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Comparison of five methods for the measurement of left ventricular ejection time
492
BRIEF REPORTS
Comparisonof Five Methods for the Measurement of left Ventricular Ejection Time CATHERINE C. AVGEROPOULOU, MD PETER S. RAHKO, MD
1
eft ventricular ejection time (ET] is a parameter frequently used in the noninvasive evaluation of systolic functi0n.l This parameter is usually obtained from the carotid pulse. The capability for recording the carotid pulse, however, is not readily available in all echocardiographic systems. Thus, alternative methods such as the M-mode tracing of the aortic valve or Doppler echocardiographic recordings of aortic flow have been substituted for the carotid pulse.2-4 Little information currently exists as to whether these alternative methods give equivalent measurements of ET. The present study compared ET measured by the carotid pulse to 4 alternative methods and evaluated intra-and interobserver variability of each of these methods.
From the Section of Cardiology, Department of Medicine, University of Wisconsin Medical School, Madison, Wisconsin. Manuscript received July 4, 1987; revised manuscript received and accepted September 21,1987.
The study was prospective and comprised 34 subjects (23 men and 11 women) with a mean age of 38 years [range 16 to 741, present for routine clinical echocardiographic studies. Only patients with highquality pulse tracings, aortic valve echocardiograms and aortic Doppler recordings were studied. The echocardiograms were obtained on a HewJett-Packard 7702OC phased array system. All tracings were obtained at 300 mm/s using standard techniques. A minimum of 3 to 5 complexes were measured and the results averaged. The ET was measured using 5 techniques: from the carotid pulse at the first onset of the most rapid upstroke to the incisural (Figure I); from the aortic valve M-mode from leaflet opening to coaptation (Figure 2); from the pulsed Doppler tracing from leading edge to leading edge of the spectral envelope (pulsed Doppler I) and from midpoint to midpoint of valve closure artifacts (pulsed Doppler II, Figure 3). The latter method was also applied to the measurement of the continuous-wave Doppler signal from the aortic valve (Figure 4). Two observers measured each study twice, blind to each other’s results, in 2 sessions, 2 weeks apart. Intraobserver variation was calculated for each observer as a percentage, using the following formula: (Xl - X2)/[(Xl + X2] X 0.51 X 100 where X1 = first observation, Xz = second observation2 Interobserver variation was calculated in a similar manner using the results of the second reading session for each observer. The results were ana-
._
- ^^_ -. “_-‘-)
^. -
. e-_.”
I
.I
FIGURE 1. Carotid pulse recording shows wlth arrows the ejeciion time interval. Time scale is indicated at the top and is similar for all figures.
FIGURE 2. M-mode of the aortic valve showing used for ejection time.
interval
(arrows)
February 15, 1988
TABLE I
Mean Values for Ejection Time and lntraobserver Observer
TABLE II
Carotid pulse Aortic valve Pulsed Doppler I Pulsed Doppler II CW Doppler
315 320 300 295 293
CW = continuous
wave.
Interobserver
Carotid pulse Aortic valve Pulsed Doppler I Pulsed Doppler II CW Doppler CW = continuous
33 38 35 33 36
309 313 290 290 290
f f f f f
31 40 32 31 38
Observer
Difference 2.5 3.0 4.1 2.7 2.8
2.3 3.6 3.6 2.8 2.2
f f f f f
(%) 2.6 3.1 3.6 2.8 2.7
OF CARDIOLOGY
Volume 61
f f f f f
(%) 2.1 3.3 3.2 2.8 2.4
493
Session 1 313 313 287 290 290
f f f f f
29 33 32 32 38
Session 2 310 311 285 290 289
f f f f f
29 32 33 33 37
B
Difference 0.9 0.9 0.9 0.7 0.8
f f f f f
(%) 1.2 1.3 1.7 1.2 1.3
TABLE III Comparison of Ejection Time Measured Pulse Versus Other Methods
Variability Difference
Parameter
f f f f f
JOURNAL
Variability
A
Session 2
Session 1
Parameter
THE AMERICAN
by Carotid
r Value 0.94 0.93 0.92 0.93 0.97
wave.
Parameter Carotid pulse Aoritc valve Pulsed Doppler I Pulsed Doppler II CW Doppler p Value * Significantly
Mean Values
r Value vs Carotid
Difference vs Carotid (%)
310 f 30’ 313 f 36’ 289 f 32 290 f 31 289 f 38 0.0015
0.90 0.74 0.76 0.83 .
3.3.f.3.9’ 7.4 f 7.3 7.9 f 7.7 8.0 f 7.8 0.025
different from other values by multiple range testing.
FIGURE 3. Pulsed Doppler tracing shows 2 slightly different methods of measuring ejection time. On the left, the arrows indicate leading edge to leading edge of the spectral envelope (pulsed Doppler I). On the right, the arrows indicate a midpoint to mldpolnt measurement using the valve closure artifact (pulsed Doppler II).
Jyzed using l-way analysis of variance, protected least squares difference multiple range testing5 and linear regression analysis. Mean values for ET as well as intraobserver variability for all measurement sessions are listed in Table 1. There was good agreement between sessions for both observers and no significant difference in intraobserver variability between any of the measurements. Interobserver variability is listed in Table II. There was excellent agreement between the 2 observers and no significant difference in interobserver variability among the 5 different techniques.
Table III illustrates the ET obtained by taking the average values of the second session for both observers. There was a significant difference ( p = 0.0015) between the values, with all 3 Doppler measurements being shorter than the ET determined by carotid pulse or aortic valve M-mode. Likewise, there was a lower correlation and higher percentage difference between Doppler-derived ET and the carotid pulse than with the aortic valve M-mode and carotid pulse. This study has shown that all 5 techniques for measuring ET are equally reproducible. In agreement with
494
BRIEF REPORTS
Previous studies have also found no difference in ET between the carotid pulse and aortic valve M-mode,3 and between the carotid pulse and micromanometerderived central aortic pressuree6It is possible that flow velocity, as measured by Doppler, is a slightly shorter event than mechanical movements of the carotid artery or aortic valve. Thus, a Doppler ET is not necessarily interchangeable with a non-Doppler ET. Laboratories using Doppler to measure ET should consider adjusting their normal ranges for measurement of ventricular performance that include ET. Acknowledgment: We are grateful to Jean Hansen for excellent assistance in the preparation of this manuscript.
FIGURE 4. Continuous-wave Doppler tracing. The arrows indicate the interval from valve motion artifacts. These motion artifacts were usually very distinct and closely correlated with onset and conclusion of aortic flow.
previous work,1*2 inter- and intraobserver variability was acceptably small. However, there was a small but systematic underestimation of ET by all the Doppler methods but not by the aortic valve M-mode method.
A XII Century Description of Congestive Heart Failure JON E. LUTZ, MD
0
ne does not need to be a physician to be an accurate observer. I have found what is most certainly a description of congestive heart failure in a biography of the Byzantine emperor Alexius I Comnenus, who was born in 1056 and reigned from 1081 to 1118, written by his daughter Anna. A Medline search of the medical literature in the English language failed to contain references to this or earlier descriptions of congestive heart failure. This biography was first translated from Greek into English in 1928, an,d the translation into contemporary English by the well-known Byzantine historian E.R.A. Sewter was published in 1969.l Alexius reorganized the Byzantine Empire and regained lost territory. It was his request for mercenaries to fight the Turks that led to the organization of the First Crusade.2 Before his final, fatal illness at age 62, he was in good health and athletic, save for suffering from attacks of gout in his later years.1 From the U.S. Naval Hospital, FPO New York, New York 09571. Manuscript received July 27,1987; revised manuscript received September 22.1987, and accepted September 23. The views expressed herein are those of the author and do not reflect those of the Department of Defense or the Department of the Navy.
1. Lewis RP, Rittger SE, Forester WF. Boudoulas H. A critical review of the systolic time intervals. Circulation 1977:56:146-158. 2. Gardin JM. Dabestani A, Matin K, Allfie A, Russell D, Henry W. Reproducibility of Doppler oortic blood flow measurements: studies on intraobserver, interobserver and day-to-day variability in normal subjects. Am J Cordiol 1984;54:1092-1098. 3. Maron BJ. Gottdiener JS, Arce J, Rossing DR. Wesley YE, Epstein SE. Dynamic subaortic obstruction in hypertrophic cardiomyopathy: analysis by pulsed Doppler echocardiography. JACC 1985;6:1-15. 4. Cogswell TL, Sagar KB, Wann LS. Left ventricular ejection dynamics in hypertrophic cardiomyopathy and aortic stenosis: comparison with the use of Doppler echocardiography. Am Heart J 1987;113:llo-li6. 5. Snedecor GW, Cochran WG. Statistical Methods. 7th ed. Ames, lowo: Iowa State University Press, 1980;233-237. 6. Martin CE, Shaver JA. Thompson NE, Reddy PS. Leonard JJ.Direct correlotion of external systolic time intervals with internal indices of left ventricular function in man. Circulation 1971;44:419-431.
It is important to recall that the achievements of antiquity, including those of medicine, were transmitted to western Europe largely through the Arabs and the Greeks2 Greek and Roman culture existed unbroken through the centuries in the Byzantine Empire. Galen, a Greek court physician to several Roman emperors in the second century A.D., was considered the ultimate medical authority in medieval Europe.3 Presumably, Byzantine physicians continued the Galenic tradition. The Arabs, whose states for centuries bordered the Empire, made further contributions to medicine. Most noted was Avicenna (980 to 10371, court physician at Baghdad. Familiar with classical Greek literature and second only to Galen in terms of influencing medieval medicine,3 it is quite possible that his works were known to the Byzantine physicians in Alexius’ day. And what was the state of the art in the understanding of edema? A later English physician, John of Gaddesden, quoted Avicenna as stating that, “Hydrops is an error of the combining forces in the whole body, following on a change in the digestive energy in the liver.‘13 Citing Avicenna and the earlier physician Constantine, he described the several methods of treatment of hydrops: by diuretic medicines, sweating, emetics and purgatives, by having the patient drink his own urine and, amazingly, by paracentesis, which was recommended only for strong patients. This could be done several times3 The upper classes in Byzantium, unlike those in western Europe, were literate.2 Hence, perhaps, Anna’s ability to serve as an arbiter at the conference of physicians attending her father. Selected passages of
BRIEF REPORTS
Comparisonof Five Methods for the Measurement of left Ventricular Ejection Time CATHERINE C. AVGEROPOULOU, MD PETER S. RAHKO, MD
1
eft ventricular ejection time (ET] is a parameter frequently used in the noninvasive evaluation of systolic functi0n.l This parameter is usually obtained from the carotid pulse. The capability for recording the carotid pulse, however, is not readily available in all echocardiographic systems. Thus, alternative methods such as the M-mode tracing of the aortic valve or Doppler echocardiographic recordings of aortic flow have been substituted for the carotid pulse.2-4 Little information currently exists as to whether these alternative methods give equivalent measurements of ET. The present study compared ET measured by the carotid pulse to 4 alternative methods and evaluated intra-and interobserver variability of each of these methods.
From the Section of Cardiology, Department of Medicine, University of Wisconsin Medical School, Madison, Wisconsin. Manuscript received July 4, 1987; revised manuscript received and accepted September 21,1987.
The study was prospective and comprised 34 subjects (23 men and 11 women) with a mean age of 38 years [range 16 to 741, present for routine clinical echocardiographic studies. Only patients with highquality pulse tracings, aortic valve echocardiograms and aortic Doppler recordings were studied. The echocardiograms were obtained on a HewJett-Packard 7702OC phased array system. All tracings were obtained at 300 mm/s using standard techniques. A minimum of 3 to 5 complexes were measured and the results averaged. The ET was measured using 5 techniques: from the carotid pulse at the first onset of the most rapid upstroke to the incisural (Figure I); from the aortic valve M-mode from leaflet opening to coaptation (Figure 2); from the pulsed Doppler tracing from leading edge to leading edge of the spectral envelope (pulsed Doppler I) and from midpoint to midpoint of valve closure artifacts (pulsed Doppler II, Figure 3). The latter method was also applied to the measurement of the continuous-wave Doppler signal from the aortic valve (Figure 4). Two observers measured each study twice, blind to each other’s results, in 2 sessions, 2 weeks apart. Intraobserver variation was calculated for each observer as a percentage, using the following formula: (Xl - X2)/[(Xl + X2] X 0.51 X 100 where X1 = first observation, Xz = second observation2 Interobserver variation was calculated in a similar manner using the results of the second reading session for each observer. The results were ana-
._
- ^^_ -. “_-‘-)
^. -
. e-_.”
I
.I
FIGURE 1. Carotid pulse recording shows wlth arrows the ejeciion time interval. Time scale is indicated at the top and is similar for all figures.
FIGURE 2. M-mode of the aortic valve showing used for ejection time.
interval
(arrows)
February 15, 1988
TABLE I
Mean Values for Ejection Time and lntraobserver Observer
TABLE II
Carotid pulse Aortic valve Pulsed Doppler I Pulsed Doppler II CW Doppler
315 320 300 295 293
CW = continuous
wave.
Interobserver
Carotid pulse Aortic valve Pulsed Doppler I Pulsed Doppler II CW Doppler CW = continuous
33 38 35 33 36
309 313 290 290 290
f f f f f
31 40 32 31 38
Observer
Difference 2.5 3.0 4.1 2.7 2.8
2.3 3.6 3.6 2.8 2.2
f f f f f
(%) 2.6 3.1 3.6 2.8 2.7
OF CARDIOLOGY
Volume 61
f f f f f
(%) 2.1 3.3 3.2 2.8 2.4
493
Session 1 313 313 287 290 290
f f f f f
29 33 32 32 38
Session 2 310 311 285 290 289
f f f f f
29 32 33 33 37
B
Difference 0.9 0.9 0.9 0.7 0.8
f f f f f
(%) 1.2 1.3 1.7 1.2 1.3
TABLE III Comparison of Ejection Time Measured Pulse Versus Other Methods
Variability Difference
Parameter
f f f f f
JOURNAL
Variability
A
Session 2
Session 1
Parameter
THE AMERICAN
by Carotid
r Value 0.94 0.93 0.92 0.93 0.97
wave.
Parameter Carotid pulse Aoritc valve Pulsed Doppler I Pulsed Doppler II CW Doppler p Value * Significantly
Mean Values
r Value vs Carotid
Difference vs Carotid (%)
310 f 30’ 313 f 36’ 289 f 32 290 f 31 289 f 38 0.0015
0.90 0.74 0.76 0.83 .
3.3.f.3.9’ 7.4 f 7.3 7.9 f 7.7 8.0 f 7.8 0.025
different from other values by multiple range testing.
FIGURE 3. Pulsed Doppler tracing shows 2 slightly different methods of measuring ejection time. On the left, the arrows indicate leading edge to leading edge of the spectral envelope (pulsed Doppler I). On the right, the arrows indicate a midpoint to mldpolnt measurement using the valve closure artifact (pulsed Doppler II).
Jyzed using l-way analysis of variance, protected least squares difference multiple range testing5 and linear regression analysis. Mean values for ET as well as intraobserver variability for all measurement sessions are listed in Table 1. There was good agreement between sessions for both observers and no significant difference in intraobserver variability between any of the measurements. Interobserver variability is listed in Table II. There was excellent agreement between the 2 observers and no significant difference in interobserver variability among the 5 different techniques.
Table III illustrates the ET obtained by taking the average values of the second session for both observers. There was a significant difference ( p = 0.0015) between the values, with all 3 Doppler measurements being shorter than the ET determined by carotid pulse or aortic valve M-mode. Likewise, there was a lower correlation and higher percentage difference between Doppler-derived ET and the carotid pulse than with the aortic valve M-mode and carotid pulse. This study has shown that all 5 techniques for measuring ET are equally reproducible. In agreement with
494
BRIEF REPORTS
Previous studies have also found no difference in ET between the carotid pulse and aortic valve M-mode,3 and between the carotid pulse and micromanometerderived central aortic pressuree6It is possible that flow velocity, as measured by Doppler, is a slightly shorter event than mechanical movements of the carotid artery or aortic valve. Thus, a Doppler ET is not necessarily interchangeable with a non-Doppler ET. Laboratories using Doppler to measure ET should consider adjusting their normal ranges for measurement of ventricular performance that include ET. Acknowledgment: We are grateful to Jean Hansen for excellent assistance in the preparation of this manuscript.
FIGURE 4. Continuous-wave Doppler tracing. The arrows indicate the interval from valve motion artifacts. These motion artifacts were usually very distinct and closely correlated with onset and conclusion of aortic flow.
previous work,1*2 inter- and intraobserver variability was acceptably small. However, there was a small but systematic underestimation of ET by all the Doppler methods but not by the aortic valve M-mode method.
A XII Century Description of Congestive Heart Failure JON E. LUTZ, MD
0
ne does not need to be a physician to be an accurate observer. I have found what is most certainly a description of congestive heart failure in a biography of the Byzantine emperor Alexius I Comnenus, who was born in 1056 and reigned from 1081 to 1118, written by his daughter Anna. A Medline search of the medical literature in the English language failed to contain references to this or earlier descriptions of congestive heart failure. This biography was first translated from Greek into English in 1928, an,d the translation into contemporary English by the well-known Byzantine historian E.R.A. Sewter was published in 1969.l Alexius reorganized the Byzantine Empire and regained lost territory. It was his request for mercenaries to fight the Turks that led to the organization of the First Crusade.2 Before his final, fatal illness at age 62, he was in good health and athletic, save for suffering from attacks of gout in his later years.1 From the U.S. Naval Hospital, FPO New York, New York 09571. Manuscript received July 27,1987; revised manuscript received September 22.1987, and accepted September 23. The views expressed herein are those of the author and do not reflect those of the Department of Defense or the Department of the Navy.
1. Lewis RP, Rittger SE, Forester WF. Boudoulas H. A critical review of the systolic time intervals. Circulation 1977:56:146-158. 2. Gardin JM. Dabestani A, Matin K, Allfie A, Russell D, Henry W. Reproducibility of Doppler oortic blood flow measurements: studies on intraobserver, interobserver and day-to-day variability in normal subjects. Am J Cordiol 1984;54:1092-1098. 3. Maron BJ. Gottdiener JS, Arce J, Rossing DR. Wesley YE, Epstein SE. Dynamic subaortic obstruction in hypertrophic cardiomyopathy: analysis by pulsed Doppler echocardiography. JACC 1985;6:1-15. 4. Cogswell TL, Sagar KB, Wann LS. Left ventricular ejection dynamics in hypertrophic cardiomyopathy and aortic stenosis: comparison with the use of Doppler echocardiography. Am Heart J 1987;113:llo-li6. 5. Snedecor GW, Cochran WG. Statistical Methods. 7th ed. Ames, lowo: Iowa State University Press, 1980;233-237. 6. Martin CE, Shaver JA. Thompson NE, Reddy PS. Leonard JJ.Direct correlotion of external systolic time intervals with internal indices of left ventricular function in man. Circulation 1971;44:419-431.
It is important to recall that the achievements of antiquity, including those of medicine, were transmitted to western Europe largely through the Arabs and the Greeks2 Greek and Roman culture existed unbroken through the centuries in the Byzantine Empire. Galen, a Greek court physician to several Roman emperors in the second century A.D., was considered the ultimate medical authority in medieval Europe.3 Presumably, Byzantine physicians continued the Galenic tradition. The Arabs, whose states for centuries bordered the Empire, made further contributions to medicine. Most noted was Avicenna (980 to 10371, court physician at Baghdad. Familiar with classical Greek literature and second only to Galen in terms of influencing medieval medicine,3 it is quite possible that his works were known to the Byzantine physicians in Alexius’ day. And what was the state of the art in the understanding of edema? A later English physician, John of Gaddesden, quoted Avicenna as stating that, “Hydrops is an error of the combining forces in the whole body, following on a change in the digestive energy in the liver.‘13 Citing Avicenna and the earlier physician Constantine, he described the several methods of treatment of hydrops: by diuretic medicines, sweating, emetics and purgatives, by having the patient drink his own urine and, amazingly, by paracentesis, which was recommended only for strong patients. This could be done several times3 The upper classes in Byzantium, unlike those in western Europe, were literate.2 Hence, perhaps, Anna’s ability to serve as an arbiter at the conference of physicians attending her father. Selected passages of