Echocardiography is a non-invasive technique that can detect the
presence of localized or generalized hypertrophy or thinning of the
myocardium of the left ventricle (LV) and the presence of regional
or global wall motion abnormalities associated with systolic
dysfunction. The application of transmitral Doppler analysis allows
the detection of abnormal filling patterns associated with LV
diastolic dysfunction.
The core employs two echocardiography systems, one for high
resolution imaging and a high throughput lower resolution imaging
system. Echocardiography can be performed on conscious as well as
anesthetized mice. In addition to imaging under basal conditions,
the mice may undergo stress testing following the administration of
dobutamine.
Low-Resolution Echocardiography. A 15 MHz linear-array transducer
(Sonos 5500, Agilent) is used for high throughput echocardiography
in conscious mice. Measurements include LV wall thickness in the
intraventricular septum and posterior wall, diastolic and systolic
LV diameter, and heart rate. Fractional shortening and ejection
fraction are computed as a measure of systolic function. This
system also allows for transmitral Doppler analysis that can detect
abnormal filling patterns associated with LV diastolic
dysfunction.
High-Resolution Echocardiography. The Vevo 2100 Imaging System
(VisualSonics) utilizes a ultra-high frequency 18-38 MHz
linear-array transducer with a digital ultrasound system for
superior imaging of mouse cardiac morphology and function as well
as Doppler analysis. Measurements include those described for the
low-resolution echo. In addition, the VevoStrain analysis software
provides a highly sensitive speckle-tracking based
echocardiographic imaging technique that offers quantitation of the
velocity of the walls, displacement, strain, strain rate, and time
to peak analysis.