INTRODUCTION — Stress testing in patients with known or suspected coronary heart disease (CHD) provides information about prognosis as well as diagnosis. This topic will provide an overview of the utility of stress testing for estimation of prognosis as a guide to management in patients with known or suspected CHD. The methodology, indications, and contraindications of stress testing are discussed separately.
●(See "Exercise ECG testing: Performing the test and interpreting the ECG results".)
●(See "Stress testing for the diagnosis of obstructive coronary heart disease".)
●(See "Risk stratification after non-ST elevation acute coronary syndrome", section on 'Stress testing'.)
●(See "Risk stratification after acute ST-elevation myocardial infarction", section on 'Stress testing'.)
INDICATIONS FOR STRESS TESTING FOR PROGNOSIS — All indications for performing a stress test for the diagnosis of CHD are also indications for performing a stress test for risk stratification and prognosis. Common indications for performing a stress test include:
●Symptoms suggestive of myocardial ischemia
●Acute chest pain after acute coronary syndrome (ACS) has been excluded
●Recent ACS with no or incomplete revascularization
●Worsening symptoms with known CHD
●Preoperative evaluation for high-risk noncardiac surgery
The indications for stress testing are discussed in detail separately. (See "Selecting the optimal cardiac stress test", section on 'Indications for stress testing'.)
EXERCISE ECG — Exercise stress testing provides more information about prognosis than pharmacologic stress testing. Exercise capacity is one of the strongest determinants of prognosis, and predicts mortality and cardiovascular events, particularly in older adults [1-4]. The heart rate and blood pressure responses to exercise stress also provide prognostic information. Finally, evidence of the presence and extent of stress-induced myocardial ischemia also provides important prognostic information. Among patients who undergo exercise stress, a number of variables, either alone or in combination, are associated with an increased risk of an adverse outcome in patients with CHD [2,5-12]. These include:
●Poor exercise capacity
●Exercise-induced angina, particularly that which is exercise-limiting or occurs at a low workload
●Low peak systolic blood pressure (<130 mmHg) or a fall in systolic blood pressure below baseline during exercise [12]
●Low peak heart rate (ie, chronotropic incompetence) (see 'Heart rate response to exercise' below)
●Slow recovery of heart rate after exercise
There are also a number of ECG findings during exercise that indicate inducible myocardial ischemia and convey a worse prognosis:
●ECG evidence of inducible ischemia (≥1 mm of downsloping or flat ST segment depression during exercise or recovery)
●≥2 mm of ischemic ST depression at a low workload (stage 2 or less or ≤130 beats per minute)
●Early onset (stage 1) or prolonged duration (>5 minutes) of ST depression
●Multiple leads (>5) with ST depression
●ST segment elevation (in leads without pathologic Q waves and not in aVR)
●Ventricular couplets or tachycardia at a low workload or during recovery
The prognosis after exercise ECG testing may be better predicted with the use of treadmill scores that take into account multiple variables. (See 'Duke treadmill score' below.)
Exercise capacity — Patients with poor exercise capacity are at increased cardiovascular risk, while those with excellent exercise capacity (a measure of fitness) are at reduced risk [13]. The importance of exercise capacity was illustrated in a report of 6213 consecutive men referred for exercise testing who were then followed for a mean of 6.2 years [2]. After adjustment for age, peak exercise capacity, measured in metabolic equivalents (METs), was the strongest predictor of mortality among men, whether or not they had cardiovascular disease. One MET is defined as the resting oxygen uptake in a sitting position (3.5 mL O2 uptake/kg per minute), and can be estimated from any of the commonly used exercise protocols. For each 1 MET increase in exercise capacity, there was a 12 percent improvement in survival. The achieved exercise capacity and workload have also been shown to be predictive in older adult populations [3,4].
Flat or downsloping ST depression — A positive exercise ECG test is defined as ≥1 mm horizontal (flat) or a downsloping ST segment depression measured at 80 milliseconds after the end of the QRS complex, as recommended by the ACC/AHA guidelines [14]. In addition to providing diagnostic information [15], ST segment depression provides prognostic information, especially when considered in the context of the level of exercise that leads to ST depression. (See "Exercise ECG testing: Performing the test and interpreting the ECG results", section on 'ST segment depression'.)
Flat or downsloping ST depression can occur during exercise and during recovery and has prognostic significance at both time periods.
●In one study of 1472 patients who underwent exercise stress testing and coronary angiography, patients who developed ≥1 mm ST depression in stage 1 or 2 of the Bruce protocol (table 1) or at heart rates less than 120 beats per minute had a poor prognosis (12-month survival of less than 85 percent) and a high probability of significant left main (25 percent) or three vessel disease (more than 60 percent) [7]. In contrast, the ability to exercise into stage 4 (>10 METs) or to achieve a maximal heart rate greater than 160 beats per minute with <1 mm ST depression was associated with an excellent prognosis (12-month survival more than 99 percent).
●Among 4083 medically-treated patients with stable angina enrolled in the Coronary Artery Surgery Study (CASS) Registry, patients with ≥1 mm exercise-induced ST depression and final stage ≤1 of the Bruce protocol (table 1) were at high risk with an average annual mortality rate of approximately 5 percent per year [5]. In contrast, patients who had <1 mm ST depression and final exercise stage ≥3 on the Bruce protocol were at low risk with an annual mortality of less than 1 percent per year.
Heart rate response to exercise — An impaired heart rate response to exercise, known as chronotropic incompetence, is generally defined as failure to achieve 85 percent of the age-predicted maximum heart rate in the absence of medications known to blunt the heart rate response to exercise (eg, beta blockers or non-dihydropyridine calcium channel blockers). While there are some conflicting data, chronotropic incompetence is generally thought to be predictive of all-cause mortality and CHD risk [11,16-18].
●In a prospective cohort of 2953 patients, 11 percent failed to achieve at least 85 percent of the age-predicted maximal heart rate [17] and had a significant increase in mortality at two years (absolute increase 4 percent, adjusted relative risk 1.84) (figure 1).
●Similar findings were noted in a report of 3221 patients undergoing treadmill exercise echocardiography in which 495 patients (15 percent) failed to achieve at least 85 percent of the age-predicted maximal heart rate [18]. At a median follow-up of 3.2 years, these patients had significant increases in all-cause and cardiac mortality compared with patients with >85 percent of age-predicted maximal heart rate (adjusted risk 1.5 and 2.1).
Heart rate recovery after exercise — Delayed return of the heart rate to the normal range after exercise, probably a reflection of decreased vagal reactivation, provides important prognostic information among patients with known CAD as well as among all patients referred for exercise testing. The definitions of abnormal heart rate recovery (HRR) have varied in different studies from ≤12 to ≤18 beats per minute at one minute [19-22] to ≤22 to ≤42 beats per minute at two minutes [23-25]. Late HRR (five minutes after the cessation of exercise) has also been defined and investigated [26].
●In a study of 2428 patients referred for exercise stress testing, abnormal HRR (defined as ≤12 beats per minute) while the patient was exercising lightly during the one minute "cool-down phase" was associated with an increase in overall mortality at six-year follow-up (figure 2) [19]. In a follow-up study of 9454 subjects at the same institution, mortality at five years was independently predicted by both abnormal HRR and an intermediate or high Duke treadmill score (8 versus 2 percent in those with a low score) [20]. The predictive value of abnormal HRR was independent of the angiographic severity of coronary disease [21]. (See 'Duke treadmill score' below.)
●In a systematic review which included four studies and 2428 patients with documented pre-existing CAD referred for exercise stress testing, abnormal HRR (defined variably as ≤12 to 21 beats per minute) was associated with greater than fivefold risk of mortality [27].
●In patients who undergo exercise echocardiography requiring them to lie down immediately (rather than having a cool down phase) after exercise cessation, abnormal HRR (≤18 beats per minute) independently predicts increased mortality [22].
●Late HRR at five minutes post-exercise appears to provide additional prognostic information beyond that acquired with abnormal HRR at one minute. In a cohort of 2082 patients who underwent exercise testing and were followed for an average of 10 years, patients with impaired late HRR at five minutes had significantly higher all-cause mortality [26].
Exertional hypotension — Exertional hypotension, defined as a fall in systolic blood pressure below that measured standing at rest, is fairly rare during exercise testing but when present suggests a poor prognosis, likely due to underlying heart failure or severe multivessel coronary disease [12]. In patients with exercise-induced ischemia or prior myocardial infarction (MI), exertional hypotension is associated with an increased risk for new cardiac events. Other causes of exercise-induced hypotension include fixed cardiac output (as seen with stenotic valvular heart disease or hypertrophic cardiomyopathy), volume depletion, anemia, or certain drugs (such as vasodilators). The exercise test should stop when exertional hypotension is detected.
Ventricular arrhythmias — Exercise-induced ventricular ectopy occurs in 7 to 20 percent of patients undergoing exercise ECG testing for known or suspected coronary disease [28-32]. (See "Premature ventricular complexes: Treatment and prognosis", section on 'Exercise-induced'.)
Most studies have noted an association between exercise-induced ventricular arrhythmia and increased mortality [28-32]. However, it remains uncertain whether ventricular arrhythmia is an independent risk factor or a marker for more severe underlying disease.
●In a study of 1293 patients with suspected CHD who underwent an exercise test within six weeks of coronary angiography, the development of premature ventricular contraction (PVCs) was more common in patients with three-vessel disease, reduced left ventricular (LV) function, segmental wall motion abnormalities, and a greater degree of ST segment depression during exercise [30]. PVCs added independent prognostic value to noninvasive evaluation but provided no independent information once the results of coronary angiography were known. There was no relationship between PVCs and survival in patients without significant CHD.
In a clinical cohort of over 29,000 patients referred for symptom-limited exercise testing, frequent ventricular ectopy occurred in 7 percent of persons only during exercise and in 3 percent only during recovery [28]. Development of frequent ventricular ectopy during recovery (but not during exercise) was associated with increased cardiovascular mortality (propensity-matched HR 1.5 and 1.1, respectively, compared with those without ectopy). Similar results were reported in a subsequent study [33].
Atrial arrhythmias — Atrial arrhythmias also occur during exercise [34,35]. In a report of 5375 patients with known or suspected CHD, premature atrial complex (also referred to a premature atrial beat, premature supraventricular complex, or premature supraventricular beat) occurred in 24 percent, supraventricular tachycardia in 3.4 percent, and atrial fibrillation/flutter in 0.8 percent [34]. In contrast to exercise-induced ventricular arrhythmias, the development of atrial arrhythmias during exercise was not predictive of long-term rates of cardiac death or revascularization after adjustment for clinical and exercise variables.
Exercise-induced LBBB — The development of transient left bundle branch block (LBBB) during exercise testing may also be a marker of increased risk. In a review of 17,277 exercise tests, transient LBBB was noted in 70 (0.4 percent) [36]. The development of LBBB was an independent predictor of death and major cardiac events at four years (adjusted relative risk 2.78).
PROGNOSTIC SCORES
Duke treadmill score — A validated treadmill score from Duke University is based upon data from 2758 consecutive patients seen from 1969 through 1980 with a median age of 49 who had chest pain and underwent both exercise treadmill testing and coronary angiography [8].
The Duke treadmill score (DTS) is calculated from three exercise parameters, where:
●Exercise time is based on minutes completed on Bruce protocol (or equivalent to Bruce protocol)
●ST deviation is the maximum deviation (in mm) compared with baseline
●Angina score: 0 for no pain, 1 for nonlimiting pain, 2 for exercise limiting pain
DTS = Exercise time (minutes) - (5 x ST deviation) - (4 x angina score)
Patients are classified as low, moderate, or high risk according to the score:
●Low risk – score ≥+5
●Moderate risk – score from -10 to +4
●High risk – score ≤-11
Subsequent reports have confirmed the utility of the Duke treadmill score in different groups [37-41]. As an example, the following findings were noted in the different risk groups in an analysis of the original Duke cohort of 2758 medically treated patients [38]:
●Among the 36 percent of patients categorized as low risk, 60 percent had no coronary stenosis ≥75 percent, 16 percent had single vessel disease, and 9 percent had three vessel or left main disease; five-year survival was above 97 percent.
●Among the 9 percent of patients categorized as high risk, 74 percent had three vessel or left main disease, and five-year survival was 65 percent.
●Among the 55 percent of patients categorized as moderate risk, the frequency of three vessel or left main disease (31 percent) and five-year survival (90 percent) were intermediate between the other two groups.
Within each risk class, the prognosis was better in women than men [39]. The Duke treadmill score also appears to perform better in women than men for excluding disease. In a study which included 976 women and 2249 men with chest pain and suspected CHD, fewer low-risk women had any coronary artery with ≥75 percent stenosis (19 versus 47 percent in men) or three vessel or left main disease (3.5 versus 11.4 percent) [39].
The Duke treadmill score added independent prognostic information to that provided by clinical data, coronary anatomy, and LV function. As an example, subset analysis in the original study revealed that among patients with three-vessel disease, those with an abnormal exercise score had a five-year survival rate of 67 percent compared with 93 percent for those with a normal exercise score [8].
Other risk scores — Other treadmill scores have also been devised. One model used exercise testing data from 4083 patients from the Coronary Artery Surgery Study (CASS) registry who were treated medically and followed prospectively [5,42,43]. The presence of significant (≥1 mm) exercise-induced ST depression, the stage of exercise completed, and the extent of LV dysfunction were important determinants of one-year mortality and of the likelihood of three-vessel or left main disease. (See 'Flat or downsloping ST depression' above.)
The Cleveland Clinic nomogram-illustrated model was developed from the results of ECG exercise testing in 30,000 patients referred for suspected coronary heart disease, all of whom had normal baseline ECGs [43]. It was validated in a separate group of over 5000 patients. The Cleveland Clinic model was better able to predict all-cause mortality over three years than the Duke score. However, the Cleveland Clinic model is more difficult to use due to the inclusion of multiple clinical variables such as age, sex, and presence of risk factors, as well as more exercise variables.
RADIONUCLIDE MYOCARDIAL PERFUSION IMAGING — Combined myocardial perfusion and function results from stress radionuclide myocardial perfusion imaging (rMPI) can distinguish patients at high risk (more than 5 percent annual mortality rate) from those at intermediate risk (1 to 5 percent annual mortality rate) or low risk (less than 1 percent annual mortality rate) [44].
The prognostic usefulness of pharmacologic stress rMPI is comparable to that of exercise stress rMPI [1,45]. In a meta-analysis that combined data from 14,918 patients in 24 different studies, exercise stress rMPI and pharmacologic stress rMPI were comparable in their ability to risk-stratify patients [1]. The following discussion will include studies of rMPI that involved both exercise stress testing and pharmacologic stress agents.
Normal rMPI — A normal rMPI has been reported in multiple studies to be associated with low risk of future cardiac events (less than 1 percent per year) [46-54]. As one example of the predictive value of a normal rMPI result, among 5183 consecutive patients with known or suspected CHD who underwent stress rMPI and were followed for an average of 1.8 years, patients with a normal scan (57 percent of patients) had a low risk for cardiac death or MI (≤0.5 and ≤0.3 percent per year, respectively) (figure 3) [46].
The relatively benign prognosis of a normal rMPI scan persists even in patients with a significantly abnormal exercise ECG test or angiographically significant coronary artery disease [47-49,51,55]. In a study of 4649 patients with known or suspected CHD who had an intermediate risk Duke treadmill score (-10 to 4) and a normal or near-normal rMPI, the seven-year survival from cardiovascular death was 99 percent and the seven-year survival from cardiovascular death or MI was 97 percent [49]. (See 'Duke treadmill score' above.)
Patients with known CHD, a high-risk Duke treadmill score, diabetes, chronic kidney disease, and older age have poor outcomes despite a normal scan. The magnitude of these relationships was illustrated in a review of 7376 consecutive patients with a normal exercise or adenosine rMPI [56]. An 80-year-old man with diabetes and known CHD had a relatively high rate of cardiac death or MI at two years (4.9 percent), while a 50-year-old woman without diabetes or known CHD was at minimal risk (0.1 percent).
Abnormal rMPI — High-risk features on rMPI predicting an increased risk of cardiac events include [44,46,47,57-60]:
●Extensive ischemia
●Ischemia in more than one coronary artery territory
●Ischemia in multiple segments
●LVEF <45 percent
●Large fixed defects
●Transient or persistent LV cavity dilatation [61,62]
As one example of the predictive value of an abnormal rMPI result, among 5183 consecutive patients with known or suspected CHD who underwent stress rMPI and were followed for an average of 1.8 years, patients with normal, mildly abnormal, moderately abnormal, or severely abnormal perfusion defects had progressively higher annual cardiac death rates (0.5, 2.7, 2.9, and 4.2 percent, respectively) (figure 3) [46]. Similar findings have subsequently been reported for stress rMPI using regadenoson as the vasodilator [63].
The risk of an abnormal rMPI varies along with the presence or absence of clinical factors [50,64-66]. In a study that incorporated clinical risk factors (older age, diabetes, resting heart rate, dyspnea as a presenting symptom) and findings on rMPI (percent myocardium that was ischemic), patients with a normal adenosine rMPI had a cardiac mortality rate that varied from 0.4 to 5.3 percent per year in patients with a low and high prognostic score, respectively [64,65]. Similar risk stratification was seen among patients with a moderate to severely abnormal adenosine rMPI, in whom annual cardiac mortality varied from 3.9 to 7.6 percent per year in patients with a low and high prognostic score, respectively. (See 'Duke treadmill score' above.)
STRESS ECHOCARDIOGRAPHY
Exercise echocardiography — Exercise echocardiography provides independent prognostic information that is incremental to clinical, rest echocardiographic, and exercise ECG characteristics [67]. Of all exercise ECG and exercise echocardiographic variables, exercise capacity (ie, workload) and exercise wall motion score index had the strongest association with outcome, with a direct linear relationship between higher numbers of wall motion abnormalities and adverse cardiac events [67]. The incremental prognostic value of exercise echocardiography has also been demonstrated in older adults (≥65 years of age), in patients with diabetes mellitus, and in patients after coronary artery bypass surgery [68-70]. The predictive value of exercise echocardiography is enhanced by combining echocardiographic findings with other exercise test data [71-73].
A normal exercise echocardiogram identifies patients at low short-term cardiac risk [71,72,74]. In a report of 1325 patients with a normal stress echocardiogram, the one- and three-year cardiac event-free survival rates were 99 and 97 percent, respectively [72]. Similar findings were noted in a meta-analysis [74]. Event-free survival after a normal exercise echocardiogram in patients with known or suspected CHD was 98 percent at 33 months, with MI or cardiac death of only 0.54 percent per year. In a study of 4004 patients with interpretable ECGs who underwent stress treadmill echocardiography with no chest pain or ischemic ECG changes during the test (ie, normal exercise stress test result), ischemia was identified by echocardiography in 17 percent of patients [75]. The five-year mortality and major cardiac event rates were 6 and 4 percent in patients without ischemia and 12 and 10 percent in those with ischemia.
Dobutamine stress echocardiography — Dobutamine stress echocardiography provides independent prognostic information concerning possible future cardiac events that is incremental to clinical, rest echocardiographic, and exercise ECG characteristics [73,76-86]. The prognosis varies with the presence, severity, and extent of the induced ischemia and the heart rate at onset of myocardial ischemia (or ischemic threshold). Ischemia occurring at less than 60 percent of age-predicted maximal heart rate identified patients at highest risk for postoperative cardiac events.
In a review of 7333 consecutive patients referred for known or suspected CHD in whom pharmacologic stress echocardiography was performed and follow up to 200 months, overall survival was significantly lower in those with a positive test (59 versus 81 percent), with an estimated mortality of less than 1 percent per year in patients with a negative test [73]. The predictive value was additive to clinical variables and resting echocardiographic wall motion abnormalities.
Dobutamine stress echocardiography is predictive of events in patients with or without resting LV systolic dysfunction [87,88]. ST elevation during dobutamine stress echocardiography has also been associated with a higher risk of future cardiac adverse events [89].
In a study of 3156 patients who underwent dobutamine stress echocardiography and were followed for up to nine years, the number of abnormal territories at peak stress and the type of wall motion abnormality (ischemia or scar as defined by wall motion abnormalities occurring only during exercise or being present at rest, respectively) were independent predictors of cardiac events (figure 4A-B) [80].
Combination with Duke treadmill score — At a given Duke treadmill score on exercise ECG testing, the prognosis can be further stratified by the findings on concurrently performed exercise echocardiography or radionuclide myocardial perfusion imaging [49,71] and by a clinical determination of risk [50]. (See 'Normal rMPI' above.)
The combined utility of the Duke treadmill score and exercise echocardiography was illustrated in a study of 5375 patients with known or suspected CHD [71]. At a mean follow-up of 5.5 years, the following findings were noted:
●Among patients with a low-risk Duke treadmill score, the yearly mortality in those with a normal rest echocardiographic study, or evidence of disease in a single territory, or in multiple territories, was 0.7, 1.8, and 3 percent, respectively.
●Among patients with a moderate-risk Duke treadmill score, the yearly mortality in the three echocardiographic groups was 2.4, 3.7, and 7 percent, respectively.
●Among patients with a high-risk Duke treadmill score, the yearly mortality in the three echocardiographic groups was 4.6, 5, and 12 percent, respectively.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Chronic coronary syndrome" and "Society guideline links: Multimodality cardiovascular imaging appropriate use criteria" and "Society guideline links: Stress testing and cardiopulmonary exercise testing".)
SUMMARY AND RECOMMENDATIONS
●Stress testing provides important prognostic information in patients with known or suspected coronary heart disease. (See 'Indications for stress testing for prognosis' above and "Selecting the optimal cardiac stress test", section on 'Indications for stress testing'.)
●Exercise stress testing provides more information about prognosis than pharmacologic stress testing. Exercise electrocardiogram (ECG) testing is the preferred method of stress testing in most patients. Exercise capacity is one of the most important determinants of prognosis. (See 'Exercise capacity' above.)
●Exercise-induced ST depression during exercise or recovery also has prognostic significance. (See 'Flat or downsloping ST depression' above.)
●Heart rate responses to exercise stress also provide prognostic information, especially if the predicted exercise heart rate cannot be achieved or the heart rate does not promptly recover from peak levels after exercise. (See 'Heart rate response to exercise' above and 'Heart rate recovery after exercise' above.)
●Stress myocardial imaging using either radionuclide perfusion or echocardiography provides incremental prognostic information over clinical characteristics and exercise testing results. (See 'Radionuclide myocardial perfusion imaging' above and 'Stress echocardiography' above.)
●The Duke treadmill score, which uses three exercise parameters (exercise time, maximum ST segment deviation, and presence of angina), is useful for stratifying patients into low-, moderate-, or high-risk categories for future cardiovascular events. (See 'Duke treadmill score' above.)
1 : Comparison of risk stratification with pharmacologic and exercise stress myocardial perfusion imaging: a meta-analysis.
2 : Exercise capacity and mortality among men referred for exercise testing.
3 : Prognostic value of treadmill exercise testing in elderly persons.
4 : The prognostic value of exercise testing in elderly men.
5 : Prognostic importance of a clinical profile and exercise test in medically treated patients with coronary artery disease.
6 : Noninvasive screening criteria for enhanced 4-year survival after aortocoronary bypass surgery.
7 : The role of the exercise test in the evaluation of patients for ischemic heart disease.
8 : Exercise treadmill score for predicting prognosis in coronary artery disease.
9 : Veterans Administration Cooperative Study of medical versus surgical treatment for stable angina--progress report. Section 8. Prognostic value of baseline exercise tests.
10 : Prognostic implications of results from exercise testing in patients with chronic stable angina pectoris treated with metoprolol or verapamil. A report from the Angina Prognosis Study In Stockholm (APSIS).
11 : Impaired heart rate response to graded exercise. Prognostic implications of chronotropic incompetence in the Framingham Heart Study.
12 : Exercise-induced hypotension in a male population. Criteria, causes, and prognosis.
13 : Prognostic value of exercise capacity in patients with coronary artery disease: the FIT (Henry Ford ExercIse Testing) project.
14 : ACC/AHA 2002 guideline update for exercise testing: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines).
15 : Exercise-induced ST depression in the diagnosis of coronary artery disease. A meta-analysis.
16 : Association of chronotropic incompetence with echocardiographic ischemia and prognosis.
17 : Impaired chronotropic response to exercise stress testing as a predictor of mortality.
18 : Prognostic significance of impairment of heart rate response to exercise: impact of left ventricular function and myocardial ischemia.
19 : Heart-rate recovery immediately after exercise as a predictor of mortality.
20 : Heart rate recovery and treadmill exercise score as predictors of mortality in patients referred for exercise ECG.
21 : Heart rate recovery after exercise is a predictor of mortality, independent of the angiographic severity of coronary disease.
22 : Heart rate recovery immediately after treadmill exercise and left ventricular systolic dysfunction as predictors of mortality: the case of stress echocardiography.
23 : Heart rate recovery: validation and methodologic issues.
24 : Heart rate recovery after submaximal exercise testing as a predictor of mortality in a cardiovascularly healthy cohort.
25 : Enhanced risk assessment in asymptomatic individuals with exercise testing and Framingham risk scores.
26 : Prognostic value of late heart rate recovery after treadmill exercise.
27 : The prognostic value of heart rate recovery in patients with coronary artery disease: A systematic review and meta-analysis.
28 : Frequent ventricular ectopy after exercise as a predictor of death.
29 : Predictive implications of ventricular premature contractions associated with treadmill stress testing.
30 : Prognostic value of ventricular arrhythmias associated with treadmill exercise testing in patients studied with cardiac catheterization for suspected ischemic heart disease.
31 : Significance of exercise-induced ventricular arrhythmia in stable coronary artery disease: a coronary artery surgery study project.
32 : Functional and prognostic significance of exercise-induced ventricular arrhythmias in patients with suspected coronary artery disease.
33 : Ventricular arrhythmias during clinical treadmill testing and prognosis.
34 : The prognostic significance of exercise-induced atrial arrhythmias.
35 : Exercise stress testing for exposure of cardiac arrhythmia.
36 : Prognostic significance of exercise-induced left bundle-branch block.
37 : Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease.
38 : Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups.
39 : Value of exercise treadmill testing in women.
40 : Prognostic value of a treadmill exercise score in symptomatic patients with nonspecific ST-T abnormalities on resting ECG.
41 : Differential risk reclassification improvement by exercise testing and myocardial perfusion imaging in patients with suspected and known coronary artery disease.
42 : Prediction of cardiovascular death in men undergoing noninvasive evaluation for coronary artery disease.
43 : An externally validated model for predicting long-term survival after exercise treadmill testing in patients with suspected coronary artery disease and a normal electrocardiogram.
44 : Principal uses of myocardial perfusion scintigraphy in the management of patients with known or suspected coronary artery disease.
45 : Prognostic value of gated myocardial perfusion SPECT.
46 : Incremental prognostic value of myocardial perfusion single photon emission computed tomography for the prediction of cardiac death: differential stratification for risk of cardiac death and myocardial infarction.
47 : Long-term additive prognostic value of thallium-201 myocardial perfusion imaging over clinical and exercise stress test in low to intermediate risk patients : study in 1137 patients with 6-year follow-up.
48 : Prognostic value of a normal exercise myocardial perfusion imaging study in patients with angiographically significant coronary artery disease.
49 : Long-term outcome of patients with intermediate-risk exercise electrocardiograms who do not have myocardial perfusion defects on radionuclide imaging.
50 : Utility of myocardial perfusion imaging in patients with low-risk treadmill scores.
51 : Prognostic implications of normal exercise SPECT thallium images in patients with strongly positive exercise electrocardiograms.
52 : One-year prognosis of patients with normal planar or single-photon emission computed tomographic technetium 99m-labeled sestamibi exercise imaging.
53 : Prognostic value of thallium-201 myocardial perfusion imaging. A diagnostic tool comes of age.
54 : Long-term (10 years) prognostic value of a normal thallium-201 myocardial exercise scintigraphy in patients with coronary artery disease documented by angiography.
55 : Prognostic value of normal exercise and adenosine (99m)Tc-tetrofosmin SPECT imaging: results from the multicenter registry of 4,728 patients.
56 : Determinants of risk and its temporal variation in patients with normal stress myocardial perfusion scans: what is the warranty period of a normal scan?
57 : Prognostic importance of scintigraphic left ventricular cavity dilation during intravenous dipyridamole technetium-99m sestamibi myocardial tomographic imaging in predicting coronary events.
58 : Prognostic importance of thallium uptake by the lungs during exercise in coronary artery disease.
59 : Significance of increased lung thallium uptake during adenosine thallium-201 scintigraphy.
60 : Prognostic value of lung sestamibi uptake in myocardial perfusion imaging of patients with known or suspected coronary artery disease.
61 : The prognostic value of non-perfusion variables obtained during vasodilator stress myocardial perfusion imaging.
62 : Predictors of high-risk coronary artery disease in subjects with normal SPECT myocardial perfusion imaging.
63 : The prognostic value of regadenoson myocardial perfusion imaging.
64 : A prognostic score for prediction of cardiac mortality risk after adenosine stress myocardial perfusion scintigraphy.
65 : Quantitative instruments for predicting risk ... and benefit.
66 : Prediction of 14-year outcomes in patients with a limited exercise capacity: Utility of dobutamine myocardial perfusion imaging in a high-risk population.
67 : Prognostic value of exercise echocardiography in 5,798 patients: is there a gender difference?
68 : Prognostic value of exercise echocardiography in 2,632 patients>or = 65 years of age.
69 : Prognostic stratification of diabetic patients by exercise echocardiography.
70 : Prognostic value of exercise echocardiography in patients after coronary artery bypass surgery.
71 : Prediction of mortality by exercise echocardiography: a strategy for combination with the duke treadmill score.
72 : Outcome after normal exercise echocardiography and predictors of subsequent cardiac events: follow-up of 1,325 patients.
73 : Stress echo results predict mortality: a large-scale multicenter prospective international study.
74 : The prognostic value of normal exercise myocardial perfusion imaging and exercise echocardiography: a meta-analysis.
75 : Prediction of mortality and major cardiac events by exercise echocardiography in patients with normal exercise electrocardiographic testing.
76 : Optimal use of dobutamine stress for the detection and evaluation of coronary artery disease: combination with echocardiography or scintigraphy, or both?
77 : Role of dobutamine stress echocardiography in predicting outcome in 860 patients with known or suspected coronary artery disease.
78 : Value of pharmacologic stress echocardiography in risk stratification of patients with single-vessel disease: a report from the Echo-Persantine and Echo-Dobutamine International Cooperative Studies.
79 : Prognostic value of pharmacological stress echocardiography in patients with known or suspected coronary artery disease: a prospective, large-scale, multicenter, head-to-head comparison between dipyridamole and dobutamine test. Echo-Persantine International Cooperative (EPIC) and Echo-Dobutamine International Cooperative (EDIC) Study Groups.
80 : Prediction of mortality using dobutamine echocardiography.
81 : Long-term prognostic significance of dobutamine echocardiography in patients with suspected coronary artery disease: results of a 5-year follow-up study.
82 : Value of dobutamine stress echocardiography in determining the prognosis of patients with known or suspected coronary artery disease.
83 : Incremental prognostic value of stress echocardiography as an adjunct to exercise electrocardiography after uncomplicated myocardial infarction.
84 : Prognostic value of dobutamine stress echocardiography in predicting cardiac events in patients with known or suspected coronary artery disease.
85 : Long-term prognostic value of dobutamine stress echocardiography compared with myocardial perfusion scanning in patients unable to perform exercise tests.
86 : Assessment of cardiac risk before nonvascular surgery: dobutamine stress echocardiography in 530 patients.
87 : Dobutamine-atropine stress echocardiography for risk stratification in patients with chronic left ventricular dysfunction.
88 : Prognostic value of dobutamine stress echocardiography in patients with normal left ventricular systolic function.
89 : Prognostic significance of ST-segment elevation during dobutamine stress echocardiography.
