Blunted nighttime blood pressure dipping in postmenopausal women.

Blunting of the normal drop in blood pressure (BP) from day to night is emerging as a strong prognostic indicator of cardiovascular morbidity and mortality. This study evaluated the effects of natural menopause on BP dipping in African American and white women. A total of 112 women (62 premenopausal and 50 postmenopausal) took part in the study. Pre- and postmenopausal groups were comparable in terms of clinic BP, body mass index, and ethnic composition. Ambulatory BP was recorded over 24 h during a typical workday, with measurements programmed to be taken every 15 min during waking hours and every 30-minutes during sleeping hours. Nocturnal BP dipping was defined as the difference between waking and sleep BP. Waking BP did not differ by menopausal status. However, nocturnal systolic BP (SBP) and diastolic BP (DBP) dipping were attenuated in postmenopausal women, with both SBP (P < .05) and DBP (P < .05) higher during nighttime sleep in postmenopausal than in premenopausal women. Ethnicity was also related to BP dipping, with African American women tending to show blunted SBP dipping (P = .055) compared with white women; BP dipping was most blunted in postmenopausal African American women. These observations suggest that blunted nighttime BP dipping may contribute to increased cardiovascular disease risk in postmenopausal women.

Simulation technology for health care professional skills training and assessment.

Changes in medical practice that limit instruction time and patient availability, the expanding options for diagnosis and management, and advances in technology are contributing to greater use of simulation technology in medical education. Four areas of high-technology simulations currently being used are laparoscopic techniques, which provide surgeons with an opportunity to enhance their motor skills without risk to patients; a cardiovascular disease simulator, which can be used to simulate cardiac conditions; multimedia computer systems, which includes patient-centered, case-based programs that constitute a generalist curriculum in cardiology; and anesthesia simulators, which have controlled responses that vary according to numerous possible scenarios. Some benefits of simulation technology include improvements in certain surgical technical skills, in cardiovascular examination skills, and in acquisition and retention of knowledge compared with traditional lectures. These systems help to address the problem of poor skills training and proficiency and may provide a method for physicians to become self-directed lifelong learners.

Implementation of a four-year multimedia computer curriculum in cardiology at six medical schools.

The pressures of a changing health care system are making inroads on the commitment and effort that both basic science and clinical faculty can give to medical education. A tool that has the potential to compensate for decreased faculty time and thereby to improve medical education is multimedia computer instruction that is applicable at all levels of medical education, developed according to instructional design principles, and supported by evidence of effectiveness. The authors describe the experiences of six medical schools in implementing a comprehensive computer-based four-year curriculum in bedside cardiology developed by a consortium of university cardiologists and educational professionals. The curriculum consisted of ten interactive, patient-centered, case-based modules focused on the history, physical examination, laboratory data, diagnosis, and treatment. While an optimal implementation plan was recommended, each institution determined its own strategy. Major goals of the project, which took place from July 1996 to June 1997, were to identify and solve problems of implementation and to assess learners' and instructors' acceptance of the system and their views of its value. A total of 1,586 students used individual modules of the curriculum 6,131 times. Over 80% of students rated all aspects of the system highly, especially its clarity and educational value compared with traditional lectures. The authors discuss the aspects of the curriculum that worked, problems that occurred (such as difficulties in scheduling use of the modules in the third year), barriers to change and ways to overcome them (such as the type of team needed to win acceptance for and oversee implementation of this type of curriculum), and the need in succeeding years to formally assess the educational effectiveness of this and similar kinds of computer-based curricula.

Electrocardiographic differentiation of the ST-segment depression of acute myocardial injury due to the left circumflex artery occlusion from that of myocardial ischemia of nonocclusive etiologies.

Lead distributions of peak ST-segment depression were compared between patients undergoing left circumflex artery percutaneous transluminal coronary angioplasty and exercise tolerance test. Localization of peak ST-segment depression to leads V2 or V3 was 96% specific and 70% sensitive for differentiating ischemia due to occlusion of left circumflex artery occlusion from nonocclusive ischemia.

Effects of mental stress on myocardial ischemia during daily life.

OBJECTIVE: To determine the relative risk of myocardial ischemia triggered by specific emotions during daily life. DESIGN AND SETTING: Relative risk was calculated by the recently developed case-crossover method, in which the frequency of a presumed trigger during nonischemic, or control, hours is compared with the trigger's frequency during ischemic, or case, hours. Outpatients at Duke University Medical Center, Durham, NC, underwent 48 hours of ambulatory electrocardiographic (ECG) monitoring with concurrent self-report measures of activities and emotions. Occurrences of negative emotions in the hour before the onset of myocardial ischemia were compared with their usual frequency based on all hours in which ischemia did not occur. SUBJECTS: From a sample of 132 patients with coronary artery disease and recent evidence of exercise-induced ischemia who underwent 48 hours of ambulatory ECG monitoring, 58 patients exhibited ambulatory ischemia and were included in the analysis. OUTCOME MEASURES: Myocardial ischemia during 48-hour ECG monitoring was defined as horizontal or downsloping ST-segment depression of 1 mm (0.1 mV) or more for 1 minute or longer compared with resting baseline. The ECG data were cross-tabulated with subjects' concurrent diary ratings of 3 negative emotions-tension, sadness, and frustration-and 2 positive emotions-happiness and feeling in contro-on a 5-point scale of intensity. RESULTS: The unadjusted relative risk of occurrence of myocardial ischemia in the hour following high levels of negative emotions was 3.0 (95% confidence interval [CI], 1.5-5.9; P<.01) for tension, 2.9 (95% CI, 1.0-8.0; P<.05) for sadness, and 2.6 (95% CI, 1.3-5.1; P<.01) for frustration. The corresponding risk ratios adjusted for physical activity and time of day were 2.2 (95% CI, 1.1 -4.5; P<.05) for tension, 2.2 (95% CI, 0.7-6.4; P=.16) for sadness, and 2.2 (95% CI, 1.1-4.3; P<.05) for frustration. CONCLUSIONS: Mental stress during daily life, including reported feelings of tension, frustration, and sadness, can more than double the risk of myocardial ischemia in the subsequent hour. The clinical significance of mental stress-induced ischemia during daily life needs to be further evaluated.

Mental stress--induced myocardial ischemia and cardiac events.

OBJECTIVE: To assess the clinical significance of mental stress-induced myocardial ischemia in patients with coronary artery disease (CAD). DESIGN AND SETTING: Cohort study in outpatients in a tertiary care teaching hospital assessed at baseline and followed up for up to 5 years. SUBJECTS: A total of 126 volunteer patients (112 men, 14 women; mean age, 59 years) with documented CAD and exercise-induced myocardial ischemia. OUTCOME MEASURES: Patients underwent baseline mental stress and exercise testing using radionuclide ventriculography and 48-hour Holter monitoring. Patients were subsequently contacted by mailed questionnaires or telephone to document cardiac events, including death, nonfatal myocardial infarction, and cardiac revascularization procedures. Logistic regression and Cox proportional hazards models were used to examine the prognostic value of the ischemic measures after adjusting for such potential confounding factors as age, baseline left ventricular ejection fraction (LVEF), and history of myocardial infarction. RESULTS: Twenty-eight patients (22%) experienced at least 1 cardiac event. Baseline mental stress-induced ischemia was associated with significantly higher rates of subsequent cardiac events (odds ratio, 2.8; 95% confidence interval [CI], 1.0-7.7; P < .05). The LVEF change during mental stress was significantly related to event-free survival (risk ratio [RR], 2.4; 95% CI, 1.12-5.14; P = .02), controlling for age, history of prior myocardial infarction, and baseline LVEF. This relationship remained significant after controlling for electrocardiogram (ECG)-defined ischemia during exercise (RR, 2.2; 95% CI, 1.01-4.81; P < .05). The RR for ECG-defined ischemia during exercise testing was 1.9 (95% CI, 0.95-3.96; P = .07) and the RR for ambulatory ECG ischemia was 0.75 (95% CI, 0.35-1.64; P = .47). CONCLUSIONS: The presence of mental stress-induced ischemia is associated with significantly higher rates of subsequent fatal and nonfatal cardiac events, independent of age, baseline LVEF, and previous myocardial infarction, and predicted events over and above exercise-induced ischemia. These data suggest that the relationship between psychological stress and adverse cardiac events may be mediated by the occurrence of myocardial ischemia.

Association of physical fitness and transient myocardial ischemia in patients with coronary artery disease.

PURPOSE: To examine the relationship between physical fitness and transient myocardial ischemia (TMI) in the laboratory and during daily life, in a sample of coronary patients with a recent positive exercise test. METHODS: 47 patients with coronary disease (CAD) participated in laboratory mental and exercise stress testing and 48-hour outpatient Holter monitoring after being withdrawn from ant-ischemic medications. During laboratory testing, left ventricular performance was assessed by radionuclide ventriculography. Physical fitness was assessed by measurement of oxygen consumption during symptom-limited exercise treadmill testing. RESULTS: Higher physical fitness subjects were less likely to exhibit wall-motion abnormalities in response to mental stress (P < .05), and to exercise stress (P < .05) testing. They also had smaller decreases in left ventricular ejection fraction (LVEF) in response to mental stress than less fit subjects (P .056), and exhibited a mean increase in LVEF during exercise, compared to the less fit subjects who exhibited a decrease in LVEF (P < .02). Moreover, higher fit subjects exhibited fewer episodes of TMI (P < .04), for a shorter duration (P < .04), and less total ischemic burden (P < .04) during Holter monitoring. CONCLUSION: These findings suggest that within a population of CAD patients, higher levels of physical fitness are associated with less TMI assessed in the laboratory and during routine activities of daily living.

Mental stress-induced ischemia in the laboratory and ambulatory ischemia during daily life. Association and hemodynamic features.

BACKGROUND: The purpose of this study was to determine the correspondence of mental stress-induced ischemia in the laboratory with ambulatory ischemia and to assess the relationship between hemodynamic responses to mental stress and the occurrence of ischemia. Although exercise testing is usually used to elicit myocardial ischemia, ischemia during daily life usually occurs at relatively low heart rates and in the absence of strenuous physical exercise. Mental stress has been shown to trigger ischemic events in the laboratory at lower heart rates but at blood pressures comparable to exercise. We therefore compared the extent to which mental stress and exercise testing identify patients who develop ischemia out of hospital. METHODS AND RESULTS: One hundred thirty-two patients with documented coronary disease and recent evidence of exercise-induced myocardial ischemia underwent 48-hour ambulatory monitoring and radionuclide ventriculography during exercise and mental stress testing. Patients who displayed mental stress-induced ischemia in the laboratory were more likely to exhibit ischemia during daily life (P < .021). Furthermore, patients who exhibited ischemia during ambulatory monitoring displayed larger diastolic blood pressure (P < .006), heart rate (P < .039), and rate-pressure product responses (P < .018) during mental stress. CONCLUSIONS: Among patients with prior positive exercise stress tests, mental stress-induced ischemia, defined by new wall motion abnormalities, predicts daily ischemia independent of exercise-induced ischemia. Exaggerated hemodynamic responses during mental stress testing also identify individuals who are more likely to exhibit myocardial ischemia during daily life and mental stress.

Relative importance of electrode placement over number of channels in transient myocardial ischemia detection by Holter monitoring.

To compare the efficacy of 3-channel ambulatory electrocardiographic monitoring (Holter monitoring) with 2-channel Holter monitoring in the detection of transient myocardial ischemia (TMI), channels CM2, CM5, and modified II were studied. Sixty patients with documented coronary artery disease underwent 48-hour Holter monitoring during their normal daily life, followed by exercise stress testing in the laboratory monitored by means of radionuclide ventriculography and standard 12-lead electrocardiography. Analysis revealed that 3-channel Holter monitoring identified 24 patients with a total of 205 TMI episodes and a total ischemic burden of 371.00 mV-min. By itself, CM2 would have detected only 3 patients (13% of the TMI population), 6 TMI episodes (3% of the total TMI episodes), and a 2.4 mV-min ischemic burden (0.7% of the total ischemic burden). Modified II alone would have identified 17 patients (71% of the TMI population), 160 TMI episodes (78% of the total TMI episodes), and 307.24 mV-min of the ischemic burden (82% of the total ischemic burden). The combination of CM5/modified II identified 23 patients (96% of the TMI population), 201 TMI episodes (98% of the total TMI episodes), and 370.44 mV-min of the ischemic burden (98% of the total ischemic burden). These findings suggest that the electrode placement is more important than the absolute number of channels in the detection of TMI by Holter monitoring.

Accuracy and reliability of apical S3 gallop detection.

This study assessed physician performance in detecting the apical S3 gallop using a cardiology patient simulator. Six physicians (two cardiology fellows, two medicine residents, and two attending physicians) performed two sets of 24 cardiac examinations that included the presence or absence of an apical S3 gallop. All the examiners were able to significantly alter the prior odds of an apical S3 gallop's being present, but the cardiology fellows had higher sensitivities. Sensitivity was lower for detecting soft S3 gallops, and specificity was lower when a diastolic murmur was also present. Physician performance in detecting apical S3 gallops is variable, but can be excellent.

Does hypotension during dobutamine stress echocardiography correlate with anatomic or functional cardiac impairment?

The development of hypotension during various exercise stress tests has been correlated with the presence of multivessel coronary artery disease and impaired left ventricular contractility. Hypotension may also occur during dobutamine stress echocardiography; however, its anatomic and functional significance remains unknown. As part of an ongoing study of restenosis, dobutamine stress echocardiography and diagnostic cardiac catheterization were performed on the same day in 105 outpatients approximately 6 months after percutaneous coronary revascularization (balloon angioplasty or directional coronary atherectomy) to determine the anatomic and functional significance of dobutamine-induced hypotension. Dobutamine was infused in stepwise increments to a maximum rate of 30 micrograms/kg/min. Hypotension was defined as a reduction in systolic blood pressure of > or = 15 mm Hg. Anatomic abnormalities were defined by quantitative coronary angiography and functional abnormalities by digitized two-dimensional stress echocardiography. Clinical, angiographic, hemodynamic, and electrocardiographic data underwent multivariable regression analysis to determine their ability to predict independently the development of dobutamine-induced hypotension. Dobutamine-induced hypotension was not associated with the presence of severity of coronary artery disease or with echocardiographic wall motion abnormalities. Univariable predictors of stress-induced hypotension included high baseline systolic blood pressure, advanced age, and high left ventricular ejection fraction. Only a high baseline systolic blood pressure contributed independent predictive information in multivariable stepwise logistic regression analysis. Therefore, the development of hypotension during dobutamine stress echocardiography, unlike that during traditional exercise stress tests, is not associated with the presence of significant coronary artery disease or left ventricular dysfunction.

Multimedia computer-assisted instruction in cardiology.

BACKGROUND: Medical education faces problems caused by increasing restraints on resources. A multicenter consortium combined simulation and multimedia computer-assisted instruction (MCAI) to develop unique interactive teaching programs that can address a number of these problems. We describe the consortium, the MCAI system, the programs, and a multicenter evaluation of technical and educational performance. METHODS: The MCAI system uses computer-controlled access to full-screen, full-motion, and full-color laser disc video in combination with digitized sound, images, and graphics stored on removable media. The Socratic teaching method enhances interaction and guides learners through the patient's history, cardiovascular physical examination, laboratory evaluation, and therapy. Self-instruction and instructor-led modes of function are possible. The first five programs, based on simulations of specific cardiology problems, were distributed to four medical centers. Questionnaires evaluated technical function and medical student opinions, while behaviors and scores were automatically tracked and tabulated by program administration software. RESULTS: The MCAI system functioned reliably and accurately in all modes and at all sites. The programs were highly rated. Student ratings, scores, and behaviors were independent of institution and mode of use. CONCLUSION: A multicenter educational consortium developed a system to produce unique, sophisticated MCAI programs in cardiology. Both system and programs functioned reliably at four institutions and were highly rated by fourth-year medical students. With this enthusiastic reception, the economies and strengths associated with MCAI make it an attractive solution to a number of problem areas, and it will likely play an increasingly important role.

Usefulness of dobutamine echocardiography for detecting restenosis after percutaneous transluminal coronary angioplasty.

To determine the usefulness of dobutamine stress echocardiography for detecting restenosis after percutaneous transluminal coronary angioplasty, the results of coronary arteriography and dobutamine stress echocardiography were compared in 103 patients 6 months after percutaneous transluminal coronary angiography. The dobutamine stress echocardiograms were obtained on the same day as the coronary arteriograms, which were analyzed by both quantitative and visual estimates of luminal narrowing. The angiographic restenosis rate was 44% by quantitative and 31% by visual estimates of stenosis. Dobutamine stress echocardiography was abnormal in 38% of previously dilated regions with restenosis and normal in 79% of previously dilated regions without restenosis by quantitative coronary angiography. Dobutamine stress echocardiography was concordant in 69% of 16 patients with multivessel disease compared with 40% of 41 patients with 1-vessel disease (p < 0.05). By quantitative coronary angiography, 64% of patients with significant disease in the left anterior descending artery were identified by dobutamine stress echocardiography compared to 12 and 24% of patients with disease in the left circumflex and right coronary arteries, respectively (p < 0.009). Concordance was seen in 79% of patients with baseline wall motion abnormalities compared with 54% of patients without baseline wall motion abnormalities. Dobutamine stress echocardiography has a low sensitivity but high specificity for detecting restenosis after coronary angioplasty, which may be explained in part by the high prevalence of 1-vessel disease in this patient population. The variables associated with significantly higher degrees of concordance were the presence of left anterior descending artery disease, multivessel disease, and baseline wall motion abnormalities.

Teaching cardiovascular examination skills: results from a randomized controlled trial.

PURPOSE: To evaluate the effectiveness of a teaching program designed to improve interns' cardiovascular examination skills. PARTICIPANTS: All 56 interns rotating on a mandatory 4-week inpatient cardiology service during 1 academic year (July 1989-June 1990). METHODS: We randomly assigned interns to receive either an eight-session physical diagnosis course ("teaching group") taught on the cardiology-patient simulator ("Harvey") or to receive no supplemental teaching ("control group"). Before and immediately after the teaching or control period, the interns were evaluated on three preprogrammed simulations (mitral regurgitation, MR; mitral stenosis, MS; aortic regurgitation, AR). Immediately after the control or the intervention period, the interns also evaluated patient volunteers. RESULTS: There were no baseline differences in the interns' ability to correctly identify the disease simulations. Both the intervention and the control interns showed similar, moderate improvement in their diagnostic ability on the simulator. The intervention interns improved on MR from 42% correct to 54% correct; on MS from 8% correct to 23% correct; and on AR from 46% correct to 58% correct. The intervention and the control interns performed similarly on patient volunteers: for MR, 20% correct versus 31%; for AR, 29% correct versus 33%; and for aortic sclerosis, 64% correct versus 33%, respectively. CONCLUSIONS: The interns had difficulty correctly identifying three valvular heart disease simulations before and after an educational intervention employing a cardiovascular-patient simulator. At no time did the proportion of correct responses exceed 64%. Our teaching intervention during internship was either of insufficient intensity or of insufficient duration to produce significant improvement in cardiovascular diagnostic skills.

Relation of cardiovascular responses to mental stress and cardiac vagal activity in coronary artery disease.

Forty-six patients with documented coronary artery disease were studied to examine the relation of cardiovascular reactivity to mental stress and cardiac vagal activity. Cardiac vagal activity was measured by means of frequency-domain analysis of heart rate variability with 48-hour out-of-hospital Holter monitoring. The amplitude of the high-frequency component (0.16 to 0.40 Hz) of heart rate variability is considered to be an index of cardiac vagal activity. Cardiovascular reactivity was measured in the laboratory during a 3-minute public speaking task. Results revealed that (1) the amplitude of the high-frequency component was significantly higher during sleep (24.6 +/- 11.3 ms) than during waking (18.2 +/- 8.0 ms) (p = 0.002); (2) compared to subjects with low diastolic blood pressure reactivity, those who displayed high diastolic blood pressure reactivity exhibited a significantly lower amplitude of the high-frequency component (19.2 +/- 6.9 vs 23.4 +/- 9.6 ms, p = 0.03). These results indicate that decreased cardiac vagal activity may contribute to the exaggerated diastolic blood pressure reactivity to mental stress in patients with coronary artery disease.

Assessing housestaff diagnostic skills using a cardiology patient simulator.

OBJECTIVE: To assess the cardiovascular physical examination skills of internal medicine housestaff. DESIGN: Cross-sectional assessment of housestaff performance on three valvular abnormality simulations conducted on the cardiology patient simulator, "Harvey." Evaluations were done at the beginning (session I) and end (session II) of the academic year. SETTING: Duke University Medical Center internal medicine training program. SUBJECTS: Sixty-three (59%) of 107 eligible internal medicine housestaff (postgraduate years 1 through 3) agreed to participate and completed session I; 60 (95%) completed session II. MEASUREMENTS: All volunteers were tested on three preprogrammed simulations (mitral regurgitation, mitral stenosis, and aortic regurgitation). RESULTS: The overall correct response rates for all housestaff were 52% for mitral regurgitation, 37% for mitral stenosis, and 54% for aortic regurgitation. No difference was noted in correct response rates between sessions I and II. For mitral regurgitation, correct assessment of the contour of the holosystolic murmur predicted a correct diagnosis (P = 0.002). For mitral stenosis, identification of an opening snap and proper characterization of the mitral area diastolic murmur predicted a correct diagnosis (P < 0.0001). No individual observations were noted for the aortic regurgitation simulation, whose identification by the housestaff was associated with a correct diagnosis. CONCLUSIONS: Housestaff had difficulty establishing a correct diagnosis for simulations of three common valvular heart diseases. Accurate recognition of a few "key" observations was associated with a correct diagnosis in two of the three diseases. Teaching housestaff to elicit and interpret a few critical signs accurately may improve their physical diagnosis abilities.