Blood Pressure in Assessment of Relative Intensity of the First and Second Heart Sounds

The integrity of the left ventricular function has a significant bearing on the intensity of the Ml component of the S1 (see Chapter 6). When S1 and S2 are not loud enough to be palpable, the assessment of their intensity must take into account the measured blood pressure of the patient. Extracardiac attenuating factors can lead to attenuations of the heart sounds. Because the degree of attenuation in any given patient will be expected to be similar on both S1 and S2, the intensity of S1 can be assessed only when compared to the intensity of the S2. The intensity or the loudness of the A2 component of the S2 is dependent to a large extent on the peripheral resistance, which is reflected in the diastolic blood pressure. A normal blood pressure would be expected to be associated with a normal intensity of A2, a high blood pressure would be expected to cause a loud A2, and finally a low blood pressure would be associated with a soft A2. The A2 intensity can be graded according to the blood pressure as probably normal, soft, or loud. Then if the intensity of the M1 is compared to that of A2, one can judge its relative intensity. It can then be graded as normal, soft, or loud depending on whether its intensity is equal to that of the A2, softer than A2, or louder than A2. While this exercise has some merit, its clinical value in the detection of left ventricular dysfunction is not established. Our preliminary observations suggest that the perception of the relative loudness of the M1 vs the A2 seems to be also influenced by the higher-frequency content of the A2.

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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