Cardiovascular stress response and coronary artery disease: evidence of an adverse postmenopausal effect in women

OBJECTIVES

To test the hypothesis that postmenopausal women demonstrate greater vascular instability, measured by enhanced cardiovascular stress responses during mental stress, compared with men and premenopausal women.

BACKGROUND

Recent data suggest that estrogen plays a role in regulating vascular tone. The possible consequences of estrogen deficiency during menopause on systemic vascular reactivity is largely unexplored.

METHODS

One hundred subjects (84 men and 16 women) underwent mental stress testing with radionuclide ventriculo graphy. Study subjects included 19 normal volunteers, 23 control subjects with chest pain syndromes or hypertension but without coronary artery disease, and 58 coronary artery disease subjects. The subjects performed a series of three mental stress tasks, during which hemodynamic data and radionuclide ventriculograms were obtained.

RESULTS

Overall, women demonstrated greater hemodynamic responses during mental stress measured by changes in heart rate, systolic and diastolic blood pressure, and double product compared with those of men (all p < 0.05). Women with coronary artery disease demonstrated greater heart rate, diastolic blood pressure, and double product stress responses than their male counterparts (all p < 0.05). Women of postmenopausal age demonstrated significantly greater systolic blood pressure reactivity than men or premenopausal women (p < 0.05).

CONCLUSIONS

Women of postmenopausal age have greater cardiovascular responses to stress than men or premenopausal women. These findings suggest an additional mechanism by which estrogen deficiency conveys a poor prognosis in female patients with coronary artery disease.

The differing prognostic utility of exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction

Previous studies have documented the prognostic utility of left ventricular ejection fraction response to exercise primarily in populations without prior myocardial infarction. We undertook a study to assess the prognostic utility of exercise left ventricular ejection fraction and segmental wall motion response during exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction.

METHODS

We examined the comparative prognostic utility of left ventricular ejection fraction and segmental wall motion response during upright bicycle exercise radionuclide ventriculography in 419 coronary artery disease patients with (n = 217) and without (n = 202) prior myocardial infarction using univariate and multivariate hierarchical regression analyses.

RESULTS

During an average followup period of 61 months, 96 patients (23%) suffered cardiac events, including 55/217 (25%) of the patients with prior myocardial infarction and 41/200 (21%) of the patients without prior myocardial infarction (p = ns). Both cumulative Kaplan-Meier survival analyses and stepwise hierarchical Cox survival analyses demonstrated that peak left ventricular ejection fraction < 55% was a significant predictor of cardiac events in patients without prior myocardial infarction (p = 0.04), whereas an exercise wall motion worsening score > or = 2 was a significant predictor in patients with a prior myocardial infarction (p = 0.0001).

CONCLUSIONS

The prognostic utility of exercise radionuclide ventriculography variables differ according to the presence or absence of prior myocardial infarction. Global function, assessed by peak left ventricular ejection fraction, adds the greatest prognostic information in patients without prior myocardial infarction, whereas regional function, assessed by exercise wall motion worsening, is the best predictor among patients with prior myocardial infarction.

Image enhancement of severely hypoperfused myocardia for computation of tomographic ejection fraction

Ejection fractions computed from 99mTc-sestamibi myocardial perfusion gated tomograms have demonstrated a high degree of accuracy and reproducibility. Although automated algorithms appear to provide reasonable endocardial outlines for patients over a broad spectrum of cardiac diseases, in cases of severe hypoperfusion, it is necessary to manually adjust contrast and brightness to judge whether borders are correct or must be altered.

METHODS

Midventricular horizontal and vertical long axis gated tomograms were generated for 116 studies chosen on the basis of extensive, severe myocardial perfusion defects. Automated software transformed cinematic tomograms into images demonstrating uniform appearance of the myocardium throughout the cardiac cycle. Transformed images were introduced to edge detection algorithms for subsequent calculation of ventricular volumes and ejection fractions.

RESULTS

Linear regression analysis demonstrated excellent intraobserver reproducibility for ejection fractions (r = 0.95) and volumes (r = 0.98). There was also good agreement of ejection fractions (r = 0.86) and volumes (r = 0.94) with values derived from an expert's manual drawings. In a subgroup of 22 patients, automated ejection fractions from transformed images demonstrated better agreement with independent first-pass values (r = 0.90) than did manual measurements derived from original data (r = 0.85).

CONCLUSION

Image enhancement algorithms succeeded in providing accurate, reproducible gated SPECT ejection fractions in the most difficult class of patients exhibiting severe hypoperfusion.

The secondary prevention of coronary artery disease

Randomized clinical trials demonstrate the efficacy of medical secondary prevention in coronary disease patients. The magnitude of risk reduction with exercise, diet, lipid modification, and smoking cessation is similar to other medical therapies for coronary disease such as aspirin, beta blockers, as well as coronary bypass surgery, (Table VI) In contrast to these therapies, however, secondary prevention stabilizes angiographic progression in about 50% of patients and induces regression in about 25% of patients. Both symptoms and perceived quality of life also are beneficially altered by secondary prevention programs, although possibly not by the magnitude reported for bypass surgery. These clinical trial results have led the American Heart Association, and the American College of Cardiology to strongly endorse secondary prevention. A reasonable projection based on these clinical trial data is that widespread use of these recommendations in the 12 million established coronary disease patients would significantly reduce coronary mortality and morbidity.

First-pass radionuclide angiocardiography with single-crystal gamma cameras

Both multicrystal and single-crystal detectors have been in use for more than 25 years for measurement of ejection fraction by analysis of images collected during the first-pass transit of radionuclides through the heart. Originally, multicrystal cameras were preferred, because they provided higher count rates than Anger cameras; however, over the years improvements in count rate capability and collimator design have enabled Anger cameras to perform equally well. This has become an important issue now that readily available 99mTc agents, such as sestamibi, enable evaluation of both myocardial function and perfusion from a single injection. The technical abilities of a particular camera determine which acquisition protocols are most likely to provide clinically useable images for the widest spectrum of patients. Electrocardiographic-gated list mode collection is highly desirable for first-pass imaging, providing the greatest flexibility of data review, rebinning, and analysis. Attention to quality control issues of data characterization and processing is important to ensure accuracy and precision of all measurements. Accurate determinations of ejection fraction of the left ventricle are possible routinely and, under favorable circumstances, of the right ventricle as well.

Automation of gated tomographic left ventricular ejection fraction

BACKGROUND

The feasibility of determining left ventricular (LV) ejection fraction (EF) from 99mTc-labeled sestamibi gated tomography (GSPECT) is well established. To improve precision of measurement, rules used by observers in processing tomograms were encoded for automation.

METHODS AND RESULTS

LV centers were estimated from activity centroids of time-difference images exceeding 50% of maximum counts. End diastole and end systole were defined by time-varying maximum count extremes. Endocardial borders were generated by fitting maximum locations with fifth-order two-dimensional harmonics, searching inward to predetermined thresholds, and reconciling endocardial with valve plane points. Regression analysis of GSPECT EF yielded r = 0.87 versus equilibrium gated blood pool in 75 patients and r = 0.87 versus gated first pass in 65 patients. GSPECT EF interobserver variability was r = 0.92 and intraobserver automatic versus manual linear correlation was r = 0.94. A subgroup of 25 studies was analyzed by six independent observers, for whom EF agreement with the core laboratory ranged from r = 0.93 to r = 0.96. Experienced observers judged it necessary to alter end-diastolic or end-systolic frames in 7% of patients, endocardial borders in 14%, and LV centers in 28%.

CONCLUSION

Results of automated GSPECT LV EF correlated well with those of manual GSPECT and gated first-pass and equilibrium blood pool values and were highly reproducible.

Heart rate variability reproducibility and stability using commercially available equipment in coronary artery disease with daily life myocardial ischemia

Heart rate variability (HRV) appears to be a strong predictor of death. The reproducibility of HRV measurements in patients with stable coronary artery disease (CAD) who have daily life myocardial ischemia, however, is unknown. Thirty patients with stable CAD (25 men and 5 women; aged 62 +/- 8 years) with daily life ischemia were studied with 2 consecutive 24-hour Holter monitoring recordings. Intra- and interobserver reproducibility of the HRV measures was high, with correlations ranging from 0.990 to 0.999 (p < 0.0001). Strong correlations between time and frequency domain HRV measures were observed (range 0.912 to 0.963; p < 0.0001). Both the frequency and duration of ischemia, measured by ST change, varied significantly by day for each patient (s = 155.5; p < 0.0001; s = 232.5, p < 0.0001, respectively). Correlations for HRV measurements between days remained high (range 0.871 to 0.983; p < 0.0001), despite stratification by magnitude of daily ischemia. Thus, 24-hour HRV measurements are stable in CAD patients with daily life myocardial ischemia over a short period, despite varying magnitudes of daily ischemia. These results support the use of HRV as a clinical tool and an outcome measure in future CAD intervention studies using commercially available equipment.

Gender-related differences in exercise ventricular function among healthy subjects and patients

Increasing numbers of women are undergoing noninvasive stress testing for coronary artery disease evaluation. Limited information is available regarding the presence, magnitude, and importance of gender-related differences in exercise ventriculography among the heterogeneous population of patients referred for noninvasive stress testing. Patients referred for exercise radionuclide ventriculography between 1979 and 1986 were evaluated, including 175 patients with a likelihood of coronary artery disease, 59 patients with angiographically normal coronary arteries, and 419 patients with coronary artery disease. Overall, women demonstrated higher resting left ventricular ejection fraction and lower delta left ventricular ejection fraction response to exercise compared with men. Although left ventricular response to exercise correlated with the underlying severity of coronary artery disease in both women and men, fewer women demonstrated a delta left ventricular ejection fraction >5 percent despite a lower prevalence of multivessel coronary artery disease compared with men. We conclude that gender-related differences in left ventricular response to exercise are present in a wide range of patients referred for testing.

Circadian variation of ambulatory myocardial ischemia. Triggering by daily activities and evidence for an endogenous circadian component

BACKGROUND

The morning peak in myocardial ischemia has been related to diurnal variations in physical and mental activities and to postural changes upon awakening. This study assesses (1) the effects of exogenous activity triggers at different times of the day and (2) the contribution of an endogenous (ie, activity- and posture-independent) circadian vulnerability for ambulatory ischemia.

METHODS AND RESULTS

Sixty-three stable coronary artery disease patients underwent ambulatory ECG monitoring and completed a structured diary assessing physical and mental activities. During 2519 hours of observation, a morning increase in ischemia coincided with increases in physical and mental activities, and an evening decrease in ischemia coincided with a decline in activities. During the morning, ischemic versus ischemia-free periods were more likely to occur with high levels of physical activity (P < .001). High physical activity triggered ischemia to a lesser but still significant extent (P < .05) in the afternoon but not in the evening (P = NS). High levels of mental activity triggered ischemia significantly during the morning (P < .04) and evening (P < .04) but not in the afternoon. When a residualized score procedure was used to correct ischemic time for each patient's simultaneously measured activities, for hourly heart rates, or for activity-related heart rate fluctuations, the circadian variation in ischemia was still observed (P < .001), with a peak at 6 AM. A significant increase in ischemia occurred immediately after awakening (P < .05), but activity-adjusted increases in morning ischemia persisted (P < .05) for 2 hours after awakening.

CONCLUSIONS

Exogenous factors (physical and mental activities) are most potent as triggers of ischemia during the morning hours, and the postural change after awakening contributes to the morning increase in ischemia. There is also evidence for an endogenous, activity-independent circadian influence on ischemic susceptibility that is independent of exogenous factors and that sustains the increase in ischemia upon awakening.

Triggers of myocardial ischemia during daily life in patients with coronary artery disease: physical and mental activities, anger and smoking

OBJECTIVES

This study assessed the potency of physical and mental activities and emotions (anger and anxiety) and smoking and other substance use as proximate triggers of ischemia in patients with coronary artery disease during daily life.

BACKGROUND

Myocardial ischemia occurs during a wide variety of activities in patients with coronary artery disease, but frequency and relative potency of physical and mental activities, smoking and use of caffeine and alcohol as triggers of ischemia during daily life have not been established.

METHODS

Patients (n = 63) with coronary artery disease and evidence of out-of-hospital ischemia kept a validated structured diary of physical and mental activities and psychologic states while undergoing ambulatory electrocardiographic monitoring for 24 to 48 h.

RESULTS

Ischemia occurred most frequently during moderately intense physical and mental activities. Patients spent the largest proportion of time engaged in low intensity physical and mental activities (p < 0.05), but the likelihood of ischemia was greatest during intense physical (p < 0.0001) and stressful mental activities (p < 0.03). The percentage of time in ischemia was elevated and approximately equivalent for high intensity physical and high intensity mental activities (5%) compared with 0.2% when patients were engaged in low intensity activities. Strenuous physical activity (e.g., effortful walking, p < 0.05) and the experience of intense anger were potent ischemic triggers, and heart rates at onset of ischemia increased with the intensity of physical and mental activity and with anger. Among smokers, ischemia was more than five times as likely when patients smoked than when they did not (during 24% vs. 5% of diary entries, p < 0.0001). Coffee and alcohol consumption were also related to ischemia (p < 0.05), but this association disappeared after controlling for concurrent cigarette smoking.

CONCLUSIONS

Triggers of ischemia in patients with coronary artery disease during daily life include not only strenuous exercise, but also activities involving low levels of exertion, such as anger and smoking. Mental activities appear to be as potent as physical activities in triggering daily life ischemia. Coffee and alcohol consumption are related to ischemia only by virtue of their associations with smoking.

The limited efficacy of exercise radionuclide ventriculography in assessing prognosis of women with coronary artery disease

Increasing numbers of women are undergoing stress testing for coronary artery disease evaluation. Limited study is available as to its efficacy in women. Four hundred nineteen patients with coronary artery disease (74 women and 345 men) referred for exercise radionuclide ventriculography between 1979 and 1986 were evaluated in a prospective cohort evaluation with 5-year follow-up. Exercise radionuclide ventriculographic variables were analyzed and compared between women and men. The prognostic efficacy of exercise radionuclide ventriculography was assessed separately for women and men among patients with coronary artery disease by Kaplan-Meier cumulative survival curves, univariate Cox regression analyses, and hierarchical stepwise Cox regression analyses. Overall, women demonstrated higher resting and peak left ventricular ejection fraction response to exercise than men. Ninety-six of 419 patients (23%) had cardiac events at 5-year follow-up. Although left ventricular response to exercise conveyed prognostic information in the combined and male populations (multivariate hierarchical analyses chi-square 11, p = 0.001 for delta left ventricular ejection fraction and chi-square 10, p = 0.002 for worsening exercise wall motion score), these variables were not found to be prognostically useful in women. Women with coronary artery disease demonstrated a worsened functional status, evidenced by greater compromise of exercise capacity, despite having less extensive anatomic disease than their male counterparts. We conclude that sex-related differences in left ventricular response to exercise limit the prognostic utility of exercise ventriculography in women with coronary artery disease.

Defensive hostility: relationship to multiple markers of cardiac ischemia in patients with coronary disease

Three studies assessed whether the combined traits of hostility and defensiveness identify a group of hostile individuals with functionally severe coronary artery disease (CAD). CAD patients completed the Cook-Medley Hostility Inventory (Ho) and the Marlowe-Crowne Social Desirability Scale (MC). Patients were classified into 4 groups: defensive hostile (DH: high Ho, high MC), low hostile (LH: low Ho, low MC), high hostile (HH: high Ho, low MC), and defensive (Def: low Ho, high MC). DH in comparison to HH, LH, and Def CAD patients demonstrate the greatest perfusion defects as measured by exercise thallium scintigraphy; DH patients exhibit the most frequent ischemic episodes during ambulatory electrocardiographic monitoring; and in a laboratory study, DH patients exhibit the most severe mental stress-induced ischemia assessed by echocardiography. Thus, the combination of high hostility and high defensiveness are associated with more functionally severe CAD and may predispose CAD patients to a more adverse prognosis.

Using gated technetium-99m-sestamibi SPECT to characterize fixed myocardial defects as infarct or artifact

Perfusion-scan fixed defects may result from soft tissue attenuation, decreasing test specificity for coronary disease and myocardial infarction (MI). Gated 99mTc-sestamibi SPECT may help differentiate MI from artifact since fixed defects with decreased function (wall motion and thickening) probably represent MI, whereas attenuation artifacts either have normal function or at least do not demonstrate markedly reduced function.

METHODS

Ungated resting and gated stress 99mTc-sestamibi SPECT was performed in 551 consecutive patients referred for evaluation of coronary disease. From resting and summed gated stress images, 180 patients (33%) were identified with isolated fixed defects. Function of the defects was assessed subjectively from gated stress images and results were correlated with clinical (history and/or ECG Q-waves) evidence of MI.

RESULTS

Of 102 patients with fixed defects and clinical MI, 98 (96%) had abnormal defect function. Of 78 patients with no clinical MI, 18 (23%) had decreased function of the defect, possibly indicating silent MI. In 60 of the 78 patients (77%) with no clinical MI, defect function was normal. Because most (91%) of fixed defects with normal systolic function occurred in women with anterior fixed defects (48%) or men with inferior fixed defects (43%), these were most likely attenuation artifacts. By reclassifying patients with fixed defects and normal function as normal, patients with unexplained fixed defects (no clinical MI) decreased from 14% to 3%.

CONCLUSION

Gating provides a valuable adjunct to 99mTc-sestamibi SPECT in characterizing fixed defects and potentially improving test specificity.

Defensive hostility: relationship to multiple markers of cardiac ischemia in patients with coronary disease

Three studies assessed whether the combined traits of hostility and defensiveness identify a group of hostile individuals with functionally severe coronary artery disease (CAD). CAD patients completed the Cook-Medley Hostility Inventory (Ho) and the Marlowe-Crowne Social Desirability Scale (MC). Patients were classified into 4 groups: defensive hostile (DH: high Ho, high MC), low hostile (LH: low Ho, low MC), high hostile (HH: high Ho, low MC), and defensive (Def: low Ho, high MC). DH in comparison to HH, LH, and Def CAD patients demonstrate the greatest perfusion defects as measured by exercise thallium scintigraphy; DH patients exhibit the most frequent ischemic episodes during ambulatory electrocardiographic monitoring; and in a laboratory study, DH patients exhibit the most severe mental stress-induced ischemia assessed by echocardiography. Thus, the combination of high hostility and high defensiveness are associated with more functionally severe CAD and may predispose CAD patients to a more adverse prognosis.

Induction of silent myocardial ischemia with mental stress testing: relation to the triggers of ischemia during daily life activities and to ischemic functional severity

OBJECTIVES

This study examined the relations among the triggers of ischemia during the activities of daily life, mental stress-induced ischemia in the laboratory and functional severity of ischemia on exercise testing.

BACKGROUND

Myocardial ischemia is readily induced with exercise testing, but most episodes of ischemia in daily life occur during relatively sedentary activities. Although mental and emotional arousal are known to trigger myocardial ischemia, mental stress testing induces ischemia in only approximately 50% of patients with active coronary disease. It is not known whether such patients are particularly susceptible to nonexertional ischemia during daily activity.

METHODS

We studied 45 men (mean age +/- SD 58 +/- 9 years) with coronary artery disease by means of 48-h Holter ambulatory electrocardiography for ST segment analysis and quantification of physical and mental activity with a structured diary system. These data were cross-tabulated with new left ventricular dyssynchrony (detected on two-dimensional echocardiography) induced by two mental stressors and by bicycle exercise.

RESULTS

During mental stress testing, 24 patients (53%) (Group I) had a new wall motion abnormality; the other 21 patients (Group II) did not. The average wall motion dyssynchrony score increased from 1.20 +/- 0.29 to 1.34 +/- 0.36 (p = 0.001), but the increase was less than that with exercise stress (1.52 +/- 0.41, p = 0.001). The total duration of ischemia during sedentary activities was greater in Group I (22.9 +/- 24.5 min) than in Group II (3.6 +/- 3.9 min, p = 0.025). Group I had more ischemic events while sedentary (23 of 290 diary entries) than did Group II (8 of 256 diary entries, p = 0.015). The magnitude of dyssynchrony with mental stress and the number of mental stressors capable of triggering ischemia were related to severity of ischemia with exercise.

CONCLUSIONS

Patients with ischemia during mental stress testing also have increased ischemia during sedentary activities in daily life. This finding may reflect greater functional severity of coronary artery disease or a propensity toward coronary vasoconstriction while sedentary.

Pathophysiologic factors governing the variability of ischemic responses to treadmill and bicycle exercise

Ischemic responses may vary considerably when patients with coronary artery disease (CAD) are tested serially, but the pathophysiologic mechanisms that govern this variability have not been well evaluated. We thus evaluated whether clinical, hemodynamic, physiologic, and anatomic factors influenced the variability in ischemic responses among 140 patients (mean age 54 +/- 11 years) subjected to both bicycle and treadmill exercise electrocardiography. Radionuclide ventriculography was obtained during bicycle exercise in each patient. The population included 77 patients with CAD, 21 patients with normal coronary arteriograms, and 42 patients with < 5% likelihood of CAD. Bicycle exercise evoked higher systolic blood pressure (p < 0.001) and double-product (p < 0.001) responses compared with treadmill exercise in the patients with CAD and in the normal subjects, and it evoked a lower frequency of chest pain (12% vs 41%, p < 0.001) in the 34 patients with CAD who had ST-segment depression during both exercise tests. There was a high frequency of variability in ischemic responses during treadmill versus bicycle exercise: 22 (39%) of the 56 CAD patients who had exercise-induced ST-segment depression manifested this response during one stress test only. This variability was strongly related to the functional and anatomic magnitude of disease. Ischemic variability decreased progressively as the response of left ventricular ejection fraction (LVEF) to exercise worsened progressively (p = 0.003 by analysis of variance), from 83% in those with an LVEF increase of > 10% with exercise to only 13% in those with an LVEF fall of > or = 5% with exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Triggers of angina and ST-segment depression in ambulatory patients with coronary artery disease: evidence for an uncoupling of angina and ischemia

This study evaluated daily-life physical and mental triggers of painful and painless myocardial ischemia and of anginal pain in patients with coronary artery disease (CAD) by using ambulatory electrocardiographic monitoring and a structured diary. Eighty-five percent of ambulant ischemic episodes occurred without chest pain; 66% of anginal pain reports were made in the absence of ischemic ST-segment depression. Chest pain reports in the absence of ischemia could not be attributed to "borderline" ST-segment changes. Compared with silent ischemia, painful ischemia was triggered at higher levels of physical activity (p < 0.05) and at higher levels of self-rated effort and negative emotion (p < 0.05). Painful episodes were associated with greater-magnitude ST depression (p < 0.02), but a substantial percentage of episodes with > or = 2 mm and > or = 3 mm ST depression were silent. These results reveal an uncoupling of anginal symptoms from ambulatory ischemic episodes in patients with CAD during daily life. In addition, specific activities and emotions correlate with the presence or absence of anginal symptoms as much as does the presence of ischemic ST depression. These results may have implications for antiischemic and antianginal treatment strategies.

Is 'silent' myocardial ischemia really as severe as symptomatic ischemia? The analytical effect of patient selection biases

BACKGROUND

The clinical significance of exercise-induced chest pain remains controversial, as reflected by sharply discordant clinical results within the medical literature. Thus, we developed a prospective study to compare the functional significance of silent versus symptomatic ischemia and to evaluate whether patient selection biases influence this analysis.

METHODS AND RESULTS

We evaluated 117 patients (mean age, 63 +/- 9 years) with ischemic ST-segment depression during treadmill testing. Each patient underwent Tl-201 myocardial perfusion single-photon emission computed tomography (SPECT) after exercise followed by 24-ambulatory ECG monitoring. Patients were divided into silent versus symptomatic cohorts and were compared for the degree of hemodynamic, exercise and ambulatory ECG, and thallium abnormalities during stress testing. Analyses were repeated as the patient population became increasingly restricted. Compared with the silent patients, patients with chest pain during exercise had a shorter exercise duration (P < .009), lower peak heart rate (P = .009) and double product (P = .005), lower heart rate threshold for ST depression (P < .05), more episodes of ambulatory ST-segment depression (P < .05), a higher frequency of ischemia abnormalities during Tl-201 SPECT (P = .02), and higher summed Tl reversibility scores (P = .002). As the population became increasingly restricted, the relative magnitude of differences in silent versus symptomatic cohorts diminished, whereas the absolute magnitude of ischemic abnormalities progressively increased in both cohorts. For example, within the restricted group having ischemia on both exercise and ambulatory ECG, 50% of the silent cohort had severe ischemia on Tl SPECT (five or more reversible defects) and more than one third demonstrated the ominous finding of transient left ventricular dilation after exercise.

CONCLUSIONS

The induction of chest pain is associated with substantially more functional abnormalities when it is analyzed in a relatively "broad-spectrum" coronary artery disease population; by contrast, chest pain tends to lose its apparent value as a clinical test parameter when its analysis is restricted to coronary artery disease populations with a greater a priori likelihood of manifesting inducible ischemia. These findings may help resolve some of the previous discordant literature reports.

Effect of motion on thallium-201 SPECT studies: a simulation and clinical study

Although patient motion on 201Tl SPECT studies has been reported as a source of artifacts, systematic studies on motion patterns and resultant artifacts are lacking. Accordingly, we simulated 74 motion patterns upon a normal study. The tomograms were assessed for presence of defects: The "motion pixel area index" ranged from 1 to 83; 26 of 30 (87%) simulations with an index > or = 21 had defects, whereas 38 of 44 (86%) simulations with an index < 21 were normal. Defect location was dependent on motion direction; defect intensity was dependent on its magnitude and timing. Review of data acquisition in 164 recent normal patient studies revealed motion in 42 (26%). Motion was generally minimal and caused defects in only seven (4%). Thus, mild motion is unlikely to produce defects. In our laboratory, motion is now an infrequent source of artifacts; severe motion produces recognizable patterns that depend on its direction, magnitude and timing.

Prevalence and functional significance of transient ST-segment depression during daily life activity: comparisons of ambulatory ECG with stress redistribution thallium 201 single-photon emission computed tomographic imaging

To assess the prevalence and functional significance of ischemic ambulatory ECG responses, we prospectively performed ambulatory ECG monitoring in 244 patients (mean age 61 +/- 10 years) referred for stress redistribution thallium 201 myocardial perfusion scintigraphy. The prevalence of ST-segment depression during ambulatory ECG was 33% among patients with a positive exercise ECG, but prevalence varied in selected patient subgroups. Among three groups with coronary artery disease (CAD), the group with ambulatory ECG ischemia (group 1) had a greater frequency of ischemic thallium responses (p = 0.07), a greater median number of reversible thallium defects (p < 0.05), and a greater summed thallium "reversibility" score (p < 0.05) than did the group with a positive exercise ECG but negative ambulatory ECG response (group 2) or that with negative exercise and ambulatory ECG responses (group 3). Exercise ST depression in group 1 versus group 2 was significantly greater (p = 0.002), occurred at a lower heart rate threshold (p = 0.002), and lasted longer after exercise (p = 0.001). Notably, one third of group 1 patients also manifested evidence of transient ischemic dilation of the left ventricle after exercise (p < 0.01 vs groups 2 and 3), a sign of severe ischemia. However, although functionally less "sick" than group 1 patients, 66% of group 2 patients and 50% of group 3 patients still had an ischemic thallium response, which was sometimes severe. Thus transient ischemia during ambulatory ECG monitoring identifies a functionally sicker cohort of patients with CAD and occurs in approximately one third of CAD patients with positive results of exercise tests. A negative ambulatory ECG response, however, does not exclude functionally significant disease among CAD patients. These results imply that caution should be applied in the interpretation of a negative ambulatory ECG response for the purpose of patient risk stratification.

Hostility and myocardial ischemia in coronary artery disease patients: evaluation by gender and ischemic index

Two studies assess relationships of hostility to extent and severity of exercise-induced cardiac ischemia and daily life ischemia in patients with coronary artery disease (CAD). CAD patients (N = 80) who underwent exercise tomographic thallium testing to assess myocardial perfusion completed the Cook-Medley Hostility Inventory (Ho). A Composite Hostility (Chost) score obtained from the Ho scale was also used. Statistically controlling for the effects of gender in the full sample (N = 80), Chost was positively correlated with severity of perfusion defects (r = 0.22, p < 0.05). This relationship was nonsignificant in the 63 male patients, but was significant among women (N = 17, r = 0.42, p < 0.05) and among middle-aged men (less than 60 years, N = 17, r = 0.55, p < 0.05). In an overlapping sample of 42 CAD patients with ischemia (ST-segment depression > or = 1 mm) during 24 to 48 hours of ambulatory electrocardiographic monitoring, after controlling for gender, both Ho and Chost were positively correlated with total minutes of ischemia (r = 0.28 and r = 0.29, respectively, p < 0.05). In addition, there was a significant gender x hostility interaction, with stronger relationships with hostility evident for women. Results from these two studies indicate that in patients with coronary artery disease, hostility traits are significantly correlated with extent of daily life ischemia and with severity of exercise-induced myocardial ischemia. These relationships appear to be significant among female and middle aged male patients, but may be less evident among older male patients.