Echocardiography refers to the imaging of the heart with ultrasound.
M-mode Echocardiography measures the thickness of the ventricular walls and the dimensions of the internal cavity of the ventricles. From these parameters indices of the ventricular contractility can be readily determined. Of these indices, fractional shortening is the most common.
Two-dimensional Echocardiography provides a wide overall view of the heart. It is ideal to assess the relative size of the four intracardiac chambers and the relationship of the thickness of the cardiac walls to the size of the chambers. It can also identify pericardial effusion. This mode of imaging may allow the identification of intracardiac shunts, prolapse of an atrio-ventricular valve leaflet, the obstruction of outflow of blood or the restriction to motion of a valve.
The Doppler examination detects blood flow throughout the heart, enabling the specific identification of valvular heart disease; ie, valvular insufficiency and valvular stenosis. As well, the Doppler examination enables the detection of intracardiac shunts; ie, atrial septal defects and ventricular septal defects. The Doppler examination also provides evidence of abnormal diastolic function, and reductions in cardiac output.
Echocardiography is of outstanding value to confirm a presumptive diagnosis of aortic stenosis or subaortic stenosis. In this disorder, short of cardiac catheterization, there is no other method available to confirm the existence of aortic stenosis.
This procedure is a completely non-invasive diagnostic test in all its various modalities. In the vast majoriity of cases even sedation is not required as an aid to perform this examination.