Echocardiography (Ultra Sonic Cardiography)

By: Joe Hing Kwok Chu

Echocardiography is the method for making images of the heart using ultra sonic sound waves of frequency higher than the human ear can hear. The human body parts have different acoustical impedances. The internal structures of the heart have different densities. The sound waves that are reflected from the different parts of the heart are converted into images. Different software can be used to report the condition of the heart. Some software can be used for calculating the value of Stroke Volume, Cardiac Output, Ejection Fraction, etc., but in others the technicians or the cardiologists have to calculate them.

Echocardiography has been used in America during the last 25 years. The equipment is costly.

The term UKG (ultrasonic cardiography) is more commonly used in China. This technique has been used for research and clinical application since the 1960's in China, a pioneer in this field.

The values can be calculated as follows: (each letter does not represent a value; please see the abbreviation explanation.)

EDD³ - ESD³ = SV

SV x HR = CO

LV Ejection Fraction =[ (EDD³ - ESD³) / EDD³ ]100%

LV Fractional Shortening = [ (EDD - ESD) / EDD ]100%

Explanation of abbreviation:

ESD = end systolic dimension, also written as LVID_s;

EDD = end diastolic dimension, also written as LVID_d;

HR = heart rate;  SV = stroke volume;

CO = cardiac output;

TPR = total peripheral resistance;

EF = ejection fraction;

MVCF =mean velocity of circumferential fibershortening

If the EF figure is smaller than 50%,  the patient might be considered a candidate for bypass surgery.

Click here for samples of reports of Echocardiograms

Normal range of LVEF.

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