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Atlas of Human Body Ultrasound Scanning_ Methods and Diagnostic Applications ( PDFDrive ).pdf
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6  Echocardiography

73

 

 

1.3\ The Parasternal Left

Ventricular Long-Axis-View

M-Mode, Echo Pattern of Left

Ventricle

Fig. 6.3  The parasternal left ventricular long-axis-view M-mode, echo pattern of left ventricle

1.3.1\ Scanning Method

The patient lies flat or on the left side. The transducer is placed at the area about 1–2 cm away from the left sternal edge (fourth intercostal space).Along the long axis of heart, the M-mode cursor passes through the chordae tendineae of mitral valves.

1.3.2\ Section Structure

From the near to the distant, M-mode tracings present the following anatomical structures: chest wall, right ventricle, interventricular septum, left ventricle, chordae tendineae of mitral leaflets, and left ventricular posterior wall.

1.3.3\ Measuring Method and Normal Value

The anterior–posterior diameters of right and left ventricles can be obtained at the chordae tendineae of mitral valve level. According to the phase decided by synchronous electrocardiogram, left ventricular systolic diameter is measured at the point behind T wave slightly or on the highest point of M-mode trace of the left ventricular posterior wall at systolic end, while left ventricular diastolic diameter is measured on the R wave or at the lowest point of M-mode trace of the left ventricular posterior wall at diastolic end.

Thickness

of right ventricular anterior wall

is

4 ± 1.2

mm. Right ventricular diameter

is

15 ± 5.3 mm. Interventricular septum diastolic thickness is 9.7 ± 2.2 mm. Left ventricular diastolic or systolic diameter is 45 ± 15 or 30 ± 10 mm. Left ventricular posterior wall diastolic thickness is 9.3 ± 2.3 mm. A ratio of the interventricular septum thickness to the left ven-

tricular

posterior

wall

thickness

is

1.03 ± 0.07 mm.

 

 

 

1.3.4\ The Clinical Application

This is a standard view to measure the diameters of left and right ventricles, from which dimension of the ventricles, a ratio of left ventricle to right ventricle, the ventricular wall thickness, motion amplitude of the ventricular walls, systolic increasing rates of interventricular septum, and left ventricular posterior wall are seen.