PHONOCARDIOGRAPHY

From Big Medical Encyclopedia

FONOKARDIOGRAFYYa (Greek phone a voice, a sound + kardia heart + grapho to write, represent) — registration of the sounds resulting from action of the heart; it is applied to assessment of action of the heart and diagnosis of its disturbances.

The first record of sound phenomena of heart is carried out in 1892 Mr. of Gyurtle (To. W. Hurtle), however implementation F. in a wedge, practice 20 century when microphones were improved became possible only in the 40th and the frequency filters which provided a possibility of comparison of the registered phenomena with data of auscultation began to be used. (see), at a cut not all sounds accompanying action of the heart are perceived (because of small sensitivity of the acoustic analyzer of the person to fluctuations of low frequency).

T., carried out by modern diagnostic units, objektivizirut these auscultations of heart in the form of the phonocardiogram (FKG) displaying emergence and the termination of cardiac sounds (see) and noise of heart (see Noise cordial) on time in the form of the periodic, divided by certain intervals fluctuations, to-rye can be quantitatively characterized on frequency structure and amplitude (see the Sound). Registration of FKG in different frequency

pazona of a di is sufficient for approximate frequency analysis of tones and noise of heart (on different frequency channels of the registrar). The exact frequency characteristic of these phenomena can be received with pokhmoshchyyu special spectral F. Cardiac sounds have more low frequency, than noise, and amplitude of fluctuations of tones is much higher. In diagnostic testings apply the table offered Schmidt-Foygty to their frequency assessment

(J. Schmidt-Voigt, 1955), according to a cut the prevailing frequency of fluctuations makes for 1 cardiac sound 30 — 120 Hz, for the II tone — 70 — 150 Hz, for systolic noise — 50 — 600 Hz, for diastolic — 120 — 800 Hz.

As well as auscultation, T. has important diagnostic value, first of all for diagnosis of valve heart diseases (see Heart diseases inborn, the Heart diseases acquired). The objective quantitative characteristic of the studied sounds and intervals between cardiac sounds received by means of F., significantly expands possibilities of use F. as method of functional diagnosis (see). It is widely used, in particular, for the phase analysis of cordial activity (see the Poly-cardiography) and finds application for assessment of sokratitelny function of a myocardium in option so-called for the selection, or selective (local), T., allowing to register sounds of heart from a certain point.

Registration of FKG is made in in specially equipped isolated room where it is possible to create complete silence. Temperature indoors shall be not lower than 18 — 19 °. Before registration the doctor defines points on a thorax by auscultation of heart, with to-rykh then record is made. Position of the patient during F. horizontal, weakened. FKG register synchronously with an ECG (in standard or one of single-pole assignments from extremities). For registration of FKG for a thorax of inspected install the microphone — consistently in 5 — 7 chosen points in heart, including in the field of a top, in Botkin's point, over valves of an aorta and a pulmonary trunk (see Noise cordial). Correctness of settings of the microphone is controlled aurally by means of phone or a loudspeaker. Record is made consistently in all points at breath holding on an exhalation in 6 frequency ranges, from to-rykh

1 — low-frequency, 2 — mid-frequency, 2 — high-frequency and 1 — broadband (auskultativny). In some cases with the diagnostic purpose of FKG register before and after an exercise stress or pharmacological test.

The analysis of normal FKG constantly reveals existence of I and II cardiac sounds; with smaller constancy III, IV and other tones (see Cardiac sounds) arising in a diastole are registered. During the definition of character of cardiac sounds consider time of their emergence, amplitude, duration and frequency structure. Intervals between cardiac sounds at the known heart rate in each age group have certain limits of values and normal shall not go beyond their limits. The interval between I and

II tones (a phase of a systole) over a top of heart averages 0,28 — 0,32 sec. at normal number of cordial reductions (75 — 80 in 1 min.). The interval between II and the III tone over a top of heart at people is more senior than 10 years 0,15 sec., over the basis — 0,18 sec. average. The interval between III and

the IV tone depends on duration of a diastole of ventricles. If the diastole short (at tachycardia), it can disappear, then the merged III and IV tones (so-called summatsionny tone) are registered. The interval between the beginning of IV and the beginning of the I tones over a top and the basis of heart averages 0,058 — 0,06 sec. Measurement of intervals between cardiac sounds on FKG and separate elements of synchronously registered ECG allows to make the profound phase analysis of a systole of a left ventricle of heart.

Noise of heart are shown on FKG by oscillations with a frequency from 50 to 1000 Hz.

On FKG perhaps accurate distinguishing of noise on a phase of a cardial cycle (systolic or diastolic); it is quite often possible to judge also their functional or organic nature. Functional noise more often are systolic; they are registered, as a rule, in the form of oscillations of low and average frequency (from 50 to 200 Hz), low amplitude, and differ in variability on intensity, duration and a form in different cardial cycles. Organic systolic noise is presented on FKG by constants in all cardial cycles high-frequency and mid-frequency oscillations. The form of noise can be various: the extending I cordial tone fading, continuous, uneven, accruing to the II tone, «rhomboid», «tape-like», etc. that depends on a type of defeat of the valve and muscular device of heart.

Organic diastolic noise is registered on FKG, as a rule, high-frequency low-amplitude oscillations. Distinguish several types of diastolic noise depending on time of their emergence: protodiastolic (at the beginning of a diastole), mesodiastolic (in the middle of a diastole) and in the last phase of a diastole — presystolic. Also continuous diastolic noise is possible. At F. distinguish the ichesky noise which are also mixed systoles about-diasto l i.e. registered throughout a systole and a diastole. Frequency of fluctuations at such noise and their amplitude are extremely changeable; tones at the same time can not be differentiated or come to light with great difficulty at all.

Use F. for dynamic overseeing by a condition of the patient increases reliability of diagnostic inferences and gives the chance to estimate efficiency of treatment.

The phonocardiography at children is applied with the same purposes, as at adults. Feature of the technology of registration of FKG at children to 3 - years - it age is simultaneous record of respiratory noise. At more senior children at performance by the child of the team «not breathe» F. it is made after an exhalation with the maximum relaxation of all muscles.

For registration of FKG the microphone is installed consistently, as well as at adults, on standard points — in the fifth mezhreberye under a nipple (a top of heart), in the fourth and second mezhreberye at a breast, in the second mezhreberye at a breast, according to indications also in axillary area at the level of a nipple at the left on the right at the left at the left and in points where at auscultation noise and additional sounds are defined. FKG at children differs in bigger detailing of components because of thinner wall of a thorax, but in connection with the heart rate, bigger at children, it is necessary to register FKG for simplification of its interpretation at the movement of a tape with a speed of 100 mm! sec.

At rather high sensitivity of the chart recorder on FKG at healthy children it is possible to distinguish four fiziol. cardiac sound and systolic noise. Initial fluctuations of the I cardiac sound are registered in 0,02 — 0,04 sec. from the beginning of a tooth of Q on an ECG, have small amplitude and quickly (approximately in 0,01 sec.) pass into the maximum, corresponding to a tooth S to an ECG. Duration of these fluctuations makes apprx. 0,05 sec. Then the second group of fluctuations of smaller amplitude — the so-called systolic tone of tension of atrioventricular valves corresponding on time approximately to the middle of a segment of ST on an ECG is allocated. The general duration of the I tone is equal 0,07 — 0,15 sec. (more often 0,08 — 0,12 sec.), and the interval from the beginning of a tooth of Q on an ECG before the first maximum fluctuations of the I tone (Q — the I tone) does not exceed 0,07 sec. Amplitude of the maximum fluctuations of the I cardiac sound varies depending on a place of registration, but on a top of heart usually exceeds or is equal to amplitude

of the II tone; it considerably decreases at delay of atrioventricular conductivity.

Initial fluctuations of the II cardiac sound of small amplitude appear on average in 0,02 sec. from the termination of a tooth of T on an ECG and approximately in 0,01 sec. turn into the maximum high-frequency fluctuations from closing of semi-lunar shutters of the aortal valve. Then in 0,02 — 0,04 sec. the pulmonary component II of tone is registered. In the low-frequency range (12 — 25 Hz) the second sound of tension of atrioventricular valves (so-called click of opening of the mitral valve) in the form of one fluctuation approximately in 0,07 sec. from the beginning of the II tone can be registered. The general duration of the II tone makes from 0,04 to 0,12 sec., discrepancy of components II of tone among themselves within its duration has no essential value. Amplitude of the II cardiac sound and its components varies depending on a place of registration, it is most expressed on FKG registered over a pulmonary trunk.

In 0,13 sec. (on average) from the beginning of the II tone or at the end of the first third of a diastole, i.e. at the time of the termination of relaxation of ventricles, on a top in the ranges of low frequencies the III cardiac sound is registered. Than the tone of a myocardium is lower, especially the III cardiac sound is expressed. On FKG it is presented by one or two fluctuations lasting 0,02 — 0,03 sec., amplitude makes it near x / 4 amplitudes of the I tone in the same range.

In 0,06 — 0,12 sec. from the beginning of a tooth P on an ECG

the IV cardiac sound in the form of one-two fluctuations of low frequency and small amplitude is registered. Normal duration makes it apprx. 0,03 sec., and amplitude — apprx. x/t parts of amplitude of the I tone in the same frequency range. The isolated IV cardiac sound is registered during the lengthening of an interval P — Q, and at tachycardia is followed by the additional fluctuations of low frequency imitating presystolic noise. The sound of the IV cardiac sound is registered on the basis of heart better and is transferred to area of a top.

For the characteristic of intensity III and IV cardiac sounds the amplitude index, i.e. the relation of amplitude III or IV tones to amplitude of the I tone in the range of 50 — 75 Hz is defined. This indicator fluctuates within 0,187 — 0,262 for the III tone and 0,066 — 0,123 — for the IV tone.

At children often register fiziol. systolic noise of emission of blood; it is isolated from I and II cardiac sounds, has the spindle-shaped form, small amplitude, is better expressed in the fourth and second mezhreberye at a breast at the left. Differential and diagnostic value have an interval from the beginning of a tooth of Q on an ECG before the maximum fluctuations of this noise and its relation to an interval of Q — T on an ECG, expressed as a percentage that is designated as an index of time of the maximum fluctuations of systolic noise. At healthy children this index is equal

to 53 — 56% •

At certain healthy children fluctuations in a mesodiastole — after the III tone and only in the low-frequency range (functional mesodiastolic noise) can be registered. The age of the child is less, the with a bigger frequency the FKG low-frequency components are registered, to-rye almost are not perceived at auscultation.

Children with heart diseases have amplitude of tones, intervals between them, and also between tones and the ECG separate elements change according to the nature of pathology; there are patol, tones and noise. The analysis of these changes has important diagnostic value, especially at heart diseases. At disturbance of exchange processes in a myocardium there is a reduction of an interval of the I—II tone (mechanical systole). In this regard the relation of a mechanical systole of heart to electric, expressed as a percentage, decreases (a sign so-called ener-getyacheski-dinamicheskoi insufficiency of heart).

Phonocardiographs — the devices intended for registration of FKG in diagnostically significant frequency ranges. The phonocardiograph consists of the microphone, the amplifier, frequency filters and the graphic registrar.

The microphone is the perceiving device and at the same time the converter of the sound vibrations of heart perceived from the surface of a thorax of the patient in an electric signal. Microphones for F. subdivide on contact and with an air chamber; in the latter case sound vibrations from the surface of a thorax are transferred to a sensitive element of the microphone through the air environment. Advantage of the contact microphone is its lower sensitivity to noise indoors where the research, and smaller dependence of the received records on quality of a prileganiye of the microphone to a chest wall is conducted.

Amplifiers in modern phonocardiographs combine with filters, the basic purpose to-rykh consists in suppression of the low-frequency fluctuations which are not heard at auscultation. Apply as the high-frequency filters lowering sensitivity only to low-frequency components, and strip, providing record of cordial sounds in the certain frequency range of a sound range.

Chart recorder F. shall provide record of sound vibrations with frequencies up to 800 — 4000 Hz. To such devices photo recorders and registrars treat with jet ink record. So-called record with transformation was widely adopted, edges it is made on chernn lnopishushchy registrars of the same type, as for registration of an ECG, by way of modulation on amplitude the signals allocated with filters, signals of the auxiliary generator with a frequency of 80 — 100 Hz. In this case the received record of frequency of the auxiliary generator keeps all amplitude and temporary ratios of signals at the exit of filters.

The domestic industry produces the FKG-01 phonocardiograph in lots. It provides record on chernilnopishushchy registrar of FKG, and also ECG, sphygmogram and phlebogram, i.e. can be applied for polikard yografiya (see).

The phonocardiograph contains the MF-1 microphone, the block of amplifiers and filters and high-speed four-channel registrar N-338-4. The MF-1 microphone of electrodynamic type with an air chamber has frequency range from 10 to 2000 Hz and can be used both to record FKG, and to absolute measurements of sound pressure. Distinctiveness of the phonocardiograph is the possibility of use of two types of filters — for the so-called filtered phonocardiography across Maas and Weber, edges are provided by record FKG in 6 frequency ranges, and strip filters.


The registrar H-338-4 ooze provides record of signals with a frequency no more than 100 — 120 Hz; in the phonocardiograph transformation of phonocardiographic signals is applied.

Serially released converter phonocardiographic universal PFU-01 is intended for registration of FKG on ordinary electrocardiographs. It contains the MF-1 microphone, the three-channel amplifier with filters, a two-channel oscilloscope for observation of signals FKG and the device for record FKG by method of transformation. The available program switch of filters provides the standard sequence of their inclusion.

Bibliography: Zelenin V. F. Kardio-

phonography (registration of cordial tones and noise) and its clinical value, M., 1915; Kassirsky G. I. and Solovyov V. V. Atlas of a clinical phonocardiography, M., 1983; To at z N e c about in A. I. Znacheniye of some components of the phonocardiogram in diagnosis of changes in heart at children, Pediatrics, No. I, page 58, 1971; Oskolkova M. K. Functional diagnosis of heart diseases at children, M., 1967; F and t and l e in and L. M. Clinical phonocardiography, M., 1968; Functional diagnosis at children's age, under the editorship of S. Komarov and V. Gatev, lane with bolg., Sofia, 1979; X about l l d and to To. and Wolf D. The atlas and the guide to a phonocardiography, the lane with it., M., 1964; Avila J. E. at. lake of Estudio fonomecanocardiografico de los soplos inocentes en ninos, Arch. Inst. Cardiol. Mex., v. 52, p. 103, 1982; K u 1 a n-g a r a R. J., Strong W. B. a. Miller M. D. Evaluation of heart sounds and murmurs in children, Postgrad. Med., v. 72, p. 156, 1982; Schmidt-Voigt J. Atlas der klinischen Phono-kardiographie, Miinchen — B., 1955; Stapleton J. F. a. Harvey W. P. Systolic sounds, Amer. Heart J., v. 91, p. 383, 1976; Wink K. Phonokardio-graphie heute? Diagnostik, Bd 15, S. 697, 1982.

L. M. Fitileva; V. M. Bolshov (tekhn.),

A. I. Kuznetsov (ped.).

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