 |
| Fig. 16 |
Typical M-mode echocardiographic recordings from a patient with
dilated cardiomyopathy are shown in (Fig.
16). The small separation of the mitral valve leaflets suggests
that there is low cardiac -output. This appearance is known as
the "fishmouth" configuration and is characteristic of such severe
low flow states.
 |
| Fig. 17 |
In some patients a `hesitation' in the closure of the mitral
valve leaflets at the onset of systole can also be seen (Fig.
17). Though the exact cause of this sign is uncertain, provided
that the ECG P-R interval is normal, it is associated with significant
elevation of left ventricular end-diastolic pressure.
 |
| Fig. 18 |
There is a lack of motion of the aortic root and reduced aortic
cusp separation, which give further evidence of low cardiac output.
The left atrium may be enlarged, due to elevation of ventricular
filling pressure. As shown in (Fig.
18), the left ventricular cavity is large with thin walls.
Extreme dilatation of the left ventricle can stretch the mitral
valve annulus and cause the valve to become incompetent.
 |
| Fig. 19 |
In most cases of dilated cardiomyopathy there is a globular shape
to the ventricle and wall motion is uniformly reduced. This can
be visualized by two-dimensional echocardiography (Fig.
19). Note that there is little change in ventricular diameter
from diastole to systole, a sign that overall left ventricular
ejection fraction is quite low.
2004