Search

Background . We evaluated the value of coronary artery calcification (CAC) score in coronary artery disease (CAD) detection in asymptomatic hemodialysis (HD) patients by evaluating the association among CAC score, exercise electrocardiography (EECG), and Thallium-201 dipyridamole scintigraphy. Correlation between aortic pulse wave velocity (PWV) and CAC score was also evaluated. Methods . CAC score was assessed with conventional computed tomography in 40 patients. Thirty patients completed EECG and 25; those with a positive CAC score and/or a positive EECG performed Thallium dipyridamole scintigraphy. Carotid-femoral PWV was assessed in all patients. Results . There was no association among CAC score and EECG or Thallium dipyridamole scintigraphy. In contrast, CAC score was correlated with aortic PWV. Conclusion . The previous results question the role of CAC score in the detection of CAD in asymptomatic HD patients. The correlation between CAC score and aortic PWV raises the possibility that CAC score represents more an indicator of coronary artery medial wall calcification than a marker of CAD. [ABSTRACT FROM AUTHOR]

Objective: It is known that exercise-induced ischemia in patients with coronary artery disease (CAD) may produce QRS prolongation in the surface electrocardiogram (ECG). To investigate the presence of exercise-induced Q-wave prolongation in patients with single-vessel CAD and Q-wave myocardial infarction (MI), in association with the presence of reversible perfusion defects during thallium scintigraphy in the infarcted area. Methods: 107 consecutive patients (89 males, mean age 56±8 years) were evaluated. All patients underwent coronary arteriography, maximal treadmill exercise testing and thallium-201 scintigraphy. Q-wave duration was measured both before exercise testing and during maximal heart rate from 12-lead ECGs recorded with a paper speed of 50 mm/s. Results: Only 57 out of the 107 studied patients showed reversible perfusion defects in the infarcted area during thallium scintigraphy. Q-wave duration was significantly increased from the resting to the stress ECG (ΔQ-wave duration) in patients with reversible perfusion defects in the infarcted areas (10±13 ms), but not in patients with fixed defects in the infarcted zone (−2.0±5 ms, p<0.01). The sensitivities and the specificities of Q-wave prolongation, ST segment elevation, and the combination of ST segment elevation with ST segment depression in the reciprocal leads for the detection of myocardial viability in the infarcted area were 82%, 48%, 29% and 88%, 50%, and 90%, respectively. Conclusions: Exercise-induced Q-wave prolongation is demonstrated in those patients with single-vessel CAD and a recent MI who show reversible perfusion defects in thallium scintigraphy. Exercise-induced Q-wave prolongation was found to be a sensitive and specific ECG marker for the detection of myocardial viability in the infarcted area. [Copyright &y& Elsevier]

Background Exercise testing after acute myocardial infarction has limited prognostic accuracy. We prospectively used stress-recovery, heart rate-adjusted, ST-segment analysis to predict cardiac death in this clinical setting. [ABSTRACT FROM PUBLISHER]

Background Patients with known or suspected coronary disease are often investigated to facilitate risk assessment. We sought to examine the cost-effectiveness of strategies based on exercise echocardiography and exercise electrocardiography.Methods and results We studied 7656 patients undergoing exercise testing; of whom half underwent exercise echocardiography. Risk was defined with the Duke treadmill score for those undergoing exercise electrocardiography alone, and by the extent of ischaemia by exercise echocardiography. Cox proportional hazards models, risk adjusted for pretest likelihood of coronary artery disease, were used to estimate time to cardiac death or myocardial infarction. Costs (including diagnostic and revascularisation procedures, hospitalisations, and events) were calculated, inflation-corrected to year 2000 using Medicare trust fund rates and discounted at a rate of 5%. A decision model was employed to assess the marginal cost effectiveness (cost/life year saved) of exercise echo compared with exercise electrocardiography. Exercise echocardiography identified more patients as low-risk (51% vs 24%, p<0.001), and fewer as intermediate- (27% vs 51%, p<0.001) and high-risk (22% vs 4%); survival was greater in low- and intermediate-risk and less in high-risk patients. Although initial procedural costs and revascularisation costs (in intermediate-high risk patients) were greater, exercise echocardiography was associated with a greater incremental life expectancy (0.2 years) and a lower use of additional diagnostic procedures when compared with exercise electrocardiography (especially in lower risk patients). Using decision analysis, exercise echocardiography (∈2615/life year saved) was more cost effective than exercise electrocardiography.Conclusion Exercise echocardiography may enhance cost-effectiveness for the detection and management of at risk patients with known or suspected coronary disease. [ABSTRACT FROM PUBLISHER]

Background: It is generally perceived that the persistence of ST segment depression for more than 5 min after treadmill exercise testing (ETT) signifies a strongly positive test and predicts more severe ischemia and coronary artery disease. Aim: The aim of this study was to determine if prolonged ST segment changes (>5 min) after ETT identifies patients with more severe ischemia and thus severe coronary artery disease. Methods: Twenty five patients (19 males, mean age 58±10 years) with >1 mm ST segment depression and recovery time ≤5 min (group 1) and 25 patients (20 males, mean age 62±10 years) with >1 mm ST segment depression and recovery time >5 min (group 2) undergoing ETT and single photon emission computed tomography were prospectively enrolled. Summed stress and difference scores, stress and reversible extent % of perfusion abnormalities, and lung heart ratio was calculated. Results: There was no significant difference in the mean summed stress score (9±9 versus 13±10, P=0.13), summed difference score (4±3 versus 6±5, P=0.13), stress extent % (14±16 versus 19±13, P=0.13), extent of reversibility % (7±9 versus 7±7, P=0.93), or lung heart ratio (0.48±0.07 versus 0.46±0.07, P=0.50) between the two groups. There was no significant difference in the incidence of severe ischemia (summed difference score >13) in the 2 groups (24% versus 40%, P=0.36). Conclusion: We conclude that utilizing the commonly used cutoff for prolonged ST segment depression: >5 min in recovery, does not identify patients with more severe ischemia or coronary artery disease and, therefore, at increased risk. Thus, it appears unnecessary to give special consideration to these patients by way of prolonged monitoring in recovery, or a more aggressive non-invasive ischemia imaging approach after the ETT. [Copyright &y& Elsevier]

Noninvasive cardiokymography has been further developed to be able to record wall motion abnormalities during exercise. The study was designed to evaluate the diagnostic accuracy of stress cardiokymography and electrocardiography in the diagnosis of coronary artery disease. 223 patients were included in a prospective investigation using a newly developed computerized cardiokymography device. Sensitivity, specificity, and positive predictive value were 61, 69 and 90% for exercise cardiokymography, and 57, 74 and 91% for exercise electrocardiography, respectively. There was no statistically significant difference between cardiokymography and electrocardiography. The combination of electrocardiography and cardiokymography did not produce a significant improvement in diagnostic accuracy in comparison to exercise electrocardiography alone.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Abnormal heart rate (HR) recovery at 1 min after exercise (≤12 beats) was recently suggested to be a predictor of all cause and cardiac mortality. Aim: This study aimed to (1) correlate HR recovery at 1 min after exercise with known exercise and myocardial perfusion markers of increased cardiac mortality, and (2) compare the known exercise and myocardial perfusion markers of increased cardiac mortality between patients with a normal and abnormal HR recovery at 1 min after exercise. Methods: One hundred patients with known or suspected coronary artery disease referred for exercise stress testing (ETT) were prospectively enrolled. Percent, ETT time peak HR, HR reserve, summed stress score (SSS), extent of stress (SE%) and reversible perfusion abnormalities (RE%) were recorded in every patient. Results: There was poor correlation with markers of myocardial ischemia or infarction [SSS (r = 0.15), SE% (r = 0.05), RE% (r = 0.12), all p = n.s.] but highly significant correlation between HR recovery at 1 min after exercise and chronotropic variables [ETT time (r = 0.56), peak HR (r = 0.65), HR reserve % (r = 0.64), all p < 0.001]. Patients on β-blockers had significantly more incidence of an abnormal HR recovery at 1 min after exercise, compared to patients not on β-blockers (88 vs. 56%, p < 0.01). Conclusion: Abnormal HR recovery at 1 min after exercise has no correlation with known myocardial perfusion markers of increased cardiac mortality. Patients with an abnormal HR recovery do not appear to have an increased incidence or more severe myocardial infarction or ischemia. However, there is a strong correlation between HR recovery at 1 min after exercise and the chronotropic variables during exercise.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Myocardial perfusion imaging (MPI) with technetium-99m-labeled sestamibi and exercise electrocardiography (EECG) are widely used for risk stratification of patients with known or suspected coronary artery disease (CAD). However, no large-scale studies have addressed the prognostic power of the combined information from these diagnostic tools.Methods and Results: We studied 697 consecutive patients who underwent a 2-day Tc-99m sestamibi cardiac perfusion imaging protocol. The EECG was performed on a bicycle ergometer by symptom-limited exercise. Causes of death were obtained from death certificates. Univariate survival analyses were performed with a Kaplan-Meier estimate and a corresponding log-rank test. A multivariate Cox proportional hazards model was applied to test for potential predictor covariates obtained from hospital records. The predominant risk factors of cardiac death were fixed perfusion defects (relative risk, 2.55; range, 1.43 to 4.55) and an impaired circulatory exercise response (relative risk, 3.26; range, 1.74 to 6.08). The major prognostic information of MPI was the ability to detect patients with a definitively low risk. Patients with impaired circulatory response to exercise test and fixed perfusion defects were at a very high risk.Conclusion: The combined results of MPI and EECG provide substantial information on the long-term risk of cardiac death in patients with suspected CAD. [ABSTRACT FROM AUTHOR]

The response to a standardized angina and infarction questionnaire, the occurrence of coded resting and postexercise ECG findings suggestive of coronary heart disease (CHD), and blood pressure were studied among 417 male Japanese and 237 Finnish workers exposed occupationally to carbon disulfide (CS) and their controls, 391 Japanese and 233 Finnish men without such exposure. All of the subjects were aged 35 to 54 years. Among the Japanese subjects only seven exposed and one unexposed worker had a history of angina; typical angina was present in two exposed and in none of the unexposed men; and one had a history of possible myocardial infarction. In the Finnish exposed and unexposed groups the prevalence were 15 and 10% for total angina, and 4 and 4% for typical angina, respectively. No impressive differences emerged in the prevalences of 'coronary' ECG items between the exposed and unexposed groups. The presence of 'coronary' ECG findings was no more frequent in those with a history of angina than in those workers without such findings. None of the exposed and unexposed Japanese subjects with 'coronary' ECG changes gave history of angina or infarction. The 'coronary' ECG prevalences for the Finnish exposed and unexposed men were 30 and 24%. If a history of angina together with 'coronary' ECG abnormalities are taken as evidence of probable CHD, the total prevalence among the Japanese was 0 % for both the exposed and the unexposed group; and among the Finns, 5 and 2%, respectively. Smoking history, obesity, and blood pressure showed no marked differences in the Japanese groups. The diastolic and systolic blood pressure were significantly higher among the exposed Finnish workers than among the controls. The study yielded no evidence for an increased occurrence of the examined parameters among the Japanese workers exposed to carbon disulfide, whereas the exposure seemed causally associated with excess angina and high blood pressure among the Finns. The potential CHD induced by CS seemed to be undetectable by means of electrocardiography. [ABSTRACT FROM AUTHOR]

Simultaneous two-channel Holter monitoring, with a direct recording system, and maximal exercise testing with a 12-lead precordial electrocardiographic mapping system were performed in 50 patients with chest pain (41 with documented coronary artery disease, 9 without). The exploring Holter leads were placed to correspond to CM5 and an aVF-like lead. In 36 patients, ST segment changes were found with both Holter and the 12-lead precordial electrocardiogram, while in 12 patients no ischaemic changes were detected by either method. Thus the results of the two methods concurred in 48 of 50 patient (96%). The magnitude of the ischaemic change was similar in 24 of 36 patients (67%), while the Holter system underestimated the ischaemic change by 0.5–2.0 mm in 12 patients. When the maximal ST segment deviation in V5 was compared with CM5, the deviations with both systems were identical in all but one patient in whom a difference of 0.5 mm was found. The use of a Holter lead resembling aVF identified maximal ST segment change on only one occasion, and in only four patients was an ST segment change of 1 mm noted. In conclusion, ambulatory monitoring utilizing only CM5 seems to detect most episodes with ST segment changes, but the use of a 12-lead precordial mapping system during exercise testing may expand the possibility of defining the optimal sites for the exploring Holter leads to detect maximal ST segment change. [ABSTRACT FROM PUBLISHER]

The value of a predischarge exercise test combined with thallium-201 myocardial scintigraphy in detecting patients with severe multivessel disease (MVD) was studied in 58 consecutive patients discharged after a first acute myocardial infarction. Twelve electrocardiographic, clinical and scintigraphic variables were analysed. Angiography at one month revealed MVD (>70% narrowing in vessels unrelated to infarction) in 26 patients (45%). ST segment depression of I mm or greater, thallium defects in multiple vascular distributions (MVTL), and reversible thallium defects in a vascular distribution different from the infarct related vessel predicted patients at risk for MVD (predictive value respectively of 68%, 65% and 75%). The other variables were not significantly associated with the presence of MVD. Only ST segment depression and thallium defects in multiple vascular distributions emerged as independent predictors of MVD. Their combination yielded a 77% sensitivity and a 59% specificity for MVD. Combination of thallium imaging with the predischarge exercise ECG significantly improved the stratification provided by the exercise test alone (P<0.05). A positive thallium scan (MVTldefects) associated with a positive ECG (ST depression) carried a risk for MVD of 80% in the population studied. When both tests were negative, MVD was infrequent (risk 22%). Because improvement in the stratification of patients is not as clear as expectedfrom studies performed at a later stage, it appears that exercise thallium scintigraphy at a submaximal level one or two weeks after infarction does not provide optimal information. Predischarge exercise thallium-201 scintigraphy, however, superior to an exercise tolerance test alone in separating patients into those with high and low risk of MVD. [ABSTRACT FROM PUBLISHER]

Objectives. We addressed the question whether in patients with cardiac chest pain referred for stress myocardial perfusion scintigraphy, Tc-99m MIBI SPECT stress imaging should always be followed by a rest imaging procedure. Background. Using Tc-99m MIBI imaging a stress-rest sequence is usually performed implying that the resting study always follows the stress study irrespective of the results of the stress study. As a normal stress study would eliminate a subsequent resting study, it appears desirable to potentially define certain subsets of patients in whom a normal stress study can be expected in order to determine a more selective referral approach to the nuclear medicine department. The consequences of such a more streamlined approach would less impose on the logistics of the department of nuclear medicine, with decrease of investigation time, radiation dose, and costs in a time of retrenchment in the medical sector. Methods. A consecutive series of 460 patients (mean age 58.2 years) was studied who were stratified to 269 patients without prior myocardial infarction, and to 191 patients with documented evidence of a previously sustained mycoardial infarction. All patients underwent Tc-99m MIBI SPECT imaging according to a two-day stress-rest protocol. Results. Patients with and without a previous myocardial infarction showed suboptimal overall predictive accuracies for the exercise electrocardiograms (58% and 60%, respectively). In the total group of 460 patients, 94 (20%) patients showed a normal stress-rest Tc-99m MIBI SPECT; this occurred in 86/269 (32%) patients without a previous myocardial infarction and in only 8/191 (4%) patients with a previous myocardial infarction. Conclusions. Patients with a stress defect at Tc-99m MIBI SPECT imaging should always undergo a resting SPECT study irrespective of the clinical and stress electrocardiographic findings. As patients without a previous myocardial infarction had a normal stress SPECT study in almost one-third (32%) of patients compared to only 4% in patients with a previous myocardial infarction, it may be useful to employ different referral and imaging strategies i.e. a stress-only versus a stress-rest procedure. To schedule referring patients differently according to the presence or absence of a previously sustained myocardial infarction may be cost-saving, less demanding for the nuclear medicine personnel, and patient-convenient. In addition, a stress-only imaging procedure reduces radiation exposure to the individual patient. [ABSTRACT FROM AUTHOR]

The effect of coronary artery bypass surgery (CAB) on ventricular arrhythmias (VA) was studied in a prospective investigation involving 32 patients (mean age 54 years) who underwent CAB because of severe stable angina pectoris. Prior to CAB as well as 12 months later each patient was subjected to the following investigational programme: resting ECG, exercise ECG, 24-h ECG, selective coronary arteriography, ventriculography and cardiac catheterization. Exercise ECG showed VA in only three patients. The prevalence of VA during 24-h ECG was 56 and 66% on the two occasions (NS), while complicated VA (multiform, repetitive, R on T) was seen in 18 and 28%, respectively (NS). The persistence (number of 6-h periods showing VA) was 33 and 47% with regard to any VA (P<0.05), while complicated VA occurred in 13 and 15% of the 6-h periods (NS). Except for an increase in dp/dt/P at the postoperative measurement (P<0.05), no significant change in the performance of the left ventricle was seen after CAB though the graft patency was 77%. It is concluded that in patients with ‘medically intractable’ stable angina pectoris, CAB does not effect the occurrence of VA to any great extent — probably because left ventricular function is unchanged one year after as compared with that prior to CAB. [ABSTRACT FROM PUBLISHER]

Ninety-two patients (15 devoid of coronary artery disease, 24 with atherosclerotic coronary lesions but without antecedent myocardial infarction, 20 with prior anterior myocardial infarction, 33 with prior inferior infarction) were submitted to a stress electrocardiogram and thallium201 scan within the three months preceeding or the month following a coronary angiogram. This study first confirmed that by using a segmental analysis of the scans, the localization of the coronary lesion responsible for the appearance of zones of hypofixation can be determined. In general, however, defects appear only in the territory of the most stenosed vessels. For the detection of coronary disease in the absence of antecedent myocardial infarction, the exercise electrocardiogram showed a sensitivity of 54% and a specificity of 67%. The sensitivity (92%) and specificity (93%) of stress myocardial scintigraphy were clearly superior. Stress thallium201 scintigraphy detected 60% of the patients with anterior infarction and multiple vessel disease, but suggested the existence of multiple lesions in three out of five subjects with isolated LAD disease. After inferior infarction, multiple vessel disease was detected by scintigraphy with a sensitivity of 45% and a specificity of 82%. If an apical defect in the anterior view was considered to be the sign of LAD artery stenosis, the sensitivity of stress myocardial scintigraphy for the detection of multiple vessel disease in the presence of inferior myocardial infarction reached 86% and the specificity 54%. Stress thallium myocardial scintigraphy appears more sensitive and specific than exercise electrocardiography for the detection of coronary artery disease and residual ischaemia after myocardial infarction. [ABSTRACT FROM PUBLISHER]

Four dynamic tests of cardiac function were compared in a group of 13 long-standing insulin-dependent diabetics who had no clinical evidence of cardio-respiratory disease. One patient developed abnormal features during 24 hour ambulatory electrocardiograms while all 13 patients had normal exercise electrocardiograms. The change in left ventricular ejection fraction during dynamic supine exercise as measured by gated blood-pool scintigraphy was not significantly different from control subjects (p<0.1) while during cold stimulation testing the change in left ventricular ejection fraction in the diabetics was highly significantly different from the control subjects (p<0.01). Five of the patients had one or more abnormal tests of autonomic function. The cold stimulation test may be a sensitive index of cardiac dysfunction in diabetics but as the mechanism is unclear alternative explanations are possible. While the etiology of heart disease in such patients is uncertain it is likely to be multifactorial and this test may prove useful in investigating the natural history and pathogenesis of cardiac disease in diabetics. [ABSTRACT FROM AUTHOR]

Abstract Various diagnostic methods have been used to evaluate hypertensive patients under physical and pharmacological stress. Several studies have shown that exercise hypertension has an independent, adverse impact on outcome; however, other prognostic studies have shown that exercise hypertension is a favorable prognostic indicator and associated with good outcome. Exercise hypertension may be encountered as a warning signal of hypertension at rest and future hypertensive left ventricular hypertrophy. The results of diagnostic stress tests support that hypertensive response to exercise is frequently associated with high rate-pressure product in hypertensives. In addition to the observations on high rate-pressure product and enhanced ventricular contractility in patients with hypertension, evaluation of myocardial contractility by Doppler tissue imaging has shown hyperdynamic myocardial function under pharmacological stress. These recent quantitative data in hypertensives suggest that hyperdynamic myocardial function and high rate-pressure product response to stress may be related to exaggerated hypertension, which may have more importance than that it has been already given in clinical practice.

Myocardial ischemia (MI) has the highest mortality rate in the world. Traditional noninvasive MI examinations include exercise electrocardiography tests (EETs) and stress echocardiography (SE). Treadmill and dobutamine tests are commonly used as stress protocols. In the present study, 278 patients with suspected MI were examined, 66 of whom were diagnosed with MI and 212 did not show evidence of MI by coronary angiography (CAG)/coronary CT angiography (CCTA). All patients underwent clinical EET and SE evaluations prior to CAG/CCTA. All groups were compared based on specific clinical parameters including age, sex, blood pressure, heart rate, blood oxygen saturation, underlying conditions and ejection fraction/fraction shortening. The data indicated superior diagnostic efficiency of the combined EET+SE method for the diagnosis of suspected MI compared with either EET or SE alone. The sensitivity/specificity/positive predictive value and negative predictive value for detecting MI were excellent compared with those of traditional examinations. The diagnostic efficiency of the combination analysis may reduce the prevalence of MI and medical costs. The present study provided novel insight for the development of methods that may be used for MI detection and prediction., (Copyright: © Huang et al.)

In this study the use of exercise electrocardiography, by 47 general practitioners in South East Kent has been evaluated. Of 110 consecutive requests the majority (88%) were for diagnostic purposes, while only 7% were for prognostic assessment. Many of those referred were young or had non-cardiac chest pain and in 59% of cases the test result was unlikely to alter the clinical assessment of the probability of ischaemic heart disease (IHD). The test result influenced patient management in 85% of cases. Only 15% of patients were subsequently referred to the district general hospital although all had been considered for referral prior to the test. Although referral for invasive investigation of six patients was expedited by the provision of stress testing, in five patients general practitioners failed to consider any further investigation despite the patient having a strongly positive test. General practitioners use exercise electrocardiography primarily to exclude IHD in patients at low risk and provide reassurance. They rarely use the test as a means to guide management of those with known or probable IHD. [ABSTRACT FROM AUTHOR]