CARDIOGRAPHY

From Big Medical Encyclopedia

CARDIOGRAPHY (Greek kardia heart + grapho to write, represent) — registration in a graphic form of various manifestations of cordial activity. In a broad sense the term «cardiography» has collective value and combines group of the techniques of a research of heart connected with graphic registration of its activity. Treat such techniques, e.g. ballistokardiografiya (see), echocardiography (see), electrocardiography (see), magnetocardiography (see), a reokardiografiya (see. Reografiya ), phonocardiography (see), dinamokardiografiya (see), etc.

In narrow sense this term is applied to designation of techniques of registration of mechanical oscillations of a chest wall (see. Kinetokardiografiya , Seysmokardiografiya ) or work-related movements of intratorakalny pericardiac educations of heart.

In modern literature the term «cardiography» is often used as a synonym of the term «apekskardiografiya» (a technique of registration of an apical beat of heart).

Development of techniques of registration of precardiac mechanical oscillations is caused by requirement experimental and especially a wedge, medicine in obtaining information on cardiodynamics without opening of a thorax and without catheterization of cardial cavities. For the first time the apical beat of heart — an apekskardiogramm (AKG) was registered at the person in 1863 by E. Marey by means of a stethoscope as the perceiving device connected by a pneumatic system to the capsule of the registrar. Further for record AKG the various perceiving devices were designed.

Use of optical techniques of registration at the beginning of 20 century gave more accurate account of the fluctuations of a chest wall caused by reductions of heart.

the Normal apekskardiogramma (AKG) registered synchronously with the electrocardiogram (ECG) and the phonocardiogram (FKG): and — the wave corresponding to an auricular systole; b — with — the raising of curve AKG reflecting an apical beat; the break of a curve in a point with corresponds to the beginning of a mechanical systole of ventricles; the tooth of d reflects the beginning of the period of exile of blood from ventricles; e — f — the plateau connected with pressing of heart to a chest wall; f — h — the descent of curve AKG corresponding to relaxation of ventricles of heart; the break of a curve reflects the moment of closing of semi-lunar valves of heart in a point of g; raising of h — % is connected with bystry filling of ventricles.

For record AKG various systems capable to perceive local movements are offered. The perceiving devices strengthen on a thorax directly over the place of a clear pulsation of an apical beat. It is reasonable to make record AKG in position of the examinee on the left side. During record the examinee shall hold the breath on an incomplete exhalation. Registration is made synchronously with one or two accompanying curves characterizing some periods of a cardial cycle, napr with an ECG and FKG (fig).

AKG represents the periodic curve consisting of one big positive wave occupying an initial part of each cycle of cordial reduction.

This main systolic wave is preceded by small rise and.

The wave and on time matches the termination of a tooth of P on an ECG with an atrial wave on the phlebogram and with the IV tone on FKG. Therefore, this wave corresponds to an auricular systole.

In a point of b on AKG sharp raising of a curve begins. This point will be spaced from a tooth of Q on an ECG on 0,015 — 0,03 sec. and usually happens synchronous to the beginning of the first low-frequency component I of tone on FKG. Thus, the interval from a tooth of Q on an ECG to a point of b on AKG characterizes by itself electrokinematic latency of heart.

Raising of b — e on AKG arises in connection with formation of an apical beat. On this rise the small break with, synchronous from the beginning of high-frequency fluctuations of the I tone is found. On this basis the point with is considered as the beginning of a phase of izovolyumichesky reduction or a mechanical systole, and the interval of b — with characterizes so-called apparent time of asynchronous reduction of a ventricle.

On AKG the tooth of d connected with the beginning of the period of exile of blood from heart sometimes comes to light. In these cases on AKG it is possible to calculate a phase of izovolyumichesky reduction of heart (an interval with — d).

Fiziol, value of a point of e on the ACRE remains not quite clear. The e — f plateau forms on AKG in connection with pressing of heart to a chest wall during the period of exile.

The descending part of AKG in the range of f — h arises in connection with relaxation of a myocardium. The point of f arises for 0,02 — 0,04 sec. prior to the beginning of the II cardiac sound. This point is considered as the end of a mechanical systole of ventricles and, therefore, as the beginning of the period of relaxation. Heart at this moment departs from a chest wall, and the curve begins to decrease.

At the beginning of an interval of f — h the break of g, synchronous from the beginning of the II cardiac sound can be found. It follows from this that in a point of g the mechanical processes connected with closing of valves of an aorta and a pulmonary trunk receive reflection. On this basis it is considered to be a point of g the end of the protodiastolic period and the beginning of a phase of izovolyumichesky relaxation. Therefore, the interval of f — g reflects duration of the protodiastolic period.

The point of h on AKG matches as it is considered to be, opening of the mitral valve. On this basis the interval of g — h is considered as a phase of izovolyumichesky relaxation of a left ventricle. Raising of h — i is connected with bystry filling of ventricles, however strict fiziol, the evidence to it it is not produced yet.

Thus, the AKG some elements correspond to certain phases of a cardial cycle. However not all of them receive clear reflection on all records of a curve of an apical beat. It is connected with the fact that the push is differently projected on a chest wall.

When the apical beat is projected by hl. obr. on an edge, but not in a mezhreberye, it poorly influences the perceiving device of the cardiograph. As a result of AKG at different persons, and also at different records at the same person can significantly differ in a form. Polymorphism of AKG can be connected also with the different force of pressing of the sensor to a thorax, variations of its form, different thickness of a hypodermic. It is also necessary to consider an inertance in transfer of a power impulse through a chest wall to the perceiving device of the device. All this complicates quantitative assessment of contractility of heart on amplitude characteristics of AKG. Therefore the technique of AKG is applied in clinic of hl. obr. for assessment of phases of a cardial cycle on time frames between the described points of AKG in comparison to the ECG and FKG corresponding elements.

One of extrathoracic techniques of registration of cordial reductions is connected using the capacity microphone installed in the IV mezhreberye which perceives fluctuations of very low frequency. This technique received the name «vibrocardiography». The vibrocardiogram is essentially option of ultralow-frequency FKG.

Nek-roye distribution was gained by also anemic techniques of registration of intratorakalny reflection of cordial reductions — ezofagokardiografiya (see) and pneumocardiography (cardiopneumography, pulmokardiografiya).

The technique of a pneumocardiography is based on use of the air filling lungs and airways as transmission environment for transfer of the mechanical processes caused by action of the heart. The most informative physical. the size registered on the pneumocardiogram is the speed of change of pressure in respiratory tracts.

The device for a pneumocardiography — the pulmokardiografichesky prefix — contains the perceiving link in the form of a mouthpiece with the pipeline and the metering device in the form of the electromanometrical converter sensitive to the speed of change of pressure. For ensuring control of the respiratory mode necessary for selection of a signal, the device is supplied with the inflated rubber bag. Record of a curve is kept when the examinee makes a quiet exhalation in a special elastic cylinder with a high pneumatic resistivity.

The pneumocardiogram represents quite polymorphic curve, teeth a cut can be correlated to various phases of a cardial cycle. Amplitude of a curve depends at most cordial reduction that is proved by its increase at physical. to loading. For a wedge, researches the pneumocardiography is practically not applied.



Bibliography: Andreyev L. B. and Andreyeva of N. B. Kinetokardiografiya, Rostov N / D., 1971, bibliogr.; Bayevsky R. M. Physiological measurements in space and a problem of their automation, M., 1970, bibliogr.; Karpman V. L. Phase analysis of cordial activity, M., 1965, bibliogr.; Aranese I. E. Akseleratsionnaya kinetokardiografiya, M., 1973, bibliogr.; Savitsky H. H. Biophysical bases of blood circulation and clinical methods of studying of a hemodynamics, L., 1974, bibliogr.; Tumanovsky M. N., etc. A method of a contactless kinetokardiografiya, Bulletin Ekspery, biol, and medical, t. 67, No. 11, page 121, 1970, bibliogr.; H about 1 1 d and with k K. and. Wolf D. Herzschall — Fibel, Einfuh-rung in die Mechanokardiographie, Stuttgart, 1962; L a n d o i s L. Graphische Untersuchungen liber den Herzschlag im normalen und Krankhaften zustande, B., 1876; Marey E.J.La of m£thode graphique dans les sciences exp6rimentales et particu-lifcrement en physiologie et en m6dicine, P., 1878; Rosa L. M. Einfuhrung in die ballistische Kardiographie, Munster, 1958, Bibliogr.

V. L. Karpman, A. V. Trubetskoy.

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