The exercise electrocardiogram: Differences in interpretation

Blackburn, Henry; Blomqvist, G.; Freiman, Alvin H.; Friesinger, Gottlieb C.; Hornsten, Tom R.; Jackson, L. K.; LaMonte, Charles S.; Lester, Martin; Most, Albert S.; Mason, Robert E.; Mazzarella, John A.; McNalley, Michael C.; Rosner, Stuart; Sheffield, L T; Simonson, Ernst; Doyle, Joseph T.; Fox, Samuel M.; Gubner, Richard; Haskell, William L.; Hellerstein, Herman K.; Rautaharju, Pentti M.; Reeves, Tim

doi:10.1016/0002-9149(68)90305-6

Cited by 69 publications

(12 citation statements)

References 4 publications

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“…However, wide individual variation in interpretation of the ST segment responses occurs, even when experts assess the ECG manually (Blackburn 1968). From this point of view automatic measurement of the ST segment level by computer technology and the methods which our system uses can avoid this kind of error.…”

Section: Discussionmentioning

confidence: 99%

A high-pass phaseless filter for eliminating low-frequency ECG noise during exercise and its clinical application to automatic analysis of the heart rate and ST segment level.

Ino-Oka

Isoyama

Shimizu

et al. 1984

Tohoku J. Exp. Med.

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Section: Discussionmentioning

confidence: 99%

A high-pass phaseless filter for eliminating low-frequency ECG noise during exercise and its clinical application to automatic analysis of the heart rate and ST segment level.

Ino-Oka

Isoyama

Shimizu

et al. 1984

Tohoku J. Exp. Med.

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“…Some of these are: the number of ECG channels to process (3)(4)(5)(6), the number of other channels (2-5 channels for pulse waves, heart sounds and respiratory signals), the sample interval (usually 2 msec) and the duration of each sample period (usually 20 set). The next overlay performs the CALIBRATION of the analog input beats is performed.…”

Section: Appendixmentioning

confidence: 99%

“…It also has a prognostic value for the development of ischemic heart disease in otherwise asymptomatic subjects (4,5). However, the interobserver variation in the visual interpretation of exercise ECG's is large (6). This is caused in part by the amount of noise present in the signal and in part by the different criteria employed for classification.…”

mentioning

confidence: 99%

On-line processing of orthogonal exercise electrocardiograms

Simoons

Boom

Smallenburg

1975

Computers and Biomedical Research

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A special program has been developed for on-line processing of orthogonal electrocardiograms during exercise with a small computer system. Special measures were taken to obtain high measurement accuracy and to prevent errors due to baseline drift, skeletal muscle noise or premature beats. The program was tested on exercise electrocardiograms from 47 normal men and 50 patients with coronary artery disease. Single representative complexes were obtained by averaging of beats selected with the aid of the spatial velocity time function of the QRScomplex and the STsegment. The method used is comparable to, but faster than, cross correlation of the spatial velocity time functions. The onset and end of the QRS complex during exercise were determined using templates derived from the first record of the particular subject. This algorithm resulted in a lower measurement error than other methods for waveform analysis.Depression of the ST segment of the electrocardiogram (ECG) recorded during exercise in subjects with a normal ECG at rest is considered to be a specific in,dication for the presence of myocardial &hernia (1, 2, 3). It also has a prognostic value for the development of ischemic heart disease in otherwise asymptomatic subjects (4,5). However, the interobserver variation in the visual interpretation of exercise ECG's is large (6). This is caused in part by the amount of noise present in the signal and in part by the different criteria employed for classification. With digital computer techniques the signal to noise ratio of the ECG and thus the measurement accuracy can be improved. Also multivariate analysis of ECG measurements can now be performed. It is therefore to be expected that computer assisted interpretation will improve the diagnostic value of exercise ECG's (7).Averaging of a number of heart beats is often employed to reduce the amount of noise in the ECG caused by skeletal muscle contractions during exercise. However, averaging may cause considerable errors particularly when the time alignment of the beats is not accurate, or when premature beats are present during exercise. Also QRS complexes may be detected erroneously when sudden baseline shifts take place. Special techniques should therefore be employed to avoid these sources of artifacts.In this study a new method is presented for the detection of QRS complexes and for averaging of the exercise ECG. It is based on selection of those QRS complexes and ST segments which have a similar waveform. In addition an improved method

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“…The problem of clinical disagreement also extends to the interpretation of diagnostic tests, as is the case for X-rays and ECGs. When two cardiologists examined the same ECG from 38 patients, a j value of 0.3 was found [12].…”

mentioning

confidence: 99%

“…The overall prevalence of PE was 23%. The studied diagnostic strategy was safe and effective, as assessed by a 3-month thromboembolic risk that was about 1% [12]. To evaluate the effect of age on the performance of these two prediction rules, we arbitrarily divided our population into three age categories: < 50 years, 50-74 years, and ‡ 75 years.…”

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confidence: 99%

Observer variability in the assessment of clinical probability in patients with suspected pulmonary embolism

Leclercq

Kruip

Gillavry

et al. 2004

Journal of Thrombosis and Haemostasis

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5 Nolan TE, Smith RP, Devoe LD. Maternal plasma D-Dimer levels. in normal and complicated pregnancies. Obstet. Gynaecol. 1993; 81: 235. 6 Observer variability in the assessment of clinical probability in patients with suspected pulmonary embolism Assessment of the clinical pretest probability in patients with clinically suspected pulmonary embolism (PE), based on clinical judgement alone (further referred to as Ôclinical probability estimateÕ) or a structured prediction model, in order to guide further diagnostic testing has aroused new interest. Wells and colleagues derived a clinical model based on information from the medical history, physical examination, blood gas analyses, chest X-ray, electrocardiography and the likelihood of an alternative diagnosis [1]. This model was subsequently simplified [1,2]. These models have now successfully been applied in several management studies in patients with suspected PE [3][4][5]. However, the diagnostic accuracy of the clinical probability assessment in previous studies varied significantly [1][2][3][4]6]. The reasons for this observed heterogeneity in test accuracy is not fully explained. An important determinant of test accuracy is its reproducibility, which so far has not been studied. We therefore evaluated the interobserver variability of the original clinical probability assessment using a previously described structured clinical model. In addition, we compared the results of the clinical model with those of the clinical probability estimate in the same patient as assessed by the same physician.The investigation was performed within the framework of a management study in a large teaching hospital, in which the outcome of the clinical probability was used in combination with a D-dimer test to guide further diagnostic and therapeutic management [4]. In consecutive in-and outpatients with clinically suspected PE, clinical probability was assessed by two independent physicians using estimate and a structured clinical model as described by Wells and colleagues (further referred to as Ôextended clinical modelÕ) with the classification of low, moderate or high probability of PE [1]. After completion of the study, the obtained information was used to calculate the result (low, moderate or high and unlikely or likely probability) of the simplified clinical model, as described by Wells and colleagues [2]. The primary analysis was performed in the patient group with a duplicate assessment of the clinical probability of PE using the extended and simplified clinical model. The agreement between distinct observers was expressed by a weighted kappa (j). A weighted j value of 1 corresponds to perfect agreement, 0 to agreement as expected by chance. We also calculated a weighted j for the agreement between the results of the extended clinical model and the clinical probability estimate.In a total of 45 consecutive patients independent, duplicate assessments of the clinical pretest probability of PE using the clinical model were available for analyses. Of the 45 patients, 13 h...

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The exercise electrocardiogram: Differences in interpretation

Cited by 69 publications

References 4 publications

A high-pass phaseless filter for eliminating low-frequency ECG noise during exercise and its clinical application to automatic analysis of the heart rate and ST segment level.

A high-pass phaseless filter for eliminating low-frequency ECG noise during exercise and its clinical application to automatic analysis of the heart rate and ST segment level.

On-line processing of orthogonal exercise electrocardiograms

Observer variability in the assessment of clinical probability in patients with suspected pulmonary embolism

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