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Diagnostic and Prognostic Value of Exercise Electrocardiographic Test Variables in Coronary Artery Disease
KTH, School of Technology and Health (STH), Medical Engineering.
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The diagnostic performance of conventional analysis of the exercise electrocardiographic (ECG) test for the detection of coronary artery disease (CAD) is limited to 70-75%. The exercise ECG test is the most widely used non-invasive method for assessing CAD and even a small improvement in the diagnostic performance is important. The objective of this thesis was to investigate the diagnostic performance of the exercise ECG test for diagnosis of CAD and the prognostic performance of the test for predicting acute myocardial infarction (AMI), in both men and women.

In the diagnostic part of the present study, aimed at finding the optimal diagnostic information during the exercise and recovery phase, 1,877 electrocardiograms selected from 8,322 consecutive patients undergoing a routine exercise test on bicycle ergometer were evaluated. CAD was verified angiographically in 669 patients and excluded in 1,208 patients, by angiography (119 patients), by myocardial scintigraphy (250 patients), or on clinical grounds (839 patients).

The diagnostic performance of ST-segment amplitude, and the difference between heart rate (HR) matched recovery and exercise ST-segment amplitudes (ST/HR difference), were evaluated by constructing receiver operating characteristic (ROC) curves for each sample point every 12th second during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST/HR difference. Both methods performed better in men than in women and the diagnostic information appeared mainly in leads I, -aVR, II, V4, V5 and V6.

The effect of different sampling rates (1, 2 and 5 samples/min) on the CAD discrimination ability of ST/HR loop area was evaluated by using ROC curves. A use of sampling frequency below 2 samples/min resulted in a significantly diminished diagnostic performance.

ST-segment and ST/HR variables were compared during exercise and during early post-exercise recovery in terms of diagnostic discrimination capacity and optimal partition values. Discriminating capacity of the methods was evaluated by the use of ROC areas. Partition values, providing the combination of the best sensitivity and specificity, were established. The results demonstrate that analysis of post-exercise ST/HR hysteresis offers the most accurate and gender indifferent identification of patients with CAD.

The prognostic part of the study included 8,317 of the 8,322 patients and covered a mean follow-up period of 9.5 years. This part of the study was used to evaluate the long-term prognostic value of ST/HR hysteresis in predicting AMI and all-cause mortality in men and women. ST/HR hysteresis appears to improve the prognostic ability of an exercise ECG test for AMI and all-cause mortality in a long term perspective compared to conventional ST-segment and ST/HR indicators in both genders and clearly more markedly in women.

Place, publisher, year, edition, pages
Stockholm: KTH , 2009. , 65 p.
Series
Trita-STH : report, ISSN 1653-3836 ; 2009:3
Keyword [en]
exercise ECG test, coronary artery disease, acute myocardial infarction
National Category
Medical Laboratory and Measurements Technologies
Identifiers
URN: urn:nbn:se:kth:diva-11289ISBN: 978-91-7415-457-3 (print)OAI: oai:DiVA.org:kth-11289DiVA: diva2:272144
Public defence
2009-11-06, Sal 4-221, Alfred Nobels Allé 12, Huddinge, 09:00 (English)
Opponent
Supervisors
Note
QC 20100726Available from: 2009-10-14 Created: 2009-10-14 Last updated: 2010-07-26Bibliographically approved
List of papers
1. Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase
Open this publication in new window or tab >>Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase
2005 (English)In: Journal of Electrocardiology, ISSN 0022-0736, E-ISSN 1532-8430, Vol. 38, no 2, 130-138 p.Article in journal (Refereed) Published
Abstract [en]

The temporal distribution of the diagnostic information for the detection of coronary artery disease (CAD) provided by exercise-induced electrocardiographic (ECG) ST-segment amplitude changes in different ECG leads in men and women has not been fully investigated. To shed further light in this area, 1877 electrocardiograms selected from 8322 patients undergoing a routine exercise test on a bicycle ergometer were evaluated. ST-segment amplitude and the difference between heart rate-matched recovery and exercise ST-segment amplitudes (ST/HR difference) were measured. Coronary artery disease was verified angiographically in 669 patients and excluded in 1208 patients by angiography (n = 119), by myocardial scintigraphy (n = 250), or on clinical grounds (n = 839). The diagnostic performance of the 2 ECG methods used was assessed by constructing receiver operating characteristic curves for each sampling point every 12 seconds during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST-amplitude hysteresis assessed by the difference between recovery ST-segment amplitude and exercise ST-segment amplitude at matched heart rate. Both methods performed better in men and the diagnostic information appeared mainly in leads I, -aVR, II, V-4, V-5, and V-6. The best discrimination of CAD is provided by analysis of ST-segment amplitude changes in 6 specific leads early during the recovery phase. This information should be targeted by exercise ECG diagnostic methods.

Keyword
exercise ECG test, computer analysis, ST depression, ST/HR analysis, myocardial ischemia, coronary artery disease
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-11331 (URN)10.1016/j.jelectrocard.2004.10.008 (DOI)000229256900010 ()
Note
QC 20100726Available from: 2009-10-27 Created: 2009-10-27 Last updated: 2012-03-23Bibliographically approved
2. Exercise electrocardiography for diagnosis of coronary artery disease: impact of sampling rate on the diagnostic performance of ST/HR-loop based on data from early recovery phase
Open this publication in new window or tab >>Exercise electrocardiography for diagnosis of coronary artery disease: impact of sampling rate on the diagnostic performance of ST/HR-loop based on data from early recovery phase
2007 (English)In: Clinical Physiology and Functionel Imaging, ISSN 1475-0961, Vol. 28, no 2, 96-100 p.Article in journal (Refereed) Published
Abstract [en]

Quantitative analysis of electrocardiographic ST-segment/heart rate relationship (ST/HR loop) during early recovery phase of exercise stress test provides a sensitive tool for the detection of coronary artery disease (CAD). This study evaluates the effect of data sampling frequency on the diagnostic performance of ST/HR loop in 1876 patients undergoing a routine exercise test on a bicycle ergometer. CAD was verified angiographically in 668 patients and excluded by coronary angiography (n = 119), myocardial scintigraphy (n = 250) and on clinical grounds (n = 839) in 1208 patients. The normalized ST/HR loop area was calculated in all cases by integration of ST-segment amplitude difference from the end of exercise to the end of the first 3 min of recovery period over HR and dividing the integral by the HR difference over the integration period. The effect of different sampling rates (one, two and five samples per minute) on the CAD discrimination ability of ST/HR loop area was subsequently evaluated using receiver operating characteristic (ROC) curves. Reduction in ST/HR data sampling frequency from two to one sample per minute resulted in a significantly decreased diagnostic performance of the ST/HR loop whereas no differences in CAD discrimination capacity were observed between sampling frequencies of two and five samples per minute. The choice of ST/HR data sampling frequency may have a significant impact on the CAD diagnostic ability of the ST/HR loop. The use of sampling frequency below two samples per minute results in a significantly diminished diagnostic performance, a fact that should be taken into consideration when employing ST/HR diagnostic procedures.

Keyword
exercise stress test; ischaemic heart disease; rate recovery loop; sampling frequency; ST-segment depression
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-11332 (URN)10.1111/j.1475-097X.2007.00780.x (DOI)000252897100005 ()2-s2.0-39149098147 (Scopus ID)
Note
QC 20100726Available from: 2009-10-27 Created: 2009-10-27 Last updated: 2010-12-06Bibliographically approved
3. Diagnostic performance and partition values of exercise electrocardiographic variables in the detection of coronary artery disease - improved accuracy by using ST/HR hysteresis
Open this publication in new window or tab >>Diagnostic performance and partition values of exercise electrocardiographic variables in the detection of coronary artery disease - improved accuracy by using ST/HR hysteresis
Show others...
2010 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 30, no 2, 98-106 p.Article in journal (Refereed) Published
Abstract [en]

P>Exercise electrocardiography is widely used for initial identification of patients with coronary artery disease (CAD). This study compares the measurements of ST-segment changes during exercise and during early postexercise recovery in terms of diagnostic discrimination capacity and optimal partition values. Data from 1876 patients undergoing a routine bicycle exercise test were analysed. CAD was angiographically verified in 668 patients, and excluded by angiography (n = 119), myocardial scintigraphy (n = 250), and on clinical grounds (n = 839) in 1208 patients. Postexercise ST/HR hysteresis was calculated as normalized for heart rate (HR) ST/HR loop area during the first 3 min of recovery. ST/HR index was obtained by dividing the overall ST amplitude change during exercise by exercise-induced HR change, and ST/HR slope was calculated using linear regression analysis of ST/HR data pairs during exercise. ST-segment depression was measured during, and for 3 min after the exercise. Discriminating capacity of the methods was evaluated in terms of receiver operating characteristic areas and optimal partition values providing the combination of the best sensitivity and specificity were established. The best diagnostic discrimination was provided by ST/HR hysteresis at optimal partition value of -15 mu V, followed by postexercise ST amplitude measurements at gender-specific partition values of -10 to -90 mu V, ST/HR slope [partition value 2 center dot 4 mu V (beats/min)-1], ST/HR index [partition value 1 center dot 6 mu V (beats/min)-1], and ST-segment depression during exercise (partition value 70 mu V in men and 90 mu V in women). The results demonstrate that analysis of postexercise ST/HR hysteresis offers the most accurate and gender indifferent identification of patients with CAD.

Keyword
exercise test, ischemic heart disease, ST, HR hysteresis, HR index, HR slope, ST-segment depression
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-14210 (URN)10.1111/j.1475-097X.2009.00909.x (DOI)000274438800003 ()2-s2.0-76949103976 (Scopus ID)
Note
QC 20110126Available from: 2010-07-26 Created: 2010-07-26 Last updated: 2011-01-26Bibliographically approved
4. Analysis of ST/HR hysterisis improves long-term prognostic value of exercise ECG test.
Open this publication in new window or tab >>Analysis of ST/HR hysterisis improves long-term prognostic value of exercise ECG test.
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-14209 (URN)
Note

QC 20100726

Available from: 2010-07-26 Created: 2010-07-26 Last updated: 2016-03-16Bibliographically approved

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