patient had a fall in systolic blood pressure with angina and ECG signs of myocardial ischemia, one had angina and ECG signs of myocardial ischemia, three patients had ECG signs of myocardial ischemia without symptoms, and 11 had dyspnea at low workload. During the following 12 months all patients with a normal exercise test remained asymptomatic (negative predictive value 100%). Ten of the 18 patients with abnormal exercise test experienced symptoms and required VRS, but eight did not (positive predictive value 55%). After 36 months, only two of 12 patients with a normal exercise test developed symptoms and required VRS (negative predictive value 83%); among subjects with abnormal exercise test, four of 18 required VRS. At three years after exercise testing, 10 patients with a normal exercise stress test and four with an abnormal test did not require VRS as they remained asymptomatic (positive predictive value 78%). There was no statistically significant difference in valvular aortic area, maximal and mean gradient between patients with normal and abnormal exercise tests. CONCLUSION: Exercise stress testing may be performed safely in asymptomatic patients with moderate or severe valvular AS. Tests which meet criteria for normal patients allow physicians confidently to postpone VRS and to suggest a simple, cost-effective method of follow up in such cases. An abnormal test may reveal symptoms or identify a population for closer follow up.     

"Silent" myocardial ischemia during and after exercise testing in patients with coronary artery disease

Although many patients with coronary artery disease (CAD) have a positive exercise test without pain, the frequency and significance of this "silent" ischemia is unclear. Therefore, we studied 122 consecutive clinically stable patients with angiographically defined CAD (greater than 75 per cent luminal stenosis) and a positive exercise test. Seventy-eight patients had pain or anginal equivalent during or after a positive exercise test; 44 did not, including 32 (26 per cent) with no symptoms at all. Patients were evaluated as to age, sex, prior myocardial infarction, congestive failure, hypertension, diabetes mellitus, and digoxin or propranolol therapy--in addition to anginal symptoms before, during, or after the exercise itself. Extent of CAD, presence of collaterals, and left ventricular ejection fraction were also determined. All exercise tests were evaluated for evidence of ST-T abnormalities or prior infarction on the control ECG as well as peak heart rate during exercise and post-exercise degree of ST segment depression. There were no significant differences between patients with and without exercise-induced pain in regard to any of the clinical and angiographic features noted above, demonstrating that "silent" myocardial ischemia during or after exercise testing is not uncommon and is not readily attributable to any obvious clinical or catheterization findings. Further studies are necessary to determine if patients with evidence of "silent" myocardial ischemia are especially prone to sudden death.     

Usefulness of early exercise testing after non-Q-wave myocardial infarction in predicting prognosis

The value of an early symptom-limited maximal exercise test in predicting coronary anatomy, left ventricular ejection fraction and hemodynamics was assessed prospectively in 64 patients after an acute non-Q-wave myocardial infarction (MI). Exercise tests and cardiac catheterization were performed at a median of 6 and 7 days, respectively, after non-Q MI. Forty-one percent of the patients had a negative exercise test response (no angina, less than 1 mm of ST depression and normal blood pressure responses). Twenty-five percent had a positive response (1 to 1.9 mm of ST depression or angina); 34% had a "strongly positive" exercise test response (at least 2 mm of ST depression or abnormal blood pressure responses). A negative response predicted the absence of 3-vessel disease (at least 70% stenosis) or critical stenoses (at least 90% stenosis) involving major coronary arteries (negative predictive accuracy 92%), whereas a strongly positive response predicted their presence (positive predictive value 77%, specificity 88%). Cardiac index and mean pulmonary artery wedge pressure did not vary significantly among the 3 exercise groups, whereas left ventricular ejection fraction was slightly higher in the exercise test group with a positive response (p less than 0.025). Thus, in patients who have had a non-Q MI, early exercise testing can be used to predict the extent and severity of coronary artery disease, and the decision to perform coronary angiography should be guided by the exercise test results.     

Influence of R wave analysis upon diagnostic accuracy of exercise testing in women.

Exercise electrocardiography in women with chest pain is associated with a high incidence of false positive ST segment depression. The recent observation that changes in R wave amplitude during exercise can also be used diagnostically may improve the value of stress testing in women. The results of 12 lead treadmill exercise and coronary angiography were reviewed in 62 women, mean age 51 years, presenting with "angina" without previous myocardial infarction. These were compared with exercise results in 14 healthy asymptomatic volunteers with a mean age of 26 years. In addition to conventional ST analysis, R wave amplitude changes during exercise, measured in leads II, III, a VF, and V4 to 6, were examined. While the sensitivity and specificity of ST and R wave changes were similar at about 67%, their combined interpretation was helpful. If both ST and R wave criteria were negative the predictive accuracy for normal coronary angiography was 94% (17/18). Alternatively, in tests showing both ST depression and an abnormal R wave response, coronary angiography was always abnormal (13/13). None of the normal volunteers developed ST segment depression and 93% (13/14) had a normal R wave response. If both were positive, however, coronary angiography was always abnormal (13/13). Although stress test interpretation in women is difficult, R wave analysis is a useful adjunct to ST change and can improve the predictive accuracy of the test in a significant number of patients.     

Changes in regional wall contractility induced by effort in women with normal coronary angiography --report of a clinical case]

The diagnosis of coronary artery disease in women has been thought to be more difficult than in men, owing to the lower overall prevalence of disease in women, as well as more subtle clinical presentations and unspecific changes in ST segment. The authors report a clinical case of a 61-year old woman, with low cardiovascular risk and history of atypical chest pain and a positive treadmill exercise test on the inferior leads. She did an exercise echocardiogram that revealed severe hypokinesis on the anterior wall and septum with late normalization. The patient was submitted to a coronary angiography that revealed normal arteries. An echocardiogram with hyperventilation was later performed and showed the same ischemic changes as exercise did, on the inferior leads but no regional wall motions abnormalities occurred. The patient is currently asymptomatic under calcium antagonist treatment.