Heart echocardiography analysis

Analysis of the Doppler spectrum

The diastolic Doppler spectrum of blood flow through the atrioventricular valves is recorded when a trial volume is placed in the center of the blood flow near the edges of valve flaps.

If the trial volume is too far in the ventricle, the spectrum will show an increase in early diastolic inflow and a decrease in the atrial component.

Precise installation of the trial volume provides a picture of the normal "M-shaped" Doppler spectrum of the atrioventricular valves. A higher initial peak characterizes the early diastolic influx into the relaxed ventricles and is called the E-wave (from early- early). The second, smaller, peak is caused by contraction of the atria and is called A-wave (from atrial - atrial).

The peak velocities E and A of the waves are used to calculate the E / A ratio. This ratio of rates depends on age, being high in young, it decreases with age. It also depends on heart rate and cardiac output: with an increase in heart rate, the diastole is shortened, and atrial contraction plays a big role in filling the ventricles. This is reflected in the Doppler spectrum by the increase in wave A, and as a result, the E / A ratio decreases. If the E / A ratio is abnormal in intact valves, this indicates a violation of diastolic ventricular function, for example, a violation of early diastolic relaxation or a decrease in ventricular compliance.

The outflow tract of the left ventricle and aorta

The blood flow through the LVEF and the aortic valve is best seen in the apical ghtakameric plane. The sensor should be installed so that the beam is directed as far as possible in parallel to the flow in the LVST. After receiving images in the B-mode, a color mode is activated that gives information about the blood flow. In systole, laminar blood flow from the sensor to the LVTH and through the aortic valve is normally determined. High blood flow velocity can cause blurring if the frequency shift exceeds the Nyquist limit.

To record the Doppler spectrum, place the test volume in the aorta right behind the valve. The normal spectrum from the aorta shows laminar systolic blood flow in the aorta with a sharp rise and a fall in its velocity. In diastole, regurgitant blood flow through the valve should not be determined, either on the color image, or on the Doppler spectrum.

The time integral of the velocity is the integral of the spectral curve or the area under the spectral curve. It is determined by planimetric analysis. S stands for the perfused aortic section and is determined by measuring the diameter of the aorta using the circle area formula. Since the radius is squared, even a small error in its measurement can lead to a large error as a result.

Right ventricular outflow tract and pulmonary artery

The blood flow for LMWH is assessed by examining the pulmonary trunk in the parasternal plane along the short axis at the root level of the aorta. As in the study of the aorta, the orientation is made according to the color regime, and the Doppler test volume is set in the center of the bloodstream, immediately behind the open valve. The spectrum is similar to that in the aorta, but the peak velocities are less.

Analysis of wall motion anomalies

Automatic segmental traffic analysis (ASAD) is a relatively new technique. Anomalies of heart contractions are detected automatically and correlate with their location on the heart wall. Using a high-resolution digital converter built into the system, the endocardial contours are recorded every 40 ms during the cardiac cycle and are charted in real time with color coding on the display. This color representation of segmental wall contractions remains on the monitor throughout the entire cardiac cycle and is updated with the onset of a new one.

Diseases of the valves

Aortic stenosis

The valve is thickened, markedly hyperechoic, there is a significant restriction of its movement. The image in the systole determines the turbulent blood flow in the ascending aorta distal to the aortic valve. There is concomitant mitral insufficiency of mild degree, revealed by a small color jet below the closed mitral valve. On the image in the diastole, the regurgitation flow (15c) in the LVST is additionally detected, as a sign of aortic insufficiency. The patient is an elderly woman with severe degenerative aortic stenosis. The Doppler pressure gradient is 65 mm Hg. Art.

Valve Prosthesis

The metal prosthesis is characterized by a hyperechoic signal and gives a reverberative artifact in the underlying atrium and acoustic shadows. Accelerated blood flow from the atrium to the ventricle can be seen on the left and right of the obliquely located valve disc.

Tissue dopplerography

Tissue dopplerography is a new technique that allows you to evaluate the motion of the heart walls by color coding of tissue movements in blue with the direction from the sensor and red in the direction towards it. This is achieved by using different filters. Thus, it is possible to better detect pathological wall movements, for example, in IHD, when stressful effects, for example, physical stress or the introduction of dobutamine lead to a decrease in blood flow through the affected artery and, as a consequence, regional myocardial dysfunction. Local wall contractions can be compared at rest and under stress tests, while simultaneously evaluating the cardiac cycle at different stages of stress echocardiography (for example, at different rates of dobutamine infusion).

Tissue dopplerography can also be used in the analysis of longitudinal contractile function of the myocardium. This is a sensitive marker of early myocardial dysfunction. Longitudinal shortening is best seen in the apical four-chamber plane when the test volume is located in the free walls of the right and left ventricles and in the interventricular septum.

Critical Assessment

Interest in echocardiography is due to the non-invasiveness of the method, the ability to perform it at any time and to repeat as often as necessary. Currently, echocardiography provides complete information about the anatomy and function of the heart. It can be used in outpatient settings, in an emergency situation and even in the operating room. This range of application is limited only by the fact that echocardiography can not be performed in all patients due to poor acoustic window, obesity or pulmonary emphysema. When using new techniques, for example, harmonic visualization, you can significantly improve the image quality. The visualization of the walls of the heart also improves with the use of ultrasound contrast preparations.

Not all cardiac structures (eg, coronary arteries and peripheral branches of the pulmonary arteries) can be adequately assessed by echocardiography. These vessels require other techniques, such as angiography, CT or MRI. On the other hand, echocardiography can provide additional functional information in the complex diagnosis of heart disease using other techniques.

Recent advances in echocardiography.

At present three-dimensional processing of echocardiographic images in real time has become available for evaluation of cardiac structures.

Blood flow in the coronary arteries can be assessed by echocardiography in the energy Doppler regime, not only in the proximal parts of the left and right coronary arteries.

The color estimate of the wall contractions facilitates the detection of the area of the anomalous function. Regardless of the contractions of the heart, you can determine the extensibility. In this case, signs of deformation of the myocardium in the form of systolic shortening and diastolic elongation can be revealed. These data allow assessing the overall and regional functions of the myocardium.

We should expect further improvements in the potential for the use of echocardiography for a non-invasive assessment of the morphology and function of the heart.

[1], [2], [3], [4], [5], [6], [7]