)'ournal o f the American Socicu, o f Echocardiography

Volume 9 N u m b e r 3 Abstracts 379

102J F L O W V O L U M E M E A S U R E M E N T IN S M A L L VESSEL USING A DIGITAL D O P P L E R C O L O R F L O W MA PPI N G M E T H O D : AN IN V I T R O S T U D Y Satoshi Aida, BS, Takahiro Shiota, MD, Timothy Thigpen, BS, Hiroyuki Tsujino*, MS, David J. Sahn, MD, Oregon Health. Sciences. Univ. Portland, OR, *Toshiba Corp. Tochigi, Japan

The aim of our study was to investigate the applicability of a new automated cardiac flow measurement method for quantifying smaller vessel flows in an in vitro model. A thin latex tube (diameter = 6.4 mm) was obliquely embedded inside a container filled with agar-graphite, which produced ultrasound attenuation and texture similar to soft tissue (-0.5 dB/cm.MHz). Color Doppler images of the flow in the tube were acquired by Toshiba Power Vision SSA-380A using 3.75, 5.0 and 7.0 MHz sector probes. Two steady flows (7.4 and 14.6 ml/sec) within the tube were measured at different depths (2 - 10 cm) from the transducer. Results were compared with reference flow meter data (figure). In a high flow setting, measured flow rates at 2 and 4 cm depth using a 7 MHz probe agreed well with those by the flow meter, overestimating by 12 %. The data from 5 MHz also agreed well with the reference at shallow area (2 - 4 cm) although they overestimated by nearly 35 % at deeper region (5 - 7 cm). In contrast, flow rates obtained using 3.75 MHz substantially overestimated the reference values mine than 40 % and the nverestimation increased as the depth increased, except 10 cm depth at which position only poor quality color Doppler data were acquired mainly due 1o ultrasound attenuation. The same tendency was observed for a low flow setting. These overestimations appear to be due to the expansion of the imaged color area based on the deterioration of the lateral resolution which depended on the ultrasound frequency and the depth. The automated flow measurement method when used with high frequency ultrasound at shallow depth appears promising for quantifying small vesseI flows and may work well for baby hea~ studies.

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102L EVALUATION OF LEFT VENTRICULAR DIASTOLIC FUNCTION IN HYPERTROPHIED HEARTS USING DOPPLER T I S S U E IMAGING Tabata T MD, Oki T MD, Iuchi A MD, Yamada H MD, Manabe K MD, Sasaki M MD, Kawahara K MD, Niki T ,x/if), Fukuda N MD, Ito S MD, Toknishima University, Tokushima, Japan

[Background] The left ventricular (LV) diastolic dysfunction has been assessed by combined analysis of the transmittal and p~monary venous ~low velocity patterns obtained from pulsed Doppler echoeardiography, ttowever, the transmittal flow velocity shows the "pseudonormalization" panern when the LV end-diastolic pressure (LVEDP) is elevated. [Purpose] The purpose of this study is to assess the IN diastolic l~nction in h3pertrophied hearts using pulsed Doppler tissue imaging 0337) method, and to evaluate the effects of LVEDP on its wall motion velocity pattern. [Methods[ We recorded the transmittal flow velocity pattern by pulsed Doppler echocardiography, and also recorded the subendocardial motion velocities at the middle of LV posterior wall (PW) in paraster~ml long-axis view using DTI method. Study population consisted of 28 patients with asymmetric septal hypertrophic eardiomyopathy, 15 with hypertensive heart disease and 20 normal controls (Gr-N). The hypemophiedhearts were divided into G'r@N (LVEDP > 15 mm Hg, n=81 and GrRF (LVEDP < 15 aim Hg. n=351. [Results] 11 The ratio of the peak atrial systolic to early diastolic transmitral flow velocities in Gr--PN was less than 1 (pseudonormalization pattern) and that in Gr-RF was 1 or more. 2) The peak early diastolic wall motion velocity (Ew) of the PW in the Grs-PN (p<O.0001) and -RF (p<0.01) were smaller than that in Gr-N. 3) The time to peak Ew tYom the sevond heart sound (IIA-Ew) in the Grs-RF (p<0.01) and -PN (p<0.001) were longer than that in Gr-N. 4) The peak atrial systolic wall motion velocity (Awl of the PW in Gr- RF did not driller from that in Gr-N, although there was a significant differtalce between Grs-PN aad -N (12<0.00011. 51 "Itle time to peak As' firm the onset of the P wave of ECG (P-Awl was longer in Gr-PN than in Grs-RF (p<0.0001) and -N (p<0.0001)

Gr-N Gr-RF Gr-PN

Ew (cnz~ls) 15.2 +2.9 11.0 + 4.7 8.7 +_ 1.8 Aw(em/s) 6.1 + 2.1 6.7 + 2.2 4.2+1.0

nA-Ew (msec) 130 + 14 151 + 35 170 + 30 P-Aw (msec) 133 + 14 145 + 12 163 + 14

LVEDP (ram Hg) 12+ 4 21 +_ 5

[Conclusion] Pulsed DTI imaging may provide new insights into LV early diastolic relaxation and hemodynamic events between LV and left atrium dtuing end- cliastole in hypertrophied hearts even under the condition of elevated LVEDP.

102I< MYOCARDIAL WALL VELOCITIES ASSESSED BY COMPUTERIZED COLOR DOPPLER TISSUE IMAGING IN CONSCIOUS DOGS. EFFECTS OF DOBUTAMINE. D. Pelhirin MD, A. Berdeaux MD, L. Cohen PhD, JF. Giudicelli PhD, S. Witchitz MD, C. Veyrat MD, Htpital de Bic~tre, Facult6 de M6decine Paris Sud, Faculte Paris-Dauphine, CNRS / lnserm UI41.

To assess the physiological characteristics of intra myocardial velocities at baseline and after dobutamine, 14 conscious chronically implanted dogs were investigated. Simultaneous invasive hemodynamics were performed. Dogs were studied at baseline and after steady state dobutamine infusion (I0 pg/kg/min). Doppler Tissue Imaging (DTI) consisted of color M Mode recordings of the left ventricular posterior wall in the short axis view. Eight vertical color bands were individualized throughout a cardiac cycle on digital images: Pre-ejection period (PEP), early, mid, end Systole (eaS, mS, eS), isovohimie relaxation (IR), rapid (El, slow (roD) and late (A) filling periods. Each band was divided into subendocardial, mid wall and subepieardial layers. Using a personal computer connected with the ultrasound machine the mean myocardiaI velocities (MMV) were automatically measured every 4 ms. MMV were positive in systole and peaked in mS. They were negative in diastole and peaked in caD. The highest MMV were observed in the snbendocardium. Peaks of the MMV (PMMV, ram/s) in all phases of a cardiac cycle in subendocardium were the following PEP 10.8_+29.9, eaS 49.2_+18.8, mS 61.7_+14.9, eS 39.4+_11.8, E -107.3_+30.5, mD -15.0+15.2, A -16.9-+14.5. A significant decrease in PMMV from subendo to subepicardium occurred throughout a cardiac cycle except during PEP and roD. This staircase pattern transmural velocity gradient was physiological and maximal during E. Dobutamlne induced a significant increase (p<0.001) in HR ( 130_++9 vs 99_+i2 ) and in subendocardial MMV mainly during systole which peaked in eaS ( 97.0+36.9 ) compared to mS at baseline. The transmural velocity gradient significantly increased during eaS ( 56.8+33.6 vs 19.7+25.2 at baseline) and during E ( 65.8_+34.5 vs 31.9+-27.9 at baseline ) due to higher increase in subendocardlal than in subepicardial velocities. DTI provides a new way to assess regional myocardial function by means of a computerized analysis which may be performed on line.

102M CALCULATION OF TIME-VELOCITY GRADIENT BY A NEW TISSUE DOPPLER ECHOCARDIOGRAPHY ANALYSIS SYSTEM AS AN INDEX OF REGIONAL LEFT VENTRICULAR FUNCTION Jobm Gorcsan llI MD, Christine M. Mahler MS, William E. Katz MD. University of Pittsburgh, Pittsburgh, PA.

The progression myocardial velocity from epieardial to endocardial surfaces has been defined as the velocity gradient. The advantage of the velocity gradient to assess regional LV function is its ability to determine myocardial thickening velocity independent of translational motion. Although peak systolic gradient values have been reported recently from single frame images, the velocity gradient has not been assessed as a function of time. Accordingly, 8 normal volunteers, aged 32±4 yrs, had tissue Doppler imaging studies (Toshiba SSA-380A) performed at baseline and during increases in contractility induced by dobutamine 5 p.g/kg/min. TDI color M-mode images were acquired with a frame rate of 300Hz and a velocity range of~ 14.2 era/see and recorded on a PC through a customized interface with the echo system. Velocity values were determined by a program (Toshiba prototype) which converted color-coded TDI velocity data into a digital matrix (35 pixels/cm x 50 pixels/100 msec). Examples of posterior wall time-velocity gradients from the onset of systole through early diastole appear below.

~ 0 . . . . .

~-4] r 5pg/kg/min ~ v[

-s' i~0 ' ~e~ 4dO " 160 '~se,=' 40b "

Baseline peak systolic gradients were 3.04 ± 0.86 see -l, systolic time-gradient integral were 0.38 ± 0.19, peak early diastolic gradients ware 5.88 a: 2.07, and early diastolic time-gradient integrals were 0.32 ± 0.14. Significant increases occurred with 5 gg/kg/min of dobutamine in the following: systolic gradient to 5.14 ± 1.93 see l*, systolic time-gradient integral to 0.62 :t: 0.29', and early diastolic time-gradient integral to 0.54 a: 0.22* (*9<0.05 vs. baseline). Time-velocity gradient by TDI may be useful to determine systolic and early diastolic regional LV function independent oftrar slation~! motion.