Measurement of Right and Left Ventricular Systolic

Time Intervals by Echocardiography By STEPHEN HIRSCHFELD, M. D., RICHARD MEYER, M. D., DAVID C. SCHWARTZ, M.D., JOAN KORFHAGEN, U.T.,

AND

SAMUEL KAPLAN, M.D.

SUMMARY One of the noninvasive methods of evaluating left ventricular performance is the measurement of left ventricular systolic time intervals (LVSTI). However, noninvasive measurement of right ventricular systole by this technique has been unreliable because of the inability to accurately time the onset of right ventricular ejection. Excellent correlation of LVSTI measured from the carotid pulse and those determined from the echocardiogram was demonstrated in 15 patients. STI of the right ventricle (RVSTI) were measured in a similar fashion from the pulmonary valve echo in 11 normal children. Right ventricular ejection time (RVET) was longer than left ventricular ejection time (LVET). Right ventricular pre-ejection period (RPEP) was shorter than left ventricular pre-ejection period (LPEP). In 15 children with transposition of the great arteries (TGA) the situation was reversed. RVET was shortened and RPEP was prolonged as the right ventricle contracted against systemic resistance; whereas, the LVET lengthened and LPEP shortened with ejection into a low pressure pulmonary circuit. Our studies in a total of 41 patients indicate that accurate, noninvasive measurement of right, as well as left, ventricular STI can be obtained with the use of echocardiography.

Additional Indexing Words: Left pre-ejection period Right ventricular ejection time

Left ventricular ejection time Transposition of the great arteries

Right pre-ejection period

notch, and PEP is obtained indirectly by subtracting LVET from QS2. To date, noninvasive assessment of right ventricular performance by measurement of STI has not been possible because of the inability to define accurately the onset of right ventricular ejection. The purpose of this study was to demonstrate that right, as well as left, ventricular STI can be measured noninvasively by the use of ultrasound. In addition, patients with transposition of the great arteries (TGA) were studied because they have a unique reversal of systemic and pulmonic vascular circuits, which permitted evaluation of the effect of this reversal on RV and LVSTI.

NONINVASIVE TECHNIQUES have become established in the study of cardiovascular disease. With these methods valuable anatomic and physiologic data may be obtained without risk to the patient. Noninvasive evaluation of left ventricular performance has been possible by the measurement of left ventricular systolic time intervals (LVSTI).' These intervals are conveniently derived from the simultaneous high-speed recording of the electrocardiogram (ECG), the indirect carotid pulse tracing, and the phonocardiogram. Three LVSTI are conventionally measured:'`3 total electromechanical systole (QS2), the left ventricular ejection time (LVET), and the pre-ejection period (PEP). QS2 is defined from the onset of ventricular depolarization (Q wave of ECG) to the initial high frequency vibraton of the aortic component of the second heart sound. LVET is derived from the onset of the upstroke of the carotid pulse to the incisural

Methods The echocardiograms were obtained with a Hoffrel 101 ultrasonoscope. Simultaneous strip chart recordings of the echocardiogram, phonocardiogram, carotid pulse tracing and ECG were obtained with a Cambridge Multichannel Physiological Recorder, Amplifier Type 72352. The ECG lead which most clearly demonstrated early ventricular depolarization, usually the Q wave, was chosen for timing the onset of electrical systole. The phonocardiogram was recorded with a piezo-electric, high impedance microphone having a frequency band of 100 to 600 cycles per second. Recordings were made at the base of the heart in the higher frequency sound spectrum. The carotid pulse measuring equipment consisted of an electronic amplifier driven by a piezo-electric pulse transducer. The sensing device is a plastic cone connected

From Department of Pediatrics, College of Medicine, University of Cincinnati, Children's Hospital, Cincinnati, Ohio. Supported by NIH Grant #l5T01 HL 05728 and the American Heart Association, Southwestern Ohio Chapter. Address for reprints: Stephen Hirschfeld, M.D., Division of Cardiology, Children's Hospital, Cincinnati, Ohio 45229. Received June 19, 1974; revision accepted for publication October 10, 1974. 304

Circulation, Volume 51, February 1975

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SYSTOLIC TIME INTERVALS/ECHOCARDIOGRAFPLY bV polvethvlene tubing to the crystal enclosed in a molded cvlindrical bodv. The transducer's time constant is greater than 1.6 seconds. The system is air-filled and permits recording of an arterial pulse of sufficiently large, amplitude to clearly define its onset and the incisural notch. A 2.25 MHz, ]/4 inch outside diameter transducer, focused at 5 cm, was tused to obtain the echocardiograms. The aortic valve echoes were recorded from the third or fourth intercostal space at the left sternal border, in the manner previoLsly described by Gramiak and Shah.4 After recording the mitral valve, the transducer beam was directed medially and suiperiorly to locate the aortic cusps. The pulmonic valve was recorded from the second or third intercostal space vith the sonar beam aimed laterally and superiorly,' In infants the pullmonary artery was located by rotating the tranisduicer laterallv from the aorta to the pulmonary arterv \vithouit moving the trainsducer. If the great arteries xere tranispose(l, the aortic cusps were recorded at the left sternal border in the fourth intercostal space with the transducer directed posteriorly and superiorly. The pulmonary artery was recorded at the midelavicular line in the third or fourth intercostal space, scanrning menially and sLuperiorly. The aortic valve echo had a chlaracteristic box-like configuiration, which permitted precise recognition of cusp opening anid closure (fig. 1). The rapid departure of the fine culsp echioes from the thick, closed valve echoes marked the onset of ejection. TFhe merging of the leaflets intto a thick valve echo inclicated the terminiation of ejection. The PEP xxas the interval from the Q wave of the ECGG to aortic valve

,3()5

operning. 'Total electromechanical systole meastured from the echocardiogram (Q A) was the sum of pre-ejection and ejectionl time.

RVSTI were measured uising the pulmonary valve ech)o in a manner simila. to the aortic valve echo. The timing of the onset arid termination of right ventricular ejection was facilitatedi whern the anterior and posterior pulmonic ctusps couLld be recorded simultaneously (fig. 2). However, when only the posterior puilmonic cusp could be recorded, the onset of ejectioni was chosen as the point of rapid posterior leaflet motion at which the closed-valve echo changed from a thick line to a very fine one (fig. 3). The terminationr of ejection was determined by the junction of the fine leaflet echo with the thick closed-valve echo following rapid arnterior motion. RPEP vas measured directly from the Q xx ave of the ECGG to the onset of pulmonic valve opening. Right ventricuilar electromechanical svstole (QP) was the sum of IPEP and RVET. Validation for this method of measuring RVSTI was accomplished by obtaining simultaneous pulmonary arterial pressuire tracings and pulmnonary valve echoes in patients xvith a varietv of congenital heart diseases (fig. 4). The pulmonary artery pressuire tracitng vas obtained with a 5 French Swan-Ganz flow-directed infant angiography

x~A t

**""

xi

N

it ;

Figure 1

Becor(ing of tlu ecliocardiogram., p/ionocardiogram (p)IonIO) electrocardiograi (ECG), anid carotid oilse illustrates the ST1 (d(erc(c/lfromi echlo anid carotid poilse tracing at a paper speed of 12.5 xc 4)5. c lectromiec/ianical .systole hbj echo Q)S 1ti c. clc=

(romcchliaiical sl;stole b)y/ carotid pulse tracing; I ET tricolar (ejecstion (iu PEP p ejec(ti period. (irculatnioni \Vl we 51. 1c 1rtiartuarl/ 195,

=

left cit?-

Figure 2 Rig/it ucn itrictd{ar 'TI are tricasored frormi a terior and postc rior plltmontic (u.s) cc/oes RPE1L = r/ght pm e-jection period; RET L =' rig/it cnetricular ejectiorn tirmc ; QP rig/it lec trotmiech/ianical st;.stole; J'. = pultoiary arteryl. Tinme lines, 40) =

sen1SC

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3()6

HIRSCHFELD FT AL.

RVET

QP--

PA PRESSURE

O

,1 tiR'W~tt

-

t --

P

E RVET

PA

P

RVET b5.;

O",joley'00#

£*

PA ECHO

1

SI

,, r.

I 'i

1.@

Figure 4 RIE (1

rig/i f

l (iltricil/ar Qsjtactiori

14olioZo1aryj arterial)

sioli/lltanrons ec/ho.Timalm fiisi 40 ris(c

timie

mcasured by

pr sisre mid

2 w as composed of 1 1 normal children, age 3 to 14 x1ho served as controls. PLulmonrarv and aortic valve echoes we re obtained in ordler to compare RN7 anid ILVSTI. Gr011p 3 consisted of 15 patients, age 2 weeks to 8 years, xv itt transposition of the great arteries in whomi b)oth RV and Grotip

Figure 3 e trir i/la r S T1 ais m ea.si redJfroiii t/i pos nrior 1)ii/tI o ti i (' usp BITP = rig/lit r (jr ctioni period. 1 1TT = rig/it u(e7 tric.,idlar (qje C5tionl time, )f' = rig/it elcketrooaie/liao7ic /l siystole; 1s = puls. 40 insec, a7ioiiirij arteir. 7Tim

Mig/itt

1'

i

ho( /*o.

years,

LXST1

Ivere determined (fig. 5). Foirteen patients had and tw o-w

an

iintact ventricular septum,

catheter,* XX hichi wXas connected to a P23db Statham straini Thle pressiure was recorded on a Cambridge gauge. NMiultichannel IPihYsiologic Recorder, which permitted simtiultaneous recording of the pulmonary artery pressure tracing and the pilmonary valve echo. RVfFT measured simultaneiously from the and

1)v echo differed

b)

pulmonarv less

than

5

arterial

msec

pressure

tracirng

in the nine patients

sttI(Iiecl (table 1). STI derived from

echocardiographic traciings wXere measured at 75 125 mm/see. At a paper speedl of 75 mmisee, it wX recogrnized that there was a potential error of 5-10 msec' which was judgecl insignificant. Time lines XXere recorded at 40 msec intervals. Measurements nXX-ere madie duiring the expiratorx phase of respiratiuin in older childrein. In infants with a rapid respiratory rate the shfrtest STI were selected to inirimize the influence of the respiratork variatioii. Fi ve separate complexes were mieasuired and averaged to obtain the final STI.

eek-old infant hiad the a small ventricular septal defect. Eleven children previouslv had undergone a Ml ustard procedurej and in this group the peak svstolic left ventricuilar pressure measuirecl less than 45 Ig. One patient who previously had undergone a oistardl proceclure had a left verntricular pressure of 60 mm f-ig, x-hich was approximately one-half of the systemic pressure.

Echogranms in the three remaining patients wvith

our mm /sec or

Table 1

as

Patients Fortx-one patients, age 2 weeks to 14 years, were evaluated. Group 1 consisted of 15 children with congenital heart disease whii were studied by simultarieouis echocardiogram, phonocardiogram, ancl carotid pulse tracing in order to compare the techniques for determining L7iSTI by echocardiograpliy and by carotid pulse tracing.

Comparison of RVET by Pulmonary Arterial Pressure Tracing and Echocardiogram RVET (msec) Patient

1

2 3 4 )

l

6 7 8 9

Age (yrs)

Diagnosis

Puilmonary pressure

Puilmonary valve echo

12

vs 1)

189

189

6/12 l1 12

vTsI)

229

233

AS !)

165

1 61;)

1

VS1)

188

5r

AS!)

27,3

276

243

243

3

vs J) AS41)

279

281

5

AS 1 )

268

265

12

ASI)

261

257

1

2 6/12

at rial septal defect; RVET Abbreviations: ASI) vent ricular septal ight vent ricular ejection tine; VSI) =

=

*itldxard

s

La)oratories, Sarnta An1iam California

defect. ('irculatiani

V

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a/aim

5,

Febriuary

1975.

SYSTOLIC TIME INTERVALS/ ECHOCARDIOGRAPHY

307

Table 2 Comparison of STI by Carotid Pulse Tracing and Echocardiogram*

TRANSPOSITION

1

2 3 4

Carotid

Age (yrs)

Patient

QS2

LVET

1/12

225

1 1/2

295

314 '313

3

4

7 8

8

9 10

11

323 272 361 333 264

1

264

11

12

342

12

13

32,'3 '342

4

6

13 14 157

8

14 14 14

230

Eclho LVE,T

PE1P

)

224

299)

148 207

78

9:3

1013

314

210

103

70 70 73 94

3J13

243

70

323 272

249

75 9()

361

342

264 240 182 181 238JS 242 242

1

200 211 24:3

QA

PEP

88

90 99

397

199 272 243 181 188 2 58 241 243 293

10

397

300

99

35 2

253

100f

:3311

254

100

3:,33

264 264

83

77 8582

342

'32:3

99

92

84

82 89 83 99

*Measurenent ini rnsee. Abbreviations: QS, electromechanical systole from carotid pulse tracinig; QA electromiechantical systole froin left ventricular ejectoln tlime; PETP echo; LVET preejection period.

-7~~~~~~~~~~

=

Group 2 (ftal)le 3)

LVET was shorter than RVET in all patients. The mean LVET/RVET ratio was 0.80 (range 0.75-0.89). However, LPEP was longer than RPEP in 9/10 patients (LPEP/RPEP ratio of 1.25 and range of 0.95 to 1.95) (fig. 6). These results are in accord with data obtained by invasive studies.7 9 .-:,.

9,0, ",A-

(;'roup.3 ita/le .)

m-.

In each patient with TGA the ratio of the LV to

Figure 5 T/he (e(lioe ardliogr.a

rof

a

patient

iitli

traii

p.sositioni

of

the great

syJstolic

tioe, intlternals dernted froni f/i ad aniterior aorti, ualve: LPEP= left pra-ejection period; I1ET teft tentriwular ijectioi fitrne; 1''I' = pulnionary arter,.; 1WE1.' riglit pre-ejection period,. 1VE1 = rig/if vteutri(,iilar ejection tinw. arterie.s dlemtionistr,ates p)osterior pmdnli7ionu,ii taltue die

Table 3 Right and Left Ventricular STI in Normal Children*

=

RVET

IVET IWVET

240

0.82

=

transposition were obtained prior to the operative repair. The peak left ventricular svstolic pressure in each measured less than 55 nim fig. No significant left ventricular outfloss gradie nt was measured in an> patient. None o}f the patienits in Group 3 had conduictiorn defects or congestive heart failure.

Results G(roiij)

1

ta/)le

2

The LVET measured simultaneously by carotid pulse tracing and echo differed by less than 3 msec in 10/15 patients and by less than 9 msec in the remaining five. The PEP varied by 5 msec or less in 14 of 15 patients and by 7 msev in one patient. C(i cn lation.

So

hr

Sex

Age (yrs)

LVET

312

19z)7

412 5)

241

F F F m F F F F F

11

181

12 113

2735

305 279 240 302

241

318

M M

14 14

300

373 319

8 8

8 %2

280 283 308

2:32 240 273 219

2354

0.86 0.82 0.78 0.89 0.78 0.75 (. 8 5 0.76 0.80 0.81

LPEP LPEP RPEP

52

76 62 92 8( 87 82 96 81 99

100

38

80) .58 63 70 5-9 66 82 56 80 51

RPEP

1.37 0. 95r) 1.07 1.42 1.14 1.47 1.24 1.17 1.45 1.24

1.95

*Measuremernts in msec. left ventricular ejection tirne; Abbreviatioins: LVET LPEP left pre-ejection period; l3 VET right ventriecular ejectioni time; RPEP right pre-ejectioii period. =

=

nanl

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HIRSCHFELD ET AL.

308

Figure 6 The average ratio of left-to-right ventricular STI in normal patients and patients with transposition of the great arteries.

RVSTI was reversed from that of normal subjects (fig. 6). The ratio of LVET to RVET averaged 1.22 (range 1.10 to 1.33). Similarly, the ratio of LPEP to RPEP was reversed and averaged 0.52 (range 0.38 to 0.69). Discussion

The accurate measurement of STI in infants has been limited because of the difficulty of obtaining reliable indirect arterial pulse tracings and high quality phonocardiograms. Previous studies in normal children have been confined to the measurement of LVSTI. 10-12

The echocardiogram provides

a

reliable and

sen-

sitive method of measuring left ventricular ejection. Data obtained from this study indicated that LVSTI derived from the aortic valve echo were reproducible

and demonstrated excellent correlation with simultaneous measurements from arterial pulse tracings. The echocardiogram offered the advantage that it could be performed on critically ill infants in whom the manipulation required to obtain arterial Table 4 Systolic Time Intervals in Transposition of the Great Arteries* Sex

M M M M M F M F M F M M M M M

Age (yrs)

LVET

1/12

198 208 230 239 274 243 200 306

2/12 1 2 2 2 3 3

3'2 4 4

4'2 4'2

295 280 313

5 2

243 293

7 7

313 317

RVET

148

LVET RVET

1.33 1.26 1.30 1.15 237 1.18 213 1.15 1.10 18a 260 1.18 230 1.26 234 1.20 248 1.27 1.24 196 238 1.23 265t) 1.18 265 1.20

165 178 207

LPEP RPEP

39 35 31 53 50 45 65

35 65 45 46 38 43 30 49

78 70 80 85 97 90 95 100 96 90 122 85 91 99 96

LPEP RPEP

0.50 0.50 0.38 0.65 0.51 0.50 0.68 0.55 0.69 0.50 0.38

0.45 0.47 0.50

0.51

*Measurement in msec. Abbreviations: LVET = left ventricular ejection time; LPEP = left pre-ejection period; RVET = right ventricular ejection time; RPEP = right pre-ejectiori period.

pulse recordings and phonocardiograms was contraindicated. The aortic valve echo permitted direct measurement of the LVSTI and obviated the need to record peripheral arterial pulses. The LVSTI have been of great clinical value because they afford a rapid noninvasive method of quantitating LV performance.`3 Myocardial failure produces a characteristic lengthening of PEP and shortening of LVET, while QS2 remains unaltered. The ratio of PEP to LVET has become a popular expression of LV performance and has been closely correlated with other measures of LV performance. Studies in adults with aortic stenosis have demonstrated prolongation of LVET and shortening of PEP which has permitted an estimation of the severity of obstruction.1 2 Drugs such as digitalis and catecholamines have a predictable influence on STI.1, 2 The ability to easily measure LVSTI by echo promises to extend their usefulness in infants and children. A noninvasive method for measuring RVSTI has not been described previously. The pulmonary valve echo offers a reliable means of timing the events of right ventricular systole. Although the recording of the pulmonary valve echoes has been technically more difficult than the aortic, in our laboratory it has been possible to record the opening and closure of pulmonary valve cusps in 70-80% of infants and 50-60% of older children. As demonstrated by this study, the variation of RVSTI from cardiac cycle to cardiac cycle was less than 5 msec, when measured in expiration at comparable heart rates. The effects of the natural reversal of systemic and pulmonic vascular circuits on the right and left ventricles was observed in our patients with TGA. In simple TGA the LV empties into the low resistance pulmonic circuit while the RV ejects into the high resistance systemic circuit. Evaluation of RV function after the Mustard procedure has aroused particular interest because it has been uncertain if the RV can sustain systemic function for a normal life span. There was a prolonged RPEP and shortened RVET in our patients with TGA. This may have been the result of the increased afterload of systemic pressure, similar to acute animal experiments in which increased afterload is known to prolong PEP and shorten LVET.`3 The prolonged RPEP may also be a result of myocardial dysfunction and would indicate that the right ventricle is poorly adapted to assume the function of a systemic ventricle. The LVSTI in TGA differed in a manner that was appropriate for the decreased afterload, for when the LV emptied into the pulmonic circuit, ejection characteristics were similar to a normal RV (short preejection period and long ejection time). Circuilation volume 51, February 1975

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SYSTOLIC TIME INTERVALS/ECHOCARDIOGRAPHY

Our study has demonstrated that the noninvasive measurement of right, as well as left, ventricular STI can be accomplished with echocardiography. STI of the RV and LV were measured in patients with TGA and it was shown that ventricular STI were reversed when the pulmonic and systemic circuits were transposed. The ability to measure RVSTI echocardiographically should permit the noninvasive assessment of hemodynamic variables on RV function. Further refinement of this technique should allow the evaluation of the hemodynamic effects of elevated pulmonary vascular resistance, volume overload of the right ventricle, and right ventricular obstruction on RVSTI. In addition, it may now be possible to evaluate the results of subsequent surgical or pharmacologic interventions. References 1. WEISSLER AM, LEws is RP, LEIGHTON RF: The systolic time intervals as a measure of left ventricular performance in man. In Progress in Cardiology, Vol. 1. Edited by Yu PN, GooDWx IN JF. Philadelphia, Lea and Febiger, 1972, p 155 2. LEs Iis RP, LEIGHITON RF, FORESTER WF, WEISSLER AM: Systolic time intervals. In Non-invasive Cardiology. Edited by WEISSLER AM. New York, Grune and Stratton, 1974, p 301

309

3. WEISSLER AM, HA.RRIS WS, SCHOENFELD CD: Bedside techniques for the evaluation of left ventricular function in man. Am J Cardiol 23: 277, 1969 4. GR.ANIAK R, SHAH PM: Echocardiography of the normal and diseased aortic valve. Radiology 96: 1, 1970 5. GRANIIAK R, NANDA NC, SHAH PM: Echo detection of the pulmonary valve. Radiology 102: 153, 1972 6. MIUSTARD WT, KEITH JD, TRIUSLER GA, FolWLER R, KIDD L: The surgical management of transposition of the great vessels. J Thorac Cardiovasc Surg 48: 953, 1964 7. LEIGHTON RF, WEISSLER AM, WEINSTEIN PB, WOOLEY CF: Right and left ventricular systolic time intervals. Am J Cardiol 27: 66, 1971 8. AYGEN MM, BIRAUN-WALD E: The splitting of the second heart sound in normal subjects and in patients with congenital heart disease. Circulation 25: 328, 1962 9. BRAUNW ALD E, FISHNIA. AP, COIRNAUDO A: Time relationship of dynamic events in cardiac chambers, pulmonary artery and aorta in man. Circ Res 4: 100, 1956 10. HA\RRIS LC, WEISSLER AM, MANSKE AI, DANFOIRD BH, WHITE GD, HAXINIILL WA: Duration of the phases of mechanical systole in infants and children. Am J Cardiol 14: 448, 1964 11. GOLDE D, Bu.RSTIN L: Systolic phases of the cardiac cycle in children. Circulation 42: 1029, 1970 12. LEVi\ AM, LEANIAN DM, HANSON JS: Effects of digoxin on systolic time intervals of neonates and infants. Circulation 46: 816, 1972 13. WALLACE AG, MITCHELL JH, SKINNER NS, SAR.NOFF SJ: Duration of the phases of left ventricular systole. Circ Res 12: 611, 1963

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Measurement of right and left ventricular systolic time intervals by echocardiography. S Hirschfeld, R Meyer, D C Schwartz, J Korfhagen and S Kaplan Circulation. 1975;51:304-309 doi: 10.1161/01.CIR.51.2.304 Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1975 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524-4539

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Measurement of right and left ventricular systolic time intervals by echocardiography.

One of the noninvasive methods of evaluating left ventricular performance is the measurement of left ventricular systolic time intervals (LVSTI). Howe...
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