Stress Echo
218 Vivid S5/Vivid S6 User Manual
R2424458-100 Rev. 2
Quantitative TVI Stress echo analysis
The Vivid S5/Vivid S6 Ultrasound unit provides a Quantitative
TVI (QTVI) Stress analysis package based on Tissue velocity
information (TVI). The TVI data is stored in a combined format
with grey scale imaging during stress examination.
When selecting a template supporting TVI data acquisition, the
ultrasound unit will automatically store TVI information,
generally for the apical views of the stress examination.
The QTVI Stress analysis option currently applies only to
Dobutamine stress-echo.
Wall Motion Scoring remains the basis for the diagnosis of CAD
in stress echocardiography. QTVI Stress may be used as a
guidance tool to check this interpretation.
QTVI Stress is based on the assessment of peak velocity at
peak Dobutamine stress (see "References" on page 224. The
normal ranges have been validated in the "average" patient
presenting for stress testing. The velocity cutoff values for the
Vpeak measurement will not work in the following cases:
Velocity measure-
ments in mid and
basal segments of
the myocard will
contain contribu-
tions from the api-
cal region of the
myocard. E.g. if
measured value in a
mid segment is be-
low the cutoff value
for this segment
then this might re-
late to a reduced
function in the mid
or apical region.
• Submaximal stress (<85% predicted max HR)
• Patients at extremes of age (<40 or >70)
• Previous myocardial infarction/revascularization
• Previous heart-failure / cardiomyopathy / hypertrophy /
arrhythmia / aortic regurgitation
The velocity cutoff values are based on placing the sample
volume at center of each cardiac segment at start of systole,
the left ventricle myocardial segments are defined by the
American Society of Echocardiography 16 segments model.
However, the velocity cutoff model does not cover the apical
segments (due to low velocities and segment orientation), (see
side note).
Tissue Doppler does not have perfect site-specificity because
of tethering by adjacent segments. Thus, although an ischemic
segment has little thickening (and therefore could be expected
to show low velocity), measured velocity may be influenced by
WARNING
QTVI Stress analysis is meant as a guide to wall motion scoring.
Diagnosis must not be based on results achieved by QTVI Stress
analysis only.
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