Accurate detection of coronary artery disease by integrated analysis of the ST-segment depression/heart rate patterns during the exercise and recovery phases of the exercise electrocardiography test

In this comparative cross-sectional study, we evaluated whether a novel computerized diagnostic variable, ST-segment depression/heart rate ST/HR analysis during both the exercise and postexercise recovery phases of the exercise electrocardiography (ECG) test, can detect coronary artery disease more accurately than methods using either exercise or recovery phase alone. The study population comprised 347 clinical patients referred for a routine bicycle exercise ECG test at Tampere University Hospital, Finland. Of these, 127 had angiographically proven coronary artery disease, whereas 13 had no coronary artery disease according to angiography, 18 had no perfusion defect according to technetium-99m sestamibi single-photon emission computed tomography, and 189 were clinically normal with respect to cardiac diseases. For each patient, the maximum values of the ST/HR hysteresis, ST/HR index, end-exercise ST depression, and recovery ST depression were determined from the Mason-Likar modification of the standard 12-lead exercise electrocardiogram [aVL, aVR, and V1 excluded]. The diagnostic performance of these continuous diagnostic variables was compared by means of receiver-operating characteristic analysis. The area under the receiver-operating characteristic curve of the ST/HR hysteresis was 89%, which was significantly larger than that of the end-exercise ST depression (76%, p < or = 0.0001), recovery ST depression (84%, p = 0.0063), or ST/HR index (83%, p = 0.0023), indicating superior diagnostic performance of the ST/HR hysteresis independent of the partition value selection. In conclusion, computerized analysis of the HR-adjusted ST depression pattern during the exercise phase, integrated with the HR-adjusted ST depression pattern during the recovery phase after exercise, can significantly improve the diagnostic performance and clinical utility of the exercise ECG test for the detection of coronary artery disease.     

The importance of adequate exercise in the detection of coronary heart disease by radionuclide ventriculography

Rest and exercise radionuclide ventriculograms were obtained on 77 symptomatic patients without prior documented coronary artery disease (CAD). Coronary artery disease was present by angiograms in 48. Radionuclide ventriculography (RNV) was abnormal in 41 patients (overall sensitivity 85%). In 29 patients with normal coronary arteries, RNV was normal in 24 (specificity 83%). To determine if the exercise level affects sensitivity, the studies were graded for adequacy of exercise. It was considered adequate if patients developed (a) chest pain, or (b) ST segment depression of at least 1 mm, or (c) if they achieved a pressure rate produce greater than 250. Among the 48 patients with coronary artery disease, 35 achieved adequate exercise. Thirty-three had an abnormal RNV (sensitivity 94%). In 13 patients who failed to achieve adequate exercise, RNV was abnormal in eight (sensitivity of only 62%). Some patients with coronary artery disease may have a normal ventricular response at inadequate levels of stress.     

Metabolic changes during exercise testing of patients with ischaemic heart disease

The applicability of a complement consumption assay as a means by which to detect IgG aggregates and immune complexes in serum was examined. Both heavy (greater than or equal to 19S) and intermediate (11-17S) IgG aggregates were detected and the sensitivity of the assay was greater than or equal to 10 mug aggregated IgG/ml. BSA anti-BSA complexes, formed in slight antibody excess, were detected at a BSA concentration of 200 ng/ml. NHS stored at 4degreesC for greater than or equal to 2-3 weeks or at -20degreesC for more than 3 months developed distinct anticomplementarity (AC). This background AC, due to IgG aggregate formation, was reduced by heating the serum at 56degreesC for 50 min prior to testing. A similar reduction of AC and C1q fixation was observed when IgG aggregated at 61degreesC or 63degreesC was heated further at 56degreesC for 50 min. The abatement of AC could not be correlated to a change in IgG aggregation size. In contrast, AC of preformed antigen-antibody complexes was not reduced by this heat treatment.     

Accuracy of heart rate-adjusted ST segments in populations with and without posttest referral bias

We compared the accuracy of the ST segment/heart rate (STHR) index and slope to standard criteria (> or =1 mm horizontal/downsloping ST-segment depression at J + 60 msec) in 1358 patients (152 underwent angiography). All exercise tests used the Cornell protocol and computer measurements of maximum ST-segment depression at J + 60 msec. Test accuracy was determined for the entire group with a probability-based method. Thresholds with equal specificity to standard criteria were determined. By using only patients who underwent angiography, neither STHR index nor slope was more accurate than standard criteria (maximum sensitivity: standard criteria, 42%; STHR index, 51%; STHR slope, 40%). However, by using the entire group, both STHR index and slope were more accurate than standard criteria, but only STHR index achieved statistical significance (maximum sensitivity: standard criteria, 31%; STHR index, 60%; STHR slope, 47%). We conclude that heart rate-adjusted ST-segment criteria are more accurate than standard ST-segment criteria. A lack of demonstration of improved accuracy of STHR index and slope only occurs in patients affected by posttest referral bias.     

Myocardial perfusion SPET in the detection of coronary artery disease in orthotopic heart transplantation

BACKGROUND: Thallium-201 (201Tl) reinjection after conventional redistribution imaging is a standard procedure, resulting in enhanced 201Tl redistribution which is compatible with viable myocardium. Although this method significantly improves identification of viable myocardium, it increases the investigation time by approximately 1 h. Thus, this technique is suboptimal from the standpoint of patient convenience, since its routine performance may be impractical in a high-volume nuclear medicine laboratory. HYPOTHESIS: This study was undertaken to evaluate the efficacy of an early 201Tl reinjection and imaging protocol in combination with sublingual nitroglycerin, to detect myocardial ischemia and/or viability, and to reduce the need for conventional (4 h) redistribution imaging. MATERIALS AND METHODS: In this study, 62 consecutive coronary patients, referred for the detection of possible myocardial ischemia and/or viability, were involved (mean age 55 years, range 41-70). Of those, 50 had previous angina attacks, with 42 having a history of previous myocardial infarction; 10 patients had coronary artery bypass grafting; and the remaining 2 had atypical chest pain. Immediately after the completion of the initial postexer-cise imaging, 0.3 mg sublingual nitroglycerin followed by the reinjection of 1 m Ci of 201Tl were administered, and two further sets of images were acquired 1 h and 4 h later. RESULTS: In each set of images, a total of 496 segments were analyzed. On postexercise imaging, 305 (61%) segments demonstrated defects of which 198 (65%) showed enhanced thallium uptake, 97 (32%) did not change, and 10 (3%) showed reverse redistribution on 1 h reinjection imaging (IRI). Of the 97 persistent defects, only 17 (6%) showed fill-in of 201Tl on 4 h redistribution imaging (CRI), while 12 (4%) segments showed reverse redistribution. On the other hand, after analyzing the 62 patients of the 1 h IRI, 17 (27%) remained unchanged while in only 1 patient (6%) of 17 the diagnosis changed from myocardial necrosis to ischemia after analysis of the 4 h CRI. CONCLUSION: These results indicate that early postexercise reinjection of 201Tl in combination with sublingual nitroglycerin followed by 1 h image acquisition may prove useful for a comprehensive and convenient assessment of myocardial ischemia and/or viability.     

Ischemia-associated intraventricular conduction disturbances during exercise testing as a predictor of proximal left anterior descending coronary artery disease

To determine the incidence and significance of transient intraventricular conduction abnormalities occurring in association with myocardial ischemia during exercise testing, the recordings of 2,200 consecutive exercise tests were reviewed. Ten patients (0.45%) were identified as having both ischemia and intraventricular conduction abnormalities that developed transiently during the exercise test. In all 10 patients both typical angina and electrocardiographic evidence of ischemia developed during exercise. Among the 10 patients, left anterior hemiblock developed in 4, left posterior hemiblock in 2, right bundle branch block (RBBB) in 2, RBBB with left axis deviation in 1, and left anterior hemiblock progressing to complete left bundle branch block (LBBB) in 1. All 10 patients had cardiac catheterization showing significant obstruction of the left anterior descending (LAD) coronary artery at or before the origin of the first septal branch. Eight patients were treated surgically and 2 medically, all with relief of ischemic symptoms. Nine of the 10 had repeat exercise stress testing without angina or electrocardiographic evidence of ischemia and without recurrence of the transient intraventricular conduction disturbance. It is concluded that the development of transient intraventricular conduction abnormalities associated with myocardial ischemia during exercise testing is an uncommon occurrence (0.45%). When such conduction disturbances do develop, the existence of significant disease in the proximal portion of the LAD coronary artery is strongly suggested. With control of myocardial ischemia, the transient conduction disturbances during exercise are ameliorated.     

Two dimensional echocardiographic analysis of wall motion abnormalities during handgrip exercise in patients with coronary artery disease

Studies were made of the feasibility and value of two dimensional echocardiography in detecting left ventricular asynergy during handgrip exercise in 45 patients with suspected coronary artery disease. Resting echocardiography revealed normal wall motion in 32 patients, and in 17 of these handgrip exercise induced abnormal wall motion. All 17 patients had significant stenoses in the coronary arteries. However, only 65 percent of patients with coronary artery disease whose resting two dimensional echocardiogram revealed normal wall motion showed abnormal wall motion during handgrip exercise. The left ventricular wall visualized in the short axis plane was divided into 5 segments, and a total of 225 segments were analyzed. Of 49 segments with exercise-induced asynergy, 46 (94 percent) reflected significant stenosis in the perfusing coronary artery. In particular, 16 (89 percent) of 18 segments with exercise-induced akinesia reflected stenosis of greater than 90 percent. Resting or exercise two dimensional echocardiography (or both) was able to diagnose multivessel disease with a predictability of 92 percent. It is concluded that two dimensional echocardiography combined with handgrip exercise has high specificity in detecting coronary artery disease and would be useful for predicting severely stenotic or multivessel coronary arterial lesions.     

Stress testing for coronary artery disease in the elderly

The elderly constitute an increasing percentage of patients evaluated and treated for coronary artery disease. Clinical and noninvasive evaluation are important in both the diagnosis and prognosis of coronary disease in the elderly, and stress testing is an important part of that evaluation. For older individuals capable of vigorous treadmill or cycle exercise, the exercise electrocardiogram, either alone or combined with radionuclide or echocardiographic imaging, remains an excellent diagnostic and prognostic tool. For the large percentage of elderly patients unable to perform adequate exercise, pharmacologic stress testing with dipyridamole, adenosine, or dobutamine is a valuable alternative. The clinician's challenge is to choose the most appropriate cardiac stress test for his or her patient from among the many alternatives available. Future studies comparing the accuracy and cost-to-benefit ratio of various stress tests with regard to the elderly will help achieve this goal.     

Attitudes about treatment of coronary heart disease among women and men presenting for exercise testing

In recent years, several potent gonadotropin-releasing hormone (GnRH) analogues have become available for female contraception and one of them (buserelin) has been tested in lactating women. However, the possible effects on infants due to the transference of the analogue through breast milk have not been studied. The present work evaluated the effect of oral buserelin on urinary LH secretion in male infants. A total of 19 healthy full-term boys (aged 2-4 months) were included in the study. Infants received orally a single dose of a GnRH agonist mixed with breast milk. Urine samples were collected prior to, and 4-6 and 24 h after treatment for LH measurement. The results disclosed a significant increase in LH urine level in the sample taken 4-6 h after buserelin administration. Twenty-four hours after GnRH agonist ingestion, the LH level returned to baseline level. The present study demonstrated that GnRH analogue administered orally to infants escapes from gastrointestinal inactivation and induces a significant rise in LH levels 4-6 h after treatment.     

Clinical yield and cost of exercise treadmill testing to screen for coronary artery disease in asymptomatic adults

The authors present the results of a study carried out within the context of a diagnosis of the state of dental health among 300 twelve years old students in school in the province of Kadiogo (Burkina Faso). The data collected by questionnaires explore the range of behaviours linked to dental health: dental hygiene, eating habits, use of fluoride and use of dental health services. Half of students report that they brush their teeth at least once a day. Among them, there are 2 girls out of three, and one boy out of two. For half of the children, their mothers are the main people who teach them how to brush their teeth. For three children out of four, a tooth brush and tooth paste are the most common methods. Roughly 17% understand the usefulness of fluoride and 70% have never heard of it. Four children out of five consume sugared drinks on a daily basis. 85% say they have never been to the dentist. The information collected could serve as a base for the development and implementation of health promotion and education programmes for dental health within schools.     

Comparison of dobutamine stress echocardiography and treadmill exercise electrocardiography for detection of coronary artery disease

BACKGROUND: Critical analysis of treadmill exercise testing (TMET) for the detection of coronary artery disease has revealed many shortcomings. Excellent diagnostic accuracy has been reported for dobutamine stress echocardiography (DSE). METHODS: A prospective comparison of DSE and TMET for the detection of coronary artery disease in routine clinical practice was performed using contrast cineangiography (significant stenosis > or = 50%) as a gold standard. RESULTS: A total of 116 patients (82 men, 34 women) were studied. Significant stenosis was detected by coronary angiography in 92 patients (79%). Single vessel disease occurred in 28, double-vessel disease in 32, and multivessel disease in 32 patients. Although sensitivity of DSE was better than that of TMET (82 versus 40%), specificity was worse (63 versus 79%). Positive predictive values for both DSE and TMET were good at 89 and 87%, respectively, whereas negative predictive values were poor for both (47% for DSE, 26% for TMET). CONCLUSIONS: Overall, DSE performs better than TMET in terms of sensitivity and positive and negative predictive value. Its lower specificity than that of TMET may lead to more patients being referred for diagnostic coronary angiography. The poor negative predictive value of DSE and TMET means that one should not be falsely reassured by normal results.     

ST segment changes in the ECG. Anesthesia induction with propofol, etomidate or midazolam in patients with coronary heart disease

Induction of anaesthesia with propofol and fentanyl can lead to marked reductions in mean arterial pressure (MAP) and heart rate (HR). Thus, the application of propofol in patients with severely reduced coronary artery perfusion is controversial. METHODS. The study group consisted of 60 patients undergoing coronary artery bypass grafting (CABG). Anaesthesia was induced over 30 s with propofol (P 1.5 mg/kg), etomidate (E 0.3 mg/kg), or midazolam (M 0.15 mg/kg) following a bolus dose of fentanyl (5 micrograms/kg). Vecuronium was used as a muscle relaxant. During induction we continuously measured MAP and HR and recorded the occurrence of myocardial ischaemia using an automatic ST-segment analyser (Marquette 7010). ST-segment deviations of more than 1 mm in leads II and V5 were interpreted as significant signs of myocardial ischaemia. RESULTS. All groups showed reductions in MAP and HR on induction that were marked in the P group. Intubation caused elevation of MAP and HR to pre-induction levels (HR: all groups) or slightly above (MAP: E, M). Four patients in the P group and 3 in each other group showed significant ST-segment deviation prior to induction. In the P group these deviations disappeared in 2 patients after injection while they remained unchanged in the M group. In the E group injection had no effect on the ischaemic ECG changes but produced another case of significant ST-segment deviation. Laryngoscopy and intubation produced no further significant ST-segment deviation in either group. DISCUSSION. Induction is a critical phase of anaesthesia, especially in patients with limited coronary reserve. Induction agents should alleviate the stress response while causing minimal haemodynamic changes. Despite marked reductions in MAP in the P group, the number of patients with ischaemic ECG changes was cut by half. Their number was unchanged or even raised in the other groups. After application of P, with an alleged reduction of coronary perfusion, a compensational reduction in myocardial oxygen consumption may occur.     

Improved detection of coronary artery disease by exercise electrocardiography with the use of right precordial leads

BACKGROUND: Exercise electrocardiography is an perfect test for the detection of coronary artery disease. We attempted to improve the diagnostic accuracy of exercise testing as a noninvasive method for the detection of coronary artery disease by using a combination of the left and right precordial leads. METHODS: We studied 245 patients (218 men and 27 women) ranging from 32 to 74 years of age (mean [+/-SD], 52+/-8) who underwent treadmill exercise testing, thallium-201 scintigraphy, and coronary arteriography. During exercise testing, each patient had one electrocardiogram recorded with the standard 12 leads and 3 right precordial leads (V3R, V4R, and V5R), with the results for each set of leads recorded and analyzed separately. RESULTS: On the basis of coronary arteriography, 34 patients had normal coronary arteries, 85 had single-vessel disease, 84 had two-vessel disease, and 42 had three-vessel disease. The sensitivities of the standard 12-lead exercise electrocardiogram, exercise electrocardiography incorporating right precordial leads, and thallium-201 scintigraphy were 52 percent, 89 percent, and 87 percent, respectively, for the detection of single-vessel disease; 71 percent, 94 percent, and 96 percent for the detection of two-vessel disease; 83 percent, 95 percent, and 98 percent for the detection of three-vessel disease; and 66 percent, 92 percent, and 93 percent for the detection of any coronary artery disease. The specificities of the three methods for the detection of any coronary artery disease were 88 percent, 88 percent, and 82 percent, respectively. CONCLUSIONS: Use of right precordial leads along with the standard six left precordial leads during exercise electrocardiography greatly improves the sensitivity of exercise testing for the diagnosis of coronary artery disease.     

Increased platelet sensitivity toward platelet inhibitors during physical exercise in patients with coronary artery disease

Generalized atherosclerosis and coronary artery disease (CAD) are associated with endothelial dysfunction and during acute myocardial ischemia platelet activation has been reported. Activated platelets exert activated fibrinogen receptors (GP IIb/IIIa) and express CD 62p being regarded as reliable marker for platelet activation. Patients with angiographically proven CAD performed a bicycle exercise test until the onset of angina or ST-segment depression. We studied the ischemia-induced alterations in fibrinogen binding to activated platelet GP IIb/IIIa receptors and CD 62p expression. Therefore, the basal fibrinogen binding to GP IIb/IIIa and CD 62p expression and the thrombin-concentration for half-maximal platelet activation before and after exercise testing were determined. Additionally, inhibition of thrombin-induced platelet activation by increasing concentrations of the prostacyclin-analog iloprost and the NO-donor SIN-1 was examined. In patients with CAD, a significantly reduced basal activation and a highly significant reduction in sensitivity towards thrombin was measured. The thrombin-induced expression of GP IIb/IIIa and CD 62p was significantly diminished in patients with CAD after physical exercise and their platelets were significantly more sensitive towards the inhibitory effects of iloprost and SIN-1. These data demonstrate a significant reduction in platelet activation in response to physical exercise in patients with CAD and advanced atherosclerosis. Despite exercise induced myocardial ischemia as evidenced by angina and ECG-changes, the platelets are not generally activated, as it could be expected. Thus, patients with myocardial ischemia experienced a reduced platelet activity and enhanced sensitivity towards prostacyclin (PGI2) and nitric oxide, probably due to an augmented release of endogenous platelet inhibitory mediators.     

The synergistic effect of smoking and serum cholesterol on coronary heart disease.

Reviews the evidence of a synergistic interaction effect of smoking and elevated serum cholesterol on coronary heart disease (CHD) morbidity and mortality. Methodological issues involved in assessing smoking status, serum cholesterol, and CHD are discussed, and evidence is presented to support the notion that, in part, serum cholesterol, like smoking, is an index of a behavioral risk factor. Such a synergistic interaction is determined to exist, although improvements in methodology are needed to more clearly identify its magnitude. Studies demonstrating that serum cholesterol can be modified by dietary changes and studies exploring the interaction between smoking and cholesterol are evaluated. Possible mechanisms by which smoking and cholesterol may interact to produce CHD are considered. It is suggested that, if smoking cessation and dietary modification behavioral treatments are focused specifically on young and middle-age Americans who smoke and have elevated serum cholesterol, such treatments may increase their effectiveness in lowering the risk of CHD (benefit) without necessarily increasing their effort (cost). (5 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A quantitative analysis of the relationship between the Cook-Medley Hostility Scale and traditional coronary artery disease risk factors.

One possible explanation for the association between Cook-Medley Hostility Scale (Ho Scale; W. W. Cook & D. M. Medley, 1954) scores and premature coronary artery disease (CAD) morbidity and mortality is that hostile persons also have elevations on CAD risk factors. Meta-analyses with fixed and random-effects models were used to evaluate the relationship between Ho Scale scores and CAD risk factors in the empirical literature. Ho Scale scores were significantly related to body mass index, waist-to-hip ratio, insulin resistance, lipid ratio, triglycerides, glucose, socioeconomic status (SES), alcohol consumption, and smoking. Although there was also heterogeneity among study outcomes, the results of conservative random effects models provide confidence in the obtained relationships. On the basis of available evidence, researchers might give attention to obesity, insulin resistance, damaging health behaviors, and SES as potential contributing factors in understanding the association between Ho Scale scores and CAD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ischemic heart disease in the elderly: the role of coronary angioplasty and coronary artery bypass grafting

Management of ischemic heart disease in the elderly is complex. Invasive therapies such as percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) are associated with significant morbidity and mortality. The short-term advantage of PTCA is that its associated noncardiac morbidity and mortality are less than that of CABG, particularly in the incidence of stroke. Unfortunately, PTCA revascularization is less complete and less durable than CABG revascularization. The advantages of CABG are that cardiac revascularization is more complete, the result is more durable, and long-term results are improved over those of PTCA. Conversely, the initial morbidity and mortality are higher for CABG and are adversely affected by factors such as recent myocardial infarction, lung disease, and renal failure. We provide an overview of the results and outcomes of PTCA and CABG in the elderly, as well as suggestions for management.