An echocardiogram,referred to casually as a cardiac echoor just echo, is an ultrasound examination of the heart.It is a safe and painless test that can be completed inless than an hour. The echocardiogram employs soundwaves to examine the heart’s structure and motion. Itcan produce detailed images of the heart’s chambersand valves. It is capable of measuring the size of thechambers to within small fractions of an inch as well asmeasuring the thickness of the walls of the heart. Theechocardiogram can also measure the pressure change(or pressure gradient) between the left ventricle and theaorta. Doctors commonly use the echocardiogram toassess the pumping function of the heart by measuringthe ejection fraction.
Normally, the heart ejects approximately 60 percent ofthe blood in the left ventricle every time the heartbeats. Patients with ejection fractions of approximately 40–45 percent have mildly depressed ejection fractions;patients with ejection fractions of about 30–40 percenthave moderately depressed ejection fractions; and pa-tients with ejection fractions in the 10–25 percentrange have severely depressed ejection fractions.
It is important to keep in mind that someone with anormal ejection fraction reading can still have heartfailure. Diastolic dysfunction is a term physicians use todescribe the effects of the heart muscle that has becomeso thick and stiff that the ventricle does not expand forblood coming in from the atrium. Therefore, the ven-tricle holds a smaller-than-usual volume of blood.While the percentage of blood pushed out in eachheartbeat is high (the ejection fraction), the amount ofblood pushed out in each heartbeat is low (the cardiacoutput). The patient suffers heart failure because thetotal amount of blood pumped isn’t enough to meet thebody’s needs.
- echocardiography images