Auscultation continues being the traditional method and the first basic tool that is applied for the evaluation of the functional heart state. But, what is really what the doctor analyzes on auscultation? How does the phonocardiogram help in the diagnosis of the patient?
A Phonocardiogram (PCG) is a graphic record in the form of a wave in which you can see the heart sounds obtained with a stethoscope.
Thanks to the eKuore Pro digital stethoscope, not only can we hear the sound of auscultation, but we can also capture, record, measure and graphically represent auscultation in what we call phonocardiogram.
Which data does the phonocardiogram provide?
The phonocardiogram allows to provide data on the timing, relative intensity, frequency, quality, tone, timbre and precise location of the different components of the cardiac sound, in an objective and repeatable manner. In this way, the specialist can identify and analyze the sounds that make up the heart sound separately to later make a synthesis of the characteristics that have been extracted.
Which signal does a PCG record?
The sound that is collected in a PCG is given by the vibration that the heart performs during its cardiac cycle. This vibration is what produces the acoustic wave that is propagated through the chest wall.
The heart rate is the main component of the acoustic wave, but also each part of the heart itself has a particular constitution with its own biomechanical characteristics: natural frequencies, elasticity, damping and mechanical and acoustic impedances.
This means that both the vibration of the heart and the acoustic wave it produces, cover a wide spectrum of frequencies, which can range from 1 Hz or less, to over 1500 Hz. The amplitude of the acoustic signal is around 80 dB.
In the auscultation of the normal heart we mainly discover two noises: the S1 (“dumb”), which is a wide vibration that is due to the movement of the blood during the ventricular systole, to the closing of the mitral and tricuspid valves and to the posterior opening of the pulmonary and aortic valves; and S2 (“tub”) that is due to the deceleration and reverse flow of blood in the aorta and pulmonary artery, by closure of the aorta and pulmonary arteries and opening of the tricuspid and mitral arteries. This sound is shorter and more acute, and coincides with the end of the T wave.
The systolic separation of both noises is usually about two thirds of their diastolic separation. The heart sounds and murmurs are due to vibrations produced by acceleration or deceleration of the blood according to various theories.
How to register an FCG
To obtain a phonocardiogram you need a transducer that transforms the acoustic wave into a proportional electrical signal.
The instrument used classically to capture heart sounds is the stethoscope, which aims to transmit heart sounds with the least possible distortion and loss of amplitude.
EKuore Pro is the first electronic stethoscope on the market:
The emitter consists of a bell that is located in the thoracic part where it is located in the heart. By WiFi technology the signal is recorded in the receiver that previously has been connected to a mobile device. Through a simple application installed on the smartphone or tablet you can see the phonocardiogram that can be recorded, shared and reproduced later for future analysis.
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