Current review of exercise testing: application and interpretation

Exercise testing has changed dramatically in scope over the past 50 years. While initially used to assess functional capacity, it is now also utilized to detect the presence and severity of coronary artery disease (CAD), to evaluate postmyocardial infarction patients at risk for future cardiac events, to screen certain asymptomatic populations for CAD, and to evaluate dysrhythmias, peripheral vascular disease, and lung disease. Dynamic exercise in continuous multistage protocols is most popularly employed because of the more easily measured workload. The safety of exercise testing, its contraindications and termination end points are summarized. The sensitivity of exercise testing ranges between 60 and 70% while specificity has been reported between 85 and 90%. Both sensitivity and specificity are enhanced through use of radionuclide exercise thallium imaging and ventricular angiography.     

Complications of exercise testing: A survey in three German-speaking countries

A survey was carried out of 1 065 923 individual exercise testsperformed at 198 sites in three German-speaking countries. Seventeen deaths were reported among 712 285 patients, in 80%of whom coronary heart disease was either established, suspected,or ruled out. Fatal complications were unrelated to exercisetechnique, attained workload, or selection. The cause of deathin these patients was myocardial infarction; 10 additional non-fatalinfarctions were reported. Among 353 638 young, apparently healthy, athletes, no deathsor life-threatening complications were reported. The most common non-fatal, life-threatening complication wasventricular fibrillation, which occurred at a rate of 1.4 per10 000 tests employing bicycle ergometry. It was not observedamong 83 000 procedures with an arm-assisted step test. In comparison to the results from the United States in the NationalSurvey of Exercise Stress Testing (1980) the mortality ratein Europe appears to be lower (Europe 0.25 per 10 000, U.S.A.0.5 per 10 000). In addition, the total number of severe complicationswas lower in Europe (Europe 1.4 per 10 000, U.S.A. 8.8 per 10000). It is concluded that exercise testing is a relatively safe procedurewhen all possible precautions, including the availability ofa defibrillator, have been taken. The observed differences inthe non-fatal complication rates for various types of exerciserequire further clarification.     

The safety of maximal exercise testing

Previous reports on the safety of exercise testing have been based on surveys from different testing facilities with a variety of testing protocols and patient types. From 1971 through 1987, 71,914 maximal exercise tests conducted in a population with a low prevalence of known coronary heart disease under uniform conditions at a single medical facility resulted in six major cardiac complications including one death. No complications have occurred in the past 10 years in 45,000 maximal tests. The overall cardiac complication rate in men and women is 0.8 complications per 10,000 tests with 95% confidence intervals of 0.3-1.9 complications per 10,000 tests. Maximal exercise testing appears safer than some previously published reports have suggested and seems to be getting safer with time.     

Factors of error in blood pressure readings: A survey of methods of teaching and interpretation

The purpose in the presentation of this problem is to emphasize the need for a universal standardization of the methods used in the measurement of blood pressure. We have made and effort to determine what variations ordinarily occur in the making of blood pressure observations by interns, attending physicians, and postgraduate medical students in a large postgraduate institution; second, to ascertain how this procedure is taught by medical schools; and third, how it is prescribed by other (medical) institutions which are vitally interested in this subject, such as the life insurance companies. No attempt is made to recommend a standardized method of procedure.Throughout the country, the most widely accepted and practiced method of measuring blood pressure is the auscultatory method described by Korotkoff in 1905, with the use of a rubber cuff, attached either to a mercury or aneroid manometer, and a stethoscope. In a critical study of blood pressure readings as recorded in various hospital charts by different attending and house physicians, many discrepancies were found. In fact, there was greater variation than the regular limits of error would allow. This latter finding provided the stimulus for this investigation.It was decided to test the methods employed in taking blood pressure readings by various members of a large general hospital. The New York Post-Graduate Hospital was considered suitable because it is abundantly supplied with physicians from all parts of the world and from many different medical schools. It was decided to make the experiment among three groups: (1) interns, (2) postgraduate students, and (3) attending physicians.     

New parameters in the interpretation of exercise testing in women: QTc dispersion and QT dispersion ratio difference

BACKGROUND: It has been reported that the increase of QT dispersion (QTD) that occurs due to increased inhomogeneity of the ventricular repolarization because of transient ischemia obtained by standard 12-lead electrocardiogram (ECG), the changes during exercise, and the differences between exercise and rest increase the accuracy of exercise test in the diagnosis of coronary artery disease (CAD). HYPOTHESIS: This study was designed to investigate the value of QTD parameters, which are reported to increase the diagnostic accuracy of exercise test in women. METHODS: Ninety-seven women who had undergone coronary angiography and exercise test were evaluated for diagnosis of chest pain. QT dispersion was calculated using the measurements of the highest and lowest values of QT interval obtained by ECG during peak exercise. The QTc using Bazett's equation, and the QTD ratio (QTDR) using QT/RR were calculated, and QTcD and QTD ratios were obtained. The difference between QTcD and QTDR was determined by extracting the rest values from the exercise values. RESULTS: The groups with normal coronaries (n = 48), single-vessel CAD (n = 24), and multivessel CAD (n = 25) were compared. The obtained QTD parameters at peak exercise and their differences between exercise and rest were found to be significantly increased in patients with CAD (p <0.001). Furthermore, these parameters were found to be higher in the patients with multivessel CAD than in those with single-vessel disease (p < 0.05). With the parameters QTcD > 60 ms and QTDR > 10%, greater sensitivity and specificity were obtained compared with ST-segment depression. The highest diagnostic accuracy was obtained with the QTD parameters calculated from the differences between rest and exercise values. The diagnostic accuracy of the difference of QTcD > 15 ms and the difference of QTDR > 5% was relatively higher than the other parameters (sensitivity, specificity, and negative and positive predictor values are 84, 88, 84, 87% and 84, 96, 85, 95%, respectively). CONCLUSION: The use of QTD parameters as variables of ECG, which is easily obtainable in the evaluation of exercise ECG in women, increases the diagnostic accuracy of the exercise test. In addition, the evaluation of QTD variables may provide information about the incidence of CAD.     

The use of exercise testing and other methods in the investigation of dyspnea

The sensation of effort is increased when the tension developed by active muscle is increased or when the muscle is weak; similar factors contribute to the sense of respiratory effort that constitute the symptoms of dyspnea. Exercise testing enables systematic loading of the respiratory muscles to be studied; the components of the ventilatory responses to exercise may be quantified in terms of the pattern and timing of breathing and of inspiratory flow and volume. The associated sensation of respiratory effort may then be related to the tension developed by respiratory muscles and to their strength.     

Haptoglobin testing in hemolysis: Measurement and interpretation

Haptoglobin is primarily produced in the liver and is functionally important for binding free hemoglobin from lysed red cells in vivo, preventing its toxic effects. Because haptoglobin levels become depleted in the presence of large amounts of free hemoglobin, decreased haptoglobin is a marker of hemolysis. Despite its ubiquity and importance, a paucity of literature makes testing difficult to interpret. This review highlights the many physiological roles that have been recently elucidated in the literature. Different methodologies have been developed for testing, including spectrophotometry, immunoreactive methods, and gel electrophoresis. These are covered along with their respective advantages and disadvantages. As there is no single gold standard for hemolysis, validation studies must rely on a combination of factors, which are reviewed in this article. Pitfalls and limitations of testing are also addressed. False positives can occur in improper specimen preparations, cirrhosis, elevated estrogen states, and hemodilution. False negatives can occur in hypersplenism and medications such as androgens and corticosteroids. Haptoglobin testing in the setting of inflammation is additionally discussed as interpretation can be difficult in this setting. Given the widespread use of haptoglobin testing, it is vital that clinicians and laboratory staff understand the principles and correct interpretation of this test. Am. J. Hematol. 89:443–447, 2014. © 2013 Wiley Periodicals, Inc.     

X-linked clonality testing: interpretation and limitations

Clonality often defines the diseased state in hematology. Clonal cells are genetically homogenous and derived from the same precursor; their detection is based on genotype or phenotype. Genotypic clonality relies on somatic mutations to mark the clonal population. Phenotypic clonality identifies the clonal population by the expression pattern of surrogate genes that track the clonal process. The most commonly used phenotypic clonality methods are based on the X-chromosome inactivation principle. Clonality detection based on X-chromosome inactivation patterns (XCIP) requires discrimination of the active from the inactive X chromosome and differentiation of each X chromosome's parental origin. Detection methods are based on detection of X-chromosome sequence polymorphisms identified by protein isoforms, transcribed mRNA, and methylation status. Errors in interpreting clonality tests arise from stochastic, genetic, and cell selection pressures on the mechanism of X inactivation. Progressive X-chromosome skewing has recently been suggested by XCIP clonality studies in aging hematopoietic cells. This has led to new insights into the pathophysiology of X-linked and autoimmune disorders. Other research applications include combining XCIP clonality testing with genetic clonality testing to identify clonal populations with yet-to-be-discovered genetic changes.     

Feasibility and safety of early exercise testing using the Bruce protocol after acute myocardial infarction

OBJECTIVE: To assess the feasibility and safety of exercise testing (ET) using a Bruce protocol (BPR) within three days of an acute myocardial infarction (AMI) with the data obtained from a prospectively managed database. BACKGROUND: Exercise testing after AMI is usually done between days 4 and 6 and often using a "low-level" protocol. Earlier testing with BPR may allow for efficient triage. METHODS: Patients were considered for early ET when off intravenous nitroglycerine with no rest angina, uncontrolled cardiac failure or arrhythmias. RESULTS: Of 300 consecutive AMI patients who underwent an ET, 216 (72.0%; M = 163, F = 53; age mean 59 +/- 0.8 SEM, range 34 to 83 years) had ET within three days of admission. There were 124 (57%) negative, 56 (26%) positive and 36 (17%) indeterminate tests. The maximum heart rate achieved was 116 +/- 1 beats/min (range 64 to 163), which was 72.2 +/- 0.8% of predicted maximum (86.6% on beta-adrenergic blocking agents at ET; exercise duration = 6.7 +/- 0.2 min). Reasons for termination: maximum effort-89 (41%); low-level test target (stage III/IV of BPR)-63 (29%); positive ST segment change-19 (9%); severe chest pain-12 (5.5%); reaching 90% predicted maximum heart rate-6 (3%); nonsustained ventricular tachycardia-1 (0.5%); other-26 (12%). Fourteen (6.5%) patients had minor complications (i.e., drop in systolic pressure, chest pain >5 min) with no cardiac arrests, AMIs or deaths. After the ET, 87 (40%) patients were discharged the same day, 73 (34%) the next day. CONCLUSIONS: The majority of ETs after an AMI can be done using the Bruce protocol within three days of admission with a very low incidence of complications. This can lead to early triage and potential cost savings.     

A survey of the accuracy of interpretation of intraoperative cholangiograms

Objectives: There are few data in the literature regarding the ability of surgical trainees and surgeons to correctly interpret intraoperative cholangiograms (IOCs) during laparoscopic cholecystectomy (LC). The aim of this study was to determine the accuracy of surgeons' interpretations of IOCs. Methods: Fifteen IOCs, depicting normal, variants of normal and abnormal anatomy, were sent electronically in random sequence to 20 surgical trainees and 20 consultant general surgeons. Information was also sought on the routine or selective use of IOC by respondents. Results: The accuracy of IOC interpretation was poor. Only nine surgeons and nine trainees correctly interpreted the cholangiograms showing normal anatomy. Six consultant surgeons and five trainees correctly identified variants of normal anatomy on cholangiograms. Abnormal anatomy on cholangiograms was identified correctly by 18 consultant surgeons and 19 trainees. Routine IOC was practised by seven consultants and six trainees. There was no significant difference between those who performed routine and selective IOC with respect to correct identification of normal, variant and abnormal anatomy. Conclusions: The present study shows that the accuracy of detection of both normal and variants of normal anatomy was poor in all grades of surgeon irrespective of a policy of routine or selective IOC. Improving operators' understanding of biliary anatomy may help to increase the diagnostic accuracy of IOC interpretation.     

On the interpretation of the exercise test

The widespread popularization of stress testing and the extensive application of its results in a variety of clinical settings make it imperative that a better method than the presently used simplistic "positive" or "negative" interpretation be devised. As a step toward a comprehensive diagnostic and prognostic index based on stress tests, a simple grading system of electrocardiographic changes, together with recognition of clinical modifiers, is suggested.     

Statement on cardiopulmonary exercise testing in chronic heart failure due to left ventricular dysfunction: recommendations for performance and interpretation Part II: How to perform cardiopulmonary exercise testing in chronic heart failure.

Basic and practical information related to equipment, methodology, exercise protocols, conduct of the test and quality control issues for cardiopulmonary exercise testing (CPET) will be addressed in this II part of the statement. CPET users have the responsibility for assuring that measurements remain accurate. CPT, especially when it features breath-by-breath gas exchange analysis, requires meticulous attention to calibration procedures to assure accurate and reproducible measurements. Skills and knowledge of personnel for supervision and test interpretation, as well as patient preparation and information are key features for a correct CPET conduction: all these issues will be faced. Finally, after the test, the investigator needs to format the results in a manner that optimises the ability to discriminate essential response features; that is, to establish 'interpretive clusters' of the variables of interest. An example of a cardiopulmonary summary exercise test data report will be provided, defining the most important information that should be incorporated in a final report.     

A survey of exercise beliefs and exercise habits among people with arthritis

Objective . To explore a possible explanation for the problem of why few people exercise despite the positive health advantages, by examining the relationship between exercise beliefs and participation in exercise activities. Methods . Eighty-one respondents aged 27–80 were recruited from 3 Chicago-area health care facilities to complete the study survey; 68 (84%) did so. Participants were asked about their participation in 6 types of exercise activities; they also reported their beliefs concerning their ability to exercise (self-efficacy for exercise), barriers to exercise, benefits of exercise, and the impact of exercise on their arthritis. Results . Study results indicate that belief in the benefits of exercise and self-efficacy for exercise are associated with participation in exercise activities. Also, severity of disease differentiated exercisers from non-exercisers. Conclusions . Results suggest the importance of finding ways to strengthen belief in the benefits of exercise and self-efficacy for exercise in people with arthritis, particularly people with moderate to severe disease-related limitations.     

Original research: Attitudes to radiation safety and cholangiogram interpretation in endoscopic retrograde cholangiopancreatography (ERCP): a UK survey

BackgroundFluoroscopy during endoscopic retrograde cholangiopancreatography (ERCP) exposes staff and patients to potentially harmful ionizing radiation. We performed a UK survey to explore trainee and trainer attitudes to radiation protection and cholangiogram interpretation in ERCP.MethodsAn electronic 10-point survey was prospectively distributed to endoscopy unit leads, training programme directors between October and November 2019. Only UK-based ERCP trainees and trainers with hands-on procedural exposure were eligible for the survey.ResultsThe survey was completed by 107 respondents (58 trainees and 49 trainers), with an estimated overall response rate of 46%. Overall, 49% of respondents were up to date with their radiation protection course, 38% were aware of European Basic safety standards directive (BSSD), 38% wore radiation protection goggles, and 40% were aware of the average radiation screening dose per ERCP procedure. Compared with trainers, trainees were less likely to routinely wear thyroid protection shields (76% vs 92%; p=0.028), have awareness of the BSSD (20% vs 49%; p=0.037) or know their average procedural radiation dosages (21% vs 63%; p<0.001). With regard to cholangiogram interpretation, only 26% had received formal training, with 97% of trainees expressing a desire for further training.ConclusionThis survey highlights a relative complacency in safety attitudes to radiation protection during ERCP. These data provide impetus to improve training and quality assurance in radiation protection, which should be regarded as a mandatory safety aspect prior to commencing hands-on ERCP training.