The significance of hypotension developing during treadmill exercise testing

ST elevation in recovery post exercise with normal coronary arteries

We present the case of a 45-year-old healthy man who successfully completed three stages of the Bruce protocol but developed inferolateral ST segment elevation in the recovery phase. The ECG change was associated with a marked drop in blood pressure. He underwent emergency coronary angiography which revealed normal coronary arteries. It is likely that post-exercise hypotension triggered coronary spasm which caused the ST segment elevation. Alternatively, coronary spasm may have been the primary event, inducing sufficient myocardial ischaemia to cause a marked drop in blood pressure. Exercise tolerance testing is often a reliable test to rule out reversible myocardial ischaemia. While the physician is focused on ischaemic changes or rhythm abnormalities developing during the exercise phase, the recovery period is just as important and requires as much vigilance. Coronary vasospasm can result in significant ST changes and haemodynamic compromise at any point during the test, and the ECG traces can be indistinguishable from a classic ST elevation myocardial infarction, as in the present case.

Value of Exercise ECG for Risk Stratification in Suspected or Known CAD in the Era of Advanced Imaging Technologies

Exercise stress electrocardiography (ExECG) is underutilized as the initial test modality in patients with interpretable electrocardiograms who are able to exercise. Although stress myocardial imaging techniques provide valuable diagnostic and prognostic information, variables derived from ExECG can yield substantial data for risk stratification, either supplementary to imaging variables or without concurrent imaging. In addition to exercise-induced ischemic ST-segment depression, such markers as ST-segment elevation in lead aVR, abnormal heart rate recovery post-exercise, failure to achieve target heart rate, and poor exercise capacity improve risk stratification of ExECG. For example, patients achieving ≥10 metabolic equivalents on ExECG have a very low prevalence of inducible ischemia and an excellent prognosis. In contrast, cardiac imaging techniques add diagnostic and prognostic value in higher-risk populations (e.g., poor functional capacity, diabetes, or chronic kidney disease). Optimal test selection for symptomatic patients with suspected coronary artery disease requires a patient-centered approach factoring in the risk/benefit ratio and cost-effectiveness.

An update on exercise stress testing

Exercise stress testing is the most commonly used noninvasive method to evaluate for coronary artery disease in men and women. Although emphasis has been placed on the diagnostic value of ST-segment depression, the exercise stress test provides other valuable diagnostic and prognostic data, beyond ST-segment depression. The value of these variables, which include exercise capacity, chronotropic response, heart rate recovery, blood pressure response, and the Duke Treadmill Score, are reviewed in this article. In addition, the gender differences seen with these exercise testing variables are reviewed. In this modern era of exercise stress testing, making use of all the information from a stress test and creating a comprehensive stress testing report are recommended in the evaluation of patients with suspected coronary artery disease who undergo exercise stress testing.

Prognostic value of hypotensive blood pressure response during single-stage exercise test on long-term outcome in patients with known or suspected peripheral arterial disease

OBJECTIVE

A decline in systolic blood pressure during exercise is thought to be a sign of severe coronary artery disease. However, no studies have yet examined this effect in patients with known or suspected peripheral arterial disease. Therefore, we investigated the prognostic value of hypotensive blood pressure response after single-stage exercise test on long-term mortality, major adverse cerebrovascular and cardiac events (MACCE) and the effects of statin, beta-blocker and aspirin use in patients with known or suspected peripheral arterial disease.

METHODS

A total of 2022 patients were enrolled in an observational study with a mean follow-up of 5 years. Hypotensive blood pressure response, 4.6% of the total population, was defined as a drop in exercise systolic blood pressure below resting systolic blood pressure.

RESULTS

Our study showed that hypotensive blood pressure response was associated with an increased risk of all-cause mortality [hazard ratio (HR): 1.74, 95% confidence interval (CI): 1.10-2.73] and MACCE (HR: 1.85, 95% CI: 1.14-3.00), independent of other clinical variables. Additionally, after adjustments for clinical risk factors and propensity score, baseline statin use was associated with a reduced risk of all-cause mortality (HR: 0.60, 95% CI: 0.44-0.80). Besides, statin and aspirin use were both also associated with a reduced risk of MACCE (HR: 0.65, 95% CI: 0.47-0.89 and HR: 0.69, 95% CI: 0.53-0.88, respectively).

CONCLUSION

Hypotensive blood pressure response after single-stage treadmill exercise tests in patients with known or suspected peripheral arterial disease was associated with a higher risk for all-cause long-term mortality and MACCE, which might be reduced by statin and aspirin use.

Hypotensive response during dobutamine stress echocardiography in coronary patients: a common event of well-functioning left ventricle

BACKGROUND

Hypotensive response during dobutamine stress echocardiography (DSE) is a common complication, lacking the prognostic significance of hypotension during exercise treadmill test.

HYPOTHESIS

The present study aimed to assess the possible mechanisms of hypotensive response during DSE and to compare it with exercise treadmill test.

METHODS

In all, 91 patients with known coronary artery disease (CAD) underwent both DSE and exercise treadmill test. Dobutamine-induced hypotension was defined as a systolic blood pressure drop > or = 20 mmHg from baseline or from the previous level of infusion.

RESULTS

Twenty-one (23%) patients, 10 of whom also had bradycardia, developed hypotension during dobutamine infusion. Five (5.5%) patients were severely symptomatic and the infusion was stopped prematurely, while in the remaining 16 the addition of atropine allowed the continuation of the test. Patients prone to hypotension were predominantly female (p = 0.0004), had smaller (p = 0.01) and better functioning left ventricles (p = 0.0004), were unlikely to have rest wall motion abnormalities (p = 0.0008) or multivessel CAD (p = 0.02), and had less ischemia (wall motion score difference) (p = 0.03). Hypotension during exercise treadmill test was observed in only one (1%) patient with left main disease.

CONCLUSION

Hypotension during DSE is unrelated to the anatomical or functional extent of CAD and is frequent in the setting of a well-functioning left ventricle. We suppose that vigorous contraction of a small chamber during dobutamine infusion results in an excessive stimulation of cardiac mechanoreceptors that mediate reflex hypotension and bradycardia.

Significance of hypotensive response during dobutamine stress echocardiography

BACKGROUND

In patients undergoing exercise testing a hypotensive response is associated with a poor prognosis. There is limited information regarding the prognostic significance of hypotension during dobutamine stress test. This study investigates the association between a severe hypotensive response during DSE and long-term prognosis.

METHODS

Patients (3381) underwent dobutamine stress echocardiography (DSE). Blood pressure was measured automatically at rest and at the end of every dose-step. Wall motion was scored using a 16-segement, 5-point score. Ischemia was defined by the presence of new wall motion abnormalities. Hypotensive response during DSE was defined as mild (MHR) when systolic blood pressure (SBP) dropped <20 mmHg between rest and peak stress, and severe (SHR) when SBP dropped <20 mmHg. During follow-up all cause mortality and MACE (cardiac death or non-fatal myocardial infarction) were noted.

RESULTS

MHR and SHR occurred in 936 (28%) and 521 (15%) patients, respectively. Independent predictors of SHR were older age, new or worsening wall motion abnormalities and history of hypertension. During follow-up of 4.5 (+/-3.3) years, 920 patients died, of which 555 due to cardiac causes, and 713 patients experienced a MACE. After adjustment for baseline characteristics and DSE results SHR during DSE was independently associated with increased long-term cardiac death (HR: 1.3, 95% CI: 1.03-1.6) and MACE (HR: 1.34, 95% CI: 1.1-1.6), while MHR was not associated with a worse outcome.

CONCLUSIONS

Severe hypotensive response during DSE independently predicts cardiac death and MACE in patients with known or suspected coronary artery disease.

Prognostic value of peak exercise systolic blood pressure on long-term survival after myocardial infarction

This study examined the association between peak exercise systolic blood pressure and other exercise test parameters and the long-term (19-year) survival of 625 patients with myocardial infarction who were original participants of the National Exercise and Heart Disease Project, a 3-year (1976 to 1979) multicenter randomized exercise clinical trial. Results show that low peak exercise systolic blood pressure (< or =140 mm Hg) was associated with increased mortality throughout the 19 years of follow-up, and men with this finding obtained no survival benefit from participating in an exercise program.

Comparison of dobutamine and treadmill exercise echocardiography in inducing ischemia in patients with coronary artery disease

OBJECTIVES

We sought to compare the magnitude of ischemia precipitated by both treadmill exercise and dobutamine stress echocardiography.

BACKGROUND

Although it is alleged that dobutamine stress produces ischemia similar in degree and extent to that produced during treadmill exercise, a direct comparison with treadmill exercise, the most common form of exercise, has not been performed.

METHODS

Eighty-five consecutive patients with known coronary artery disease underwent both stress tests on the same day, in random order.

RESULTS

Sixty-two patients (73%) had positive results on exercise echocardiography compared with 53 (62%) who had positive results on dobutamine stress (p = NS). Of the 53 patients with positive dobutamine test results, wall motion abnormalities appeared after the addition of atropine in 35 patients (66%). During dobutamine infusion, 22 patients (26%) had a hypotensive response that was reversed in 16 by prompt administration of atropine. At peak dobutamine-atropine stress, heart rate was higher than that at peak exercise (p < 0.001), whereas systolic blood pressure and rate-pressure product were higher at peak exercise than at peak dobutamine-atropine stress (p = 0.0001). In the 53 patients with positive results on both tests, peak wall motion score index was greater with treadmill exercise than with dobutamine-atropine infusion ([mean +/- SD] 1.73 +/- 0.45 vs. 1.57 +/- 0.44, p < 0.001).

CONCLUSIONS

Echocardiography immediately after treadmill exercise induces a greater ischemic burden than dobutamine-atropine infusion. In the clinical setting, exercise echocardiography should therefore be chosen over dobutamine echocardiography for diagnosing ischemia, when possible. When dobutamine echocardiography is used as an alternative modality, maximal heart rate should always be achieved by the addition of atropine.

Abnormal systolic blood pressure response during exercise recovery in patients with angina pectoris

OBJECTIVES

This study was conducted to clarify the mechanisms of the abnormal systolic blood pressure response after exercise in patients with angina pectoris.

BACKGROUND

An abnormal systolic blood pressure response in patients with angina pectoris has been observed not only during exercise but also during the recovery period after exercise. However, the mechanisms of this abnormal response during recovery have not been elucidated.

METHODS

Thirty-five patients with angina pectoris and 17 control subjects underwent bicycle ergometric studies after insertion of a Swan-Ganz catheter.

RESULTS

In control subjects, all hemodynamic variables decreased rapidly after exercise. In 7 of the 35 patients, systolic blood pressure increased after exercise. The patients with angina were classified into two groups. In group I (17 patients), changes in systolic blood pressure during recovery were smaller than those in control subjects. In group II (18 patients) recovery of systolic blood pressure was normal. Changes in stroke index from rest to peak exercise were smaller in group I than in group II. Stroke index in both patient groups increased paradoxically during recovery. The increase in systemic vascular resistance index during recovery and the ratio of plasma norepinephrine concentration to cumulative work load were greater in group I than in group II.

CONCLUSIONS

An abnormal systolic blood pressure response after physical exercise in patients with angina pectoris is indicative of severe myocardial ischemia during exercise and may be caused by an increase in stroke volume due to recovery from myocardial ischemia and increased systemic vascular resistance secondary to exaggerated sympathetic nervous activity.

Paradoxic hypotension during dobutamine stress echocardiography: clinical and diagnostic implications

OBJECTIVES

The purpose of this study was to elucidate the prevalence, magnitude and clinical implications of a hypotensive response during dobutamine stress echocardiography.

BACKGROUND

Dobutamine stress echocardiography is an accurate noninvasive method for detecting coronary artery disease. It has been associated with unexpected hypotension in a proportion of patients. Hypotension occurring during exercise testing has been associated with an increased prevalence of multivessel coronary artery disease and a poor prognosis. The clinical significance of hypotension when seen during dobutamine infusion for diagnostic testing is unknown.

METHODS

Clinical characteristics, coronary artery anatomy (n = 41), ventricular function at rest and during dobutamine infusion and prognosis were evaluated in 115 patients experiencing hypotension during dobutamine stress echocardiography and compared with data in 59 nonhypotensive catheterized patients for comparison of coronary anatomy and in 239 nonhypotensive patients for prognostic purposes.

RESULTS

Hypotension occurred in 115 (20%) of 568 consecutive patients studied with dobutamine stress echocardiography. It was gradual in 73 and precipitous in 42 patients. There were no statistical differences among the hypotensive groups and the index group in prevalence or severity of coronary disease or in prognosis during 15 months compared with findings in nonhypotensive patients.

CONCLUSIONS

Hypotension occurs commonly during dobutamine stress echocardiography, and patients with dobutamine-induced hypotension constitute a heterogeneous group. Unlike hypotension occurring with exercise testing, dopamine-induced hypotension is not invariably associated with advanced coronary disease or an adverse prognosis.

Mechanism of exercise-induced hypotension in coronary artery disease

Hypotension during exercise testing has been considered a marker of extensive coronary artery disease (CAD) and poor prognosis. The mechanism of hypotension was examined in 25 CAD patients who developed hypotension during treadmill exercise testing (mean decrease in systolic blood pressure [BP] 33 +/- 13 mm Hg) (group 1) and was compared with the results of 25 CAD patients who had a normal systolic BP response to exercise (mean increase 53 +/- 15 mm Hg) (group 2). The 2 groups were comparable in age, sex, extent of CAD, previous myocardial infarction, left ventricular ejection fraction, history of hypertension and cardiac medications. Exercise heart rate (121 +/- 23 vs 133 +/- 25 beats/min; p = not significant [NS]) and duration (6 +/- 2 vs 7 +/- 3 minutes; p = NS) were comparable. ST-segment depression occurred in 44% of patients in group 1 and in 52% in group 2 (p = NS), and angina during exercise occurred in 60% of both groups. Single-photon emission computed tomographic thallium images were abnormal in 24 patients (96%) in group 1 and in 20 patients (80%) in group 2 (p = NS). Percent thallium abnormality was 19 +/- 12% in group 1, and 18 +/- 14% in group 2 (p = NS), and the severity of thallium abnormality was 710 +/- 510 in group 1, and 510 +/- 500 in group 2 (p = NS). Ischemia involving the inferior/posterior segments was seen in 68% of patients in group 1 and in 60% in group 2 (p = NS). Increased lung thallium uptake was seen in 48% of both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Stable angina pectoris: 2. Cardiac evaluation and diagnostic testing

The examination of a patient with angina pectoris begins with clinical assessment. Certain clinical findings that are present only during angina, such as mitral regurgitation due to ischemia-induced papillary muscle dysfunction, may clarify an otherwise uncertain diagnosis. Electrocardiography is a useful and relatively inexpensive test for detecting evidence of ischemia in patients with suspected angina. The presence of cardiomegaly on the chest roentgenogram has adverse prognostic implications. Exercise stress testing is important in the diagnosis of coronary artery disease and also provides prognostic information. Patients should be classified into high-, intermediate-, or low-risk subsets by noninvasive techniques. Although relatively easy and inexpensive, treadmill exercise stress testing cannot be performed in all patients, and sometimes it will yield equivocal results. In these cases, radionuclide testing (with thallium scintigraphy or radionuclide angiography) can be helpful and also can identify high-risk patients. Some patients will require coronary angiography.

Hypotension during exercise caused by venodilatation

A 54-year-old woman without organic heart disease presented with presyncopal symptoms during work. A decreased cardiac output was demonstrated by haemodynamic measurements during exercise. Treatment with fludrocortisone and ephedrine was initiated with a good haemodynamic and symptomatic result.

Exercise response in young women with mitral valve prolapse

To detect for possible evidence of autonomic nervous system dysfunction, we assessed exercise response in 198 young women with echocardiographically documented MVP. The same test was used to determine whether patients with or without physical symptoms or with various auscultatory findings responded differently. Compared with 105 age- and sex-matched healthy subjects, the MVP patients showed significantly higher mean heart rate, systolic blood pressure, pulse pressure and rate-pressure (double) product, at both rest and exercise; significantly lower mean near-maximal physical working capacity (PWC170); significantly higher incidence of both arrhythmias and nonspecific ST and T wave changes; and a significantly longer mean corrected QT interval. None of these findings was associated with the presence of physical symptoms or with specific auscultatory or echocardiographic findings. These observations strongly suggest an autonomic nervous system imbalance in some young women with MVP, irrespective of whether physical symptoms are present.

Impaired blood pressure response to exercise in patients with coronary artery disease: possible contribution of attenuated reflex vasoconstriction in non-exercising muscles

Eighteen patients with coronary artery disease were divided into two groups according to whether their blood pressure decreased (eight, group 1) or increased (10, group 2) in response to treadmill exercise testing. Age and the extent and distribution of coronary artery disease were similar in the two groups. At rest, blood pressure, pulmonary artery wedge pressure, cardiac index, forearm vascular resistance, and oxygen consumption were similar in the two groups. During supine leg exercise on a bicycle ergometer mean blood pressure increased in group 2 but did not change in group 1. Increases in cardiac index, pulmonary artery wedge pressure, and oxygen consumption during leg exercise were not significantly different in the two groups but forearm vascular resistance increased less in group 1 than in group 2. There was a positive correlation between the magnitude of the change in mean blood pressure and change in forearm vascular resistance during leg exercise. The impaired response of blood pressure to leg exercise in group 1 was not the result of a failure of the cardiac index to increase. The results suggest the possibility that attenuation of reflex vasoconstriction in non-exercising muscles may contribute to the impaired response of blood pressure to exercise in patients with coronary artery disease.

Left ventricular exercise echocardiographic abnormalities in apparently healthy men with exertional hypotension

Of a total of 1,435 healthy untrained asymptomatic individuals referred for a routine periodic checkup, 23 subjects with exertional hypotension on upright bicycle stress testing were identified. All were male. This study assesses by means of echocardiography the responses to exercise of left ventricular (LV) volumes, ejection fraction and segmental LV contractility in these subjects. Exertional hypotension was defined as a decrease in systolic blood pressure to below the resting value at the end of stress test. Supine systolic blood pressure after exercise was significantly greater in the control group than in the study group (179 vs 121 mm Hg, respectively; p less than 0.001); there was no significant intra- or intergroup difference in the resting values. In the study group end-systolic volume was 37 ml at rest and 35 ml after exercise; ejection fraction varied from 65% at rest to 63% after exercise. The sex- and age-matched control group with a normal systolic blood pressure response to exercise showed a shift from 35 to 23 ml and 65 to 77%, respectively (p less than 0.01 and 0.001). Ejection fraction correlated well with radionuclide angiography values. Exertional hypotension was noted after both upright and supine exercise. The pattern of regional wall motion remained unchanged or was hypokinetic in 87% of the subjects; only 13% presented the normally expected hyperkinesia after exercise. This study demonstrates that exertional hypotension is accompanied by an abnormal LV performance.

Exercise-induced hypotension in a male population. Criteria, causes, and prognosis

The objective of this study was to demonstrate the causes, optimal definition, and predictive value of exercise-induced hypotension occurring during treadmill testing. This study included all patients referred for clinical reasons to the Long Beach Veterans Administration Medical Center treadmill laboratory and then followed for a 2-year period for cardiac events. The population consisted of 2,036 patients who underwent testing from April 4, 1984, to May 7, 1987, 131 of whom exhibited exercise-induced hypotension (6.4%). We found that exercise-induced hypotension is usually related to myocardial ischemia or myocardial infarction, is best defined as a drop in systolic blood pressure during exercise below the standing preexercise value, and indicates a significantly increased risk for cardiac events (3.2-fold, p less than 0.005). This increased risk was not found in those having no previous myocardial infarction or no signs or symptoms of ischemia during the exercise test, and the increased risk was also not found in those undergoing a treadmill test within 3 weeks after a myocardial infarction. Exercise-induced hypotension appeared to be reversed by revascularization procedures, but confirmation of a beneficial effect on survival requires a randomized trial. The clinical importance of this study is that we have demonstrated that a drop in systolic blood pressure below standing preexercise values during treadmill testing indicates an increased risk for cardiac events except in certain subsets of patients.

The prognostic value of the exercise test

Numerous investigators have demonstrated that responses to exercise testing enable prediction of the severity of underlying coronary disease and the patient's prognosis. However, exercise testing cannot predict angiographic findings or a poor prognosis with absolute certainty. Because survival can only be improved in specific clinical subsets of patients, it is important to carefully select for catheterization those in whom intervention can improve both quality and quantity of life. To deliver cost-effective health care, an effort has been made to use decision analysis to select those who should undergo cardiac catheterization. Decision analysis depends on reliable information regarding the predictive accuracy of the exercise test. Thus, this review is timely. Recent studies investigating the prognostic value of the exercise test are reviewed in this monograph. Patients include those recovering from a recent myocardial infarction (MI), those with stable coronary heart disease (including studies that have considered coronary angiographic findings, cardiac end points, and/or improved survival with coronary artery bypass surgery), and apparently healthy individuals. From this review, we conclude that silent ischemia induced by exercise testing in apparently healthy men is not as predictive of a poor outcome as once thought. Also, the use of the exercise test for screening is even more misleading than previously appreciated because of the higher rate of false positive results. Review of the 24 available studies of exercise testing in post-MI patients demonstrates that clinical judgment can be used to identify the high-risk patients, and that ST-segment shifts are not as predictive of high risk as an abnormal systolic blood pressure response or a poor exercise capacity. In patients with stable coronary heart disease, studies considering angiographic findings, cardiac events, and the differential outcome of coronary artery bypass surgery as compared with medical therapy have shown the exercise test to have prognostic power. From this perspective, it is obvious that there is much information supporting the use of exercise testing as the first noninvasive step after the history, physical examination, and resting electrocardiogram in the prognostic evaluation of patients with coronary artery disease. It accomplishes both purposes of prognostic testing: to provide information regarding the patient's status, and to help make recommendations for optimal management. The exercise test results help us make reasonable decisions for selection of patients who should undergo coronary angiography-including quality-of-life issues.(ABSTRACT TRUNCATED AT 400 WORDS)

Cost-effectiveness of screening strategies for left main coronary artery disease in patients with stable angina

To define optimal strategies for screening for left main coronary artery disease (LMCAD), the authors evaluated the cost-effectiveness of exercise tolerance testing and cardiac catheterization in patients with mild stable chest pain, such as patients with definite or probable angina in the Coronary Artery Surgery Study registry (prevalence of LMCAD = 9%). Performance characteristics of the exercise test, operative mortality, long-term survival rates, and rates of crossing over to surgical therapy for patients initially managed with medical therapy were derived from pooled literature data; cost estimates were based on local charge data. Strategies using the exercise test to identify candidates for catheterization were associated with longer life expectancies than either the conservative strategy in which patients would be observed or the more aggressive strategy in which all patients would undergo coronary angiography. The most cost-effective option was to screen patients with an exercise test and to perform catheterization in patients with greater than or equal to 2 mm of ST-segment change. Compared with a strategy of catheterization for greater than or equal to 3 mm of ST-segment change only, this strategy increased life expectancy at marginal costs per year of life saved ranging from $11,263 to $18,100 for 40- to 70-year-old patients, respectively, while, compared with a strategy of observation unless symptoms worsened, its incremental cost-effectiveness was $6,510 to $12,428 per year of life saved. Thus, screening patients with stable chest pain syndromes with exercise tests and performing catheterization for patients with greater than or equal to 2 mm of ST-segment change has cost-effectiveness comparable to that of the treatment of moderate diastolic hypertension.

Anatomic and functional significance of a hypotensive response during supine exercise radionuclide ventriculography

The significance of a decline in systolic blood pressure (BP) during supine exercise was examined in 820 patients who underwent both supine exercise gated equilibrium radionuclide ventriculography and coronary angiography. Twenty-seven patients, 3% of the study population, had a decrease in systolic BP at peak exercise of more than 10 mm Hg from the systolic BP at rest. Other indicators of ischemia--angina, ST-segment depression, a decrease in ejection fraction and wall motion abnormality during exercise--were present frequently but not uniformly in these patients. Although most patients had a decline in ejection fraction and a new wall motion abnormality with exercise, 4 patients had an increase in ejection fraction with exercise without any regional wall motion abnormalities. Coronary angiography in the 27 patients with systolic hypotension demonstrated severe coronary artery disease (CAD). Twenty-two patients (81%) had 3-vessel or left main CAD. Twenty of these 22 patients with 3-vessel CAD had at least 2 arteries with 90% or more diameter stenoses. Systolic hypotension during supine exercise radionuclide angiography is infrequent, usually associated with evidence of global and regional left ventricular dysfunction, and a marker of very severe CAD.

Significance of abnormal blood pressure response during exercise-induced myocardial dysfunction after recent acute myocardial infarction

The relation between exercise left ventricular ejection fraction and blood pressure (BP) responses after an acute myocardial infarction (AMI) was investigated. Twenty-eight to 37 days after an uncomplicated AMI, 224 consecutive patients underwent exercise radionuclide angiography in the 40 degrees semisupine position. In 180 patients (group A, 80%), BP increased more than 5 mm Hg every stage; in 44 patients, BP responses were abnormal; in 33 (group B, 15%), BP did not increase during 2 stages; in 11 (group C, 5%), it decreased more than 5 mm Hg after an initial increase. Ejection fraction did not differ significantly among the 3 groups at rest (51 +/- 13 in group A, 50 +/- 18 in group B, 47 +/- 13 in group C [difference not significant]) or at peak exercise (51 +/- 16% in group A, 46 +/- 19% in group B, and 43 +/- 16% in group C, [difference not significant]). Exercise-induced left ventricular failure or hemodynamic decompensation occurred in 22 patients. In these patients, ejection fraction at rest was 44 +/- 19% and decreased to 35 +/- 16% (p less than 0.05) with exercise. Only 9 of these patients (41%) had abnormal BP responses, with the other 13 (59%) showing a normal BP responses. The The 35 patients with abnormal BP responses in the absence of hemodynamic decompensation were asymptomatic, terminating exercise because of fatigue. The ejection fraction at rest and during exercise in these patients was similar to that in patients with normal BP responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective evaluation of a clinical and exercise-test model for the prediction of left main coronary artery disease

In a multivariate logistic regression analysis of data from 508 patients, only two clinical factors, age and typicality of pain, were independently significant predictors of left main coronary artery disease. The resulting multivariate equation was prospectively applied to another 370 patients to derive pre-exercise-test (ETT) probabilities of left main coronary artery disease, and these pre-ETT probabilities were combined with literature-derived likelihood ratios for various ETT findings to derive post-ETT probabilities. This model, which can be displayed in simple graphic form, accurately predicted the probability of left main coronary artery disease when prospectively evaluated in this independent validation set of patients. The likelihood of left main coronary artery disease was 16% when the ETT increased the probability, and 4% when it decreased the probability (p less than 0.001). While 48% of patients had mid-range (5-15%) probabilities of left main coronary artery disease before the ETT, only 24% fell into this range of probabilities after the ETT (p less than 0.0001), as ETT results moved patients into higher and lower probability ranges. Thus, probability of left main coronary artery disease can be calculated from clinical and ETT data with this model. These estimated pre- and post-ETT probabilities of left main coronary artery disease may aid in the selection of patients for noninvasive testing or for cardiac catheterization.

Determinants of abnormal blood pressure response to exercise in coronary artery disease

This study assessed the determinants of exercise-induced abnormal systolic blood pressure (BP) response in 127 patients with documented coronary artery disease (CAD) who underwent exercise thallium-201 scintigraphy. Three types of systolic BP response to exercise were identified: an increase by more than 20 mm Hg (group I, n = 74); an increase by 20 mm Hg or less (group II, n = 36); and a decrease of at least 10 mm Hg (group III, n = 17). The 3 groups were not significantly different in age, gender or medications. The number of segments with perfusion defects was significantly higher in groups II and III than group I (group III, 2.9 +/- 1.5; group II, 2.9 +/- 2.1; and group I, 1.8 +/- 1.4, p = 0.009). Prior myocardial infarction, abnormal left ventricular ejection fraction, and multivessel CAD were more common in group III than in groups I and II. Stepwise discriminant analysis of 15 relevant clinical, angiographic and exercise scintigraphic descriptors showed that the number of thallium perfusion defects, abnormal LV ejection fraction at rest and multivessel CAD to be important predictors of hypotensive BP response. Multivariate analysis, however, showed that the number of thallium perfusion defects was the only important predictor of the hypotensive response. Thus, it is the functional significance of CAD assessed by the extent of thallium perfusion abnormalities rather than the extent of CAD or left ventricular dysfunction at rest that determines the systolic BP response to exercise.

Prediction of mortality in hospital survivors of myocardial infarction. Comparison of predischarge exercise testing and radionuclide ventriculography at rest

The relative merits of resting ejection fraction measured by radionuclide angiography and predischarge exercise stress testing were compared for predicting prognosis in hospital survivors of myocardial infarction. Two hundred and fourteen survivors of myocardial infarction out of 338 consecutive patients with acute myocardial infarction were studied over a 14 month period. Hospital mortality was 13% (45 of 338) whereas 19 additional patients out of 214 died in the subsequent year (9%). High, intermediate, and low risk groups could be identified by left ventricular ejection fraction measurement. Mortality was 33% for nine patients with an ejection fraction less than 20%, 19% for 58 patients with an ejection fraction between 20% and 39%, and 3% for 147 patients with an ejection fraction greater than 40%. Mortality was high (23%) in 47 patients who were unable to perform the stress test because of heart failure (19) or other limitations (28). The patients could be stratified further into intermediate and low risk groups according to the increase in systolic blood pressure during exercise: six deaths occurred in 46 patients with a blood pressure increase of less than 30 mm Hg and two deaths occurred in 121 patients with an increase greater than or equal to 30 mm Hg. Maximum workload, angina, ST changes, and ventricular arrhythmias were less predictive than blood pressure changes. It is concluded that the prognostic value of radionuclide angiography at rest and of symptom limited exercise testing is similar. The latter investigation should be the method of choice since it provides more specific information for patient management.

Simultaneous recording of continuous arterial pressure, heart rate, and ST segment in ambulant patients with stable angina pectoris

Simultaneous and accurate recording of arterial blood pressure and ST segment changes is fraught with technical difficulties. We have developed a new system to enable accurate reproduction of the electrocardiogram and intra-arterial blood pressure, using a transducer/perfusion unit conventionally used to study hypertensive subjects, linked to a frequency modulated tape recorder. Detailed methods of digital analysis have been developed to process the data. This system has been used to study 22 patients with arteriographically proven severe obstructive coronary artery disease who suffered frequent attacks of angina. Control data from quantified dynamic exercise in the laboratory were used for comparison with the effects of normal daily activities outside the hospital and to test the hypothesis that "double product" (heart rate X systolic blood pressure) is relevant to the onset of angina in such patients. The most important finding was that both angina and asymptomatic episodes of ST segment depression were invariably accompanied by an increase in heart rate, whereas there was considerable variation in blood pressure changes ranging from an increase to a substantial fall. This suggests that heart rate changes are more important in determining ischaemic episodes than blood pressure. Furthermore, the "double product" was not reproducible during repeated episodes of angina and asymptomatic ischaemia and did not appear to have an important role in the pathogenesis of intermittent myocardial ischaemia in this group of patients.

Prognostic and predictive value of exertional hypotension in suspected coronary heart disease

The prognostic and predictive value of exertional hypotension was assessed in 1,241 patients having treadmill maximal exercise testing, coronary arteriography, and follow-up averaging 5.4 years. Medically treated patients with coronary artery disease (CAD) with exertional hypotension had poorer survival than did those without such hypotension; however, maximum systolic pressure during exercise was a more powerful predictor of survival. Patients with exertional hypotension had more extensive CAD and more left ventricular (LV) dysfunction than did patients who had an increase in blood pressure with exertion; these findings probably account for the impaired survival. However, exertional hypotension, was an insensitive indicator of significant left main coronary artery stenosis, 3-vessel disease, or severe resting LV dysfunction.

Diagnostic accuracy of exercise ECG lead systems in clinical subsets of women

The diagnostic accuracy of 14-lead exercise electrocardiography was evaluated in 112 women who had no history of myocardial infarction and underwent coronary angiography. The sensitivity of ST-segment displacement of 0.1 mV or more in any of 14 ECG leads was 0.79 for coronary artery stenosis of at least 70%; the specificity was 0.66. Results were similar using bipolar ECG leads CC5 and CM5 or 11 standard ECG leads. The ST-segment shifts that occurred only during exercise were associated with a 77% false-positive rate (10 of 13). Downsloping ST-segment depression did not provide more diagnostic information than horizontal ST-segment depression in the three clinical subsets of women. In women with typical angina pectoris, ST-segment depression of at least 0.15 mV for 0.08 second after the J point or a final treadmill time less than 360 seconds was predictive of proximal left or multivessel coronary artery disease. In the women with probable angina or nonspecific chest pain, this finding was not of diagnostic value. ST-segment elevation of 0.1 mV or more in leads V1-2 or a VL predicted proximal stenosis of at lest 80% in the left anterior descending coronary artery in all six women with typical angina pectoris. Maximal exercise testing in women with typical angina provides important diagnostic information when 11 standard ECG leads are recorded. In women with probable angina or nonspecific chest pain, diagnostic exercise testing is less useful and bipolar leads CC5 and CM5 are sufficient for most clinical purposes.

Decrease in systolic blood pressure during exercise testing: reproducibility, response to coronary bypass surgery and prognostic significance

To investigate the reproducibility and prognostic significance of an exercise-induced decrease in systolic blood pressure, 47 patients were identified who manifested such a reduction below the pre-exercise standing level in a consecutive series of 436 patients who underwent treadmill exercise testing and cardiac catheterization during a 3 year period. The prevalence of this abnormal finding was 11 percent in the total group but 21 percent in the 124 patients with three vessel or left main coronary artery disease. Patients with an exercise-induced reduction in systolic blood pressure were more likely to be male, have typical angina pectoris with class III or IV functional limitation and to have had a prior myocardial infarction than were patients without this finding (p less than 0.05). Although no complications occurred during the exercise test of these 47 patients, the majority had severe ischemic responses and 14 (30 percent) showed complex repetitive ventricular arrhythmias. Of the 47 patients, 24 (group 1a) received medical treatment and 23 (group 1b) underwent coronary bypass surgery. On repeat exercise testing in 42 patients, a decrease in systolic blood pressure during exercise was consistently present in group 1a (17 of 20) but entirely absent (0 of 22) in group 1b (p less than 0.001). The mean treadmill time, peak heart rate and systolic blood pressure were not significantly different in the initial and on repeat exercise tests in patients in group 1a; however, in patients in group 1b, all of these variables were significantly higher in the repeat test (p less than 0.001). At a mean follow-up time of 37 months, the total cardiac mortality rate was 8 percent (2 of 24) in group 1a and 4 percent (1 of 23) in group 1b. It is concluded that a decrease in systolic blood pressure during exercise testing is highly reproducible and appears to be reversed by coronary bypass surgery.

Diagnostic quantification of CASS (coronary artery surgery study) clinical and exercise test results in determining presence and extent of coronary artery disease. A multivariate approach

Multivariate linear discriminant function analysis on maximal exercise treadmill and angiographic data from 500 men with definite angina, 584 men with probable angina and 267 men with nonspecific chest pain identified independent predictors of presence and extent of coronary disease. We used the discriminant function to develop a clinical risk index and a clinical and exercise risk index for each patient subset. Probability curves were generated to predict the presence and extent of coronary disease. In definite angina cases, exercise testing provided more diagnostic information than clinical data alone. However, in the 10% of cases with the smallest risk indexes, half of the patients had coronary disease and one-quarter had multivessel disease. In men with probable angina, exercise testing added substantially more diagnostic information than clinical data. The probability of multivessel disease was reduced to less than 10% for 30% of patients with probable angina, an important diagnostic contribution. Exercise testing in men with nonspecific chest pain was of limited value because disease prevalence was already low.

Labile hypertension and jogging: new diagnostic tool or spurious discovery?

A labile hypertensive black man reviews his own personal history of hypertension, based on intensive self-study. The evidence suggests that aerobic isotonic exercise (jogging) depresses labile pressure values, forcing them down to near basal levels and preventing a rise to previous blood pressure levels for several hours.

Abnormal blood pressure response and marked ischemic ST-segment depression as predictors of severe coronary artery disease

The usefulness of an abnormal blood pressure response and a marked ischemic ST-segment depression during exercise testing as predictors of severe coronary artery disease was assessed in 378 consecutive patients who had a maximal symptom-limited exercise test before coronary arteriography. An abnormal blood pressure response occurred in 90 patients. The sensitivity of this response for three-vessel or left main disease was 38.6%, the specificity 87.4% and the predictive value 70%. A marked ischemic ST-segment abnormality (MIST) appeared in 85 patients. The sensitivity of MIST for three-vessel or left main disease was 38.6%, the specificity 89.8% and the predictive value 74.1%. One hundred thirty-eight patients had either an abnormal blood pressure response or a marked ST-segment change. The sensitivity of either response for three-vessel or left main disease was 56.4%, the specificity 78.6%, and the predictive value 66.7%. Exercise duration and ejection fraction were not significantly different in patients with normal or abnormal blood pressure. We conclude that abnormal blood pressure and marked ischemic ST-segment depression during exercise testing are helpful in identifying a subset of patients with advanced coronary artery disease. The physiologic mechanism for these responses is probably exercise-induced ischemia.

Syncope after running

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