EHOKARDIOGRAFYYa (an echo, an echo + heart + to write Greek echo to Greek kardia with grapho,
to reap an isosconce) — the method of a research of structure and mechanical action of the heart based on registration of the reflected signals of a pulsed ultrasound. From E. distinguish an ultrasonic kinetomio-cardiography, at a cut Doppler change of frequency of constant ultrasound is used (cm. Dopplera effect), and also the Doppler ultrazonografiya allowing to obtain information on the direction, speed and character of a blood-groove in cardial cavities and in large vessels.
First experiences wedge, uses E. are reflected in Edler's works (I. Edler, 1955) and S. Effert with sotr. (1957), used the modified industrial defectoscopes to a research of heart. They described a normal echocardiographic picture of heart and an ekhokardiogramm at a stenosis of the left atrioventricular opening. From the middle of the 60th E. use for diagnosis of defects and tumors of heart, an exudative pericardis and other heart diseases, and also for a research of the sizes and functions of its departments. Since the 70th as in our country, and abroad E. became a widespread noninvasive diagnostic method of many heart diseases and assessment of function of a left ventricle.
Contraindications to use E. no. Absolute harmlessness allows to apply E. for a research of function of heart at a fruit, pregnant women and at newborns.
In a crust, time use several modifications of the devices working in the mode of the pulsed reflected ultrasound. This echo cardiographs, the hearts giving in a false manner the two-dimensional image (the true size of heart, and across — development of the movement of its structures in time down is defined); ultrasonic V-skane-ry, giving the two-dimensional image of heart made of many reductions (on average from 150); the sectoral scanners giving the two-dimensional image of heart in actual scale not only on distance but also on time. Two last groups of devices are called two-dimensional ekhokardiograf. A basic element of each device is the ultrasonic sensor supplied with a piezocrystal generating and perceiving ultrasonic fluctuations.
The principle of a method is that ultrasound with frequencies of 2 — 10 MHz sent by frequent impulses (to 1000 impulses in 1 sec.), gets into a body of the person, is reflected in limit of the section of environments with various ultrasonic resistance and is perceived by the device. The image of echo signals from structures of heart in each position (ekhokardiogramm) is reproduced on the screen of an oscillograph and is registered on a film or ultra-violet paper. The two-dimensional image is registered on a film in strictly set phases of a cycle of cordial reduction (thanks to synchronization of the image with a tooth R electrocardiograms). It can be recorded with the videorecorder for the subsequent time-lapse analysis: All procedure of a research usually does not exceed 10 — 15 min. At known in a body of the person and time between parcel and perception of an impulse the distance between the sensor of the device and the reflecting structure or between two and more reflecting structures is possible to define rates of propagation of ultrasound. As the frequency of sending of impulses considerably exceeds the speed of the movement of separate structures, napr, valves of heart, this speed can be determined rather precisely.
During the carrying out E. the patient lies on spin, an upper half of a trunk is raised approximately on 30 °. The sensor of an ekhokardiograf is installed on the left edge of a breast, in the third or fourth intercostal spaces (depending on a constitution of the patient); at the same time the shift of an ultrasonic bunch within the sector covering heart from a top to the basis is possible. Convenient placement of the sensor is promoted by its small diameter (0,7 — 2 cm). Changing a tilt angle of the sensor of rather chest wall, i.e. directing an ultrasonic beam in various directions, the researcher can locate practically all structures of heart. Conditionally distinguish four main positions of the sensor (fig. 1, a). During registration of an ekhokar-diogramma the sensor is continuously displaced from the registered position to following, detaining him the movement at detection of the interested doctor of the phenomenon. When the bunch of ultrasonic waves is directed directly to a top of heart (position I), it passes through a cavity of a left ventricle at the level of a back papillary muscle and through an insignificant part of a cavity of a right ventricle. Shift of a bunch up and medially (position II) allows to visualize walls of a left ventricle at the level of an attachment of shutters of the mitral valve, shutters and some other structures. Further shift of a bunch in the same direction (position III) gives the chance to well see a front shutter of the mitral valve and partly a cavity of the left auricle. Shift of a bunch of ultrasonic waves in the direction to the basis of heart (position IV) allows
Fig. 1. The scheme of registration usual «two-dimensional» ekhokardiogramm with the course of bunches of ultrasonic waves through structures of heart (a), the diagrammatic representation of an ekhokardiogramma of the working heart (b) and the image of an original normal ekhokardiogramma on sensitive paper (v): — the ultrasonic
sensor (the generator — a receptor of ultrasonic fluctuations); 2 — a front wall of a thorax; 3 — a breast; 4 — a front wall of a right ventricle; 5 — a cavity of a right ventricle; 6 — an interventricular partition; 7 — a cavity of a left ventricle; 8 — a cavity of an aorta and a shutter of the aortal valve; 9 — a front shutter of the mitral valve; 10 — a back shutter of the mitral valve; 11 — a back papillary muscle; 12 — back, a wall of a left ventricle; 13 — a cavity of the left auricle; 14 — a back wall of the left auricle; 15 — an epicardium; 16 — a pericardium; 17 — lungs. I, II, III, IV — the positions of the sensor corresponding to the course of a bunch of ultrasonic waves; EKHONG — an ekhokar-diogramma, the ECG — the electrocardiogram in the second standard lead.
to receive the reflected echo signals from walls and valves of an aorta, and also from walls of the left auricle. For a research of the tricuspid valve the beam of the sensor is directed me-dialny by places of a location of the mitral valve, i.e. transsternalno. For a research of the valve of a pulmonary trunk the beam is displaced a little up and lateralno from the usual place of a location of an aorta.
Normal ekhokardiogramma. As the ekhokardiogramma represents the image of moving structures of heart on moving paper, it has an appearance of a number of curves, each point to-rykh at a given time reflects position of structures of heart at the same moment. The mark of time in an ekhokardiogram-ma is usually presented by vertical straight lines in 0,5 sec. In fig. 1 the diagrammatic representation of an ekhokardiogramma (1, b) and a normal original ekhokardiogramma is given (1, c). Echo signals from
front and back walls of an aorta are displayed by two «parallel» curves; between them curves from moving shutters of the aortal valve are located. During a systole echo signals from shutters form the figure reminding a rhombus or a parallelogram; during a diastole they are densely closed. Below reflection from a back wall of an aorta the cavity of the left auricle limited from below to its back wall is defined. The movements of the mitral valve are displayed by typical echo signals. From its front shutter during a diastole echo signals are displayed M-obraz-noy curve that reflects changes of a blood-groove in phases of bystry filling, the reduced filling and a systole of the left auricle. The back shutter of the valve moves in an antiphase to a lobby, but with a little smaller amplitude. During a systole of a left ventricle of a shutter of the valve are close. The cavity of a left ventricle is limited from above to an interventricular partition, at a cut both endocardial surfaces, from below — a back wall of a left ventricle where endocardial and epicardial surfaces are defined are defined.
Echocardiographic diagnosis of heart diseases is based on identification of changes of the sizes, forms and the movements of separate structures of heart.
At a stenosis of the left atrioventricular opening (see the Heart diseases acquired) echo signals from moving shutters of the mitral valve change: during a diastole instead of a normal M-shaped curve the P-shaped curve (fig. 2) is noted; the back shutter of the mitral valve moving normal
Fig. 2. Ekhokardiogramma (EKHOYANG) and the electrocardiogram in the second standard lead (ZhG) at a stenosis of the left atrioventricular opening and fibrosis of shutters of the mitral valve (the sensor of an ekhokardiograf is in the fixed situation): shutters of the valve, lobby (1) and back (2), are thickened, move in one phase (the curve of the movement of a front shutter instead of two normal tops has «plateau»).
in an antiphase to a lobby, moves synchronously from a lobby or it is not mobile. Existence of fibrosis and calcification of shutters is expressed on an ekhokar-diogramma by a thickening of reflection from shutters. Expressiveness of a stenosis can be estimated as on the speed of cover of a front shutter during a diastole, and by results of direct measurements of the sizes of a valve opening at a two-dimensional echocardiography. Insufficiency of the mitral valve has no such accurate diagnostic characters therefore in this case the diagnosis is made on the basis of indirect signs (expansion of a cavity of a left ventricle, left auricle etc.). Important information is given by E. at inspection of patients with mitral valve prostheses: according to its data it is possible to judge as
function of a prosthesis, and, in a certain measure, existence of trombotichesky deposits on the valve.
Typical echocardiographic changes come to light at a prolapse of the mitral valve (fig. 3, and, b). At this syndrome during a systole the movement of one or both shutters of the valve towards the left auricle is noted. By means of E. it is possible not only diagnose a prolapse, but also to establish in what part of a systole it occurs, its expressiveness, quantity of the shutters participating in a prolapse. Detection of an anguish or separation of a papillary muscle at an acute myocardial infarction is close to diagnosis of a prolapse.
The principles of echocardiographic diagnosis of defects of tricuspid and mitral valves match. At a research consider that the movement of shutters of these valves on an ekhokardiogramma differs in a form a little. To distinguish their
Fig. 3. Ekhokardiogramma of the patient with a prolapse of shutters of the mitral valve (a) and the diagrammatic representation of an echocardiographic picture of the movement of shutters of the mitral valve (b) is normal (/) and at their prolapse (II): 1 t —
the first cardiac sound; Friday — the second cardiac sound; I \front shutter of the mitral valve; 2 — a back shutter of the mitral valve; 3 — a cavity of the left auricle; 4 — a cavity of a left ventricle; 5 — the late systolic noise characteristic of a prolapse of the mitral valve; EKHOKG — an echo cardiogram; The ECG — the electrocardiogram in the second standard lead; FKG — the phonocardiogram; at a prolapse of shutters at the end of a systole their discrepancy is visible (it is designated by shooters).
the arrangement of valves of rather interventricular partition helps (a trikuspida the lny valve higher than a partition, mitral — below). In addition to diagnosis of a stenosis of the right atrioventricular opening and the expressed insufficiency of the tricuspid valve diagnosis of the combined stenosis of the left and right atrioventricular openings is possible.
Diagnosis of a stenosis of the mouth of an aorta is based on identification of a thickening of shutters of the aortal valve and decrease in extent of their discrepancy in a phase of a systole (fig. 4, and, b). Insufficiency of the aortal valve comes to light in the presence of high-frequency oscillations of a front shutter of the mitral valve in a phase of a diastole as a result of blow of a stream
of Fig. 4 to it. Ekhokardiogramma (EKHOKG) is normal of the aortal valve (and) and at an aortal stenosis (b) and the electrocardiogram (EMG — in the second standard lead): 1 — the period of close shutters; 2 — the period of disclosure of the valve.
regurgitiruyushchy blood. At the expressed aortal regurgitation oscillation not only a front, but also back shutter of the mitral valve and even an interventricular partition is possible.
The research of the valve of a pulmonary trunk allows to reveal its stenozirovaniye (including an infundibulyar-ny stenosis of the mouth of a pulmonary artery), and also to approximately estimate expressiveness of hypertensia of a small circle of blood circulation at its existence.
For diagnosis of an exudative pericardis (see) a method E. is one of the most reliable. A pathognomonic sign of availability of liquid in a cavity of a pericardium is the discrepancy of leaves of an epicardium and pericardium (fig. 5) noted on an ekhokardiogram-ma. On extent of this discrepancy judge not only availability of liquid, but also its approximate quantity.
Important information is given by E. for diagnosis of mobile tumors of heart, in particular a myxoma of the left auricle (see Heart, tumors). At the same time on an ekhokardiogramma reflection of impulses of ultrasound from foreign education in a cavity of an auricle is registered, and in the period of a diastole the tumor can be revealed also between shutters of the mitral valve. Two-dimensional E. allows not only establish existence of a myxoma, but also to determine its sizes. Cases of diagnosis by means of E are described. bilateral myxomas of the left and right auricle.
In a complex with other invasive and noninvasive methods E. apply to diagnosis of different types of a cardiomyopathy (see). At a congestive (di-latatsionnoy) cardiomyopathy эхо-^ардиографически diffusion expansion of all cardial cavities without the expressed thickening of a wall of heart,
Fig. 5 is defined. Ekhokardiogramma (EKHOKG) and the electrocardiogram (an ECG — in the second standard lead) at a vypotny pericardis: 1 — a cavity of the left auricle; 2 — an aorta; z — the left lung which is pushed aside from an epicardium by an exudate; 4 and 11 — liquid in a cavity of a pericardium; 5 — a parietal layer of a pericardium; 6 — an epicardium; 7 — a cavity of a left ventricle; 8 — a front shutter of the mitral valve; 9 — an interventricular partition; 10 — a cavity of a right ventricle.
and also falloff of indicators of the central hemodynamics and sokratitelny ability of a myocardium. At an idiopathic hypertrophy of a myocardium the expressed concentric hypertrophy of a myocardium without essential expansion of cardial cavities is defined. Changes of an ekhokardiogramma at a subaortal stenosis (fig. 6) are most specific: along with the expressed asymmetric hypertrophy of an interventricular partition the shift of shutters of the mitral valve towards a partition and their paradoxical protrusion in the same party in a phase of a systole is defined.
Important information on a condition of a myocardium is given by E. at coronary heart disease (see). By means of usual E. define existence of zones of a dyssynergia (an akineziya, a hypokinesia, dyskinesia etc.), and two-dimensional E. allows to establish also their extent.
Fig. 6. Ekhokardiogramma (EKHOKG) registered at the fixed position of the sensor from the second (17) and third (III) positions and the electrocardiogram (an ECG — in the second standard lead) the patient with an idiopathic hypertrophic subaortal stenosis: 2 — a reinforced mezhzheludochky partition; 2 — the reduced cavity of a left ventricle;
3 — a back shutter of the mitral valve;
4 — a front shutter of a mitral kl *
Use of an echocardiography for assessment of function of a left ventricle of heart. Possibility of measurement by means of E. the perednezadny size of a left ventricle created premises for development of ways of rather exact scoping of a left ventricle in phases of a systole and a diastole, and also calculation of nek-ry other indicators, in particular the average speed of circular shortening of fibers of a myocardium, edges depends on its sokratitelny function. In different phases of a cardial cycle determine a stroke output of a left ventricle and fraction of emission by the established size of volumes of a left ventricle. Besides, comparison to data of autopsy showed that the distance between endocardial and epicardial surfaces of a back wall of a left ventricle on an ekhokardiog-ramma corresponds to thickness of a myocardium of a left ventricle, knowledge a cut helps to determine the mass of a myocardium of a left ventricle. These opportunities E. served as justification for its use with a research objective of function of a left ventricle, including in the course of various functional trials (conducted-ergometriya, orthostatic and An-tiortostatichesky influences, izometrichesky loadings etc.), and for studying of action on the central hemodynamics various pharmakol. means (cardiac glycosides, peripheral vazvdilatator, diuretic drugs, etc.).
Use of a method E. has certain restrictions of technical and methodical character. It is not possible to locate qualitatively structures of heart at patients with the expressed emphysema of lungs and narrowing of intercostal spaces. Thereof at 8 — 15% of elderly people the echocardiographic research is almost impossible.
Perspectives of development of a method E. are connected with further improvement of devices for E. and implementation of the computer equipment, with the help a cut assessment of function of relaxation of a myocardium and local functions of a wall of a left ventricle, and also function of the left auricle is possible.
See also Ultrasonic diagnosis.
Bibliography: Zaretsky V. V., Bob
of V. V. k and Olbiisky JI. I. Clinical echocardiography, M., 1979; Mukharlyamov H. M and Belenkov Yu. N. Ultrasonic diagnosis in cardiology, M., 1981; The Guide to cardiology, under the editorship of E. I. Chazova, t. 1 — 4, M., 1982; E d 1 e of I. The diagnostic use of ultrasound in heart disease, Acta med. scand., suppl. 308, p. 32, 1955; Feigenbaum H. Echocardiography, Philadelphia, 1981.
BB. H. Belenkov.