Matters Of The Heart-Heart Sounds/BP Assessment

When you listen to the heart via a stethoscope you hear two distinct sounds infamously known as the 'Lub-Dub' (or if you wanna be all scientific, 'S1' and 'S2')

The First Sound in the cycle ('Lub'/'S1') is louder then the second. It is made by the closing of both of the Atrio-Ventricular Valves. They close after the ventricles have filled with blood and are about to be pumped out to their respective destinations.

There is a short period between the 'Lub' and the 'Dub'. During this time, the semilunear valves open and the ventricules are activelly pumping/pushing blood into pulmonary and systemic circulation: this time period is called Systole.

(When you take someone's blood pressure with a sphignomanometer, your aim is to achieve two numbers. The first indicates the amount of pressure the heart is pushing blood out during Ventricular Systole or ventricular contraction. This is called Systolic Blood Pressure)

The Second Sound ('Dub'/'S2') is slightly softer, and it is made by the semilunear valves closing after the ventricles have pumped blood through them.

Immediately after 'Dub'/'S2' sound, the heart is at 'rest' (the ventricles that provide cardiac output to pulmonary/systemic curculation are recieving blood, not pumping it.) This time period is known as Ventricular Diastole.

(Again, when you take someone's blood pressure with a sphignomanometer, your aim is to recieve two numbers, the second number is the amount of pressure in the systemic circulation when the heart is NOT pumping blood into them. This number is called Diastolic Blood Pressure.)

Sometimes other sounds--not consistant with the 'lub-dub' pattern--are heard when auscultating (listening for) heart sounds with a stethoscope. At times this is because the valves are not closing simultaneously (resulting in 'Split' heart sounds), or there is turbulent blood flow (resulting in a 'heart murmur')

Blood Pressure Readings

Typically when the Atria are contracting (atrial systole) the Ventricles are relaxing (ventricular diastole). When we check the blood pressure on a patient, we are measuring left ventricular systole and diastole (Because it reflects the amount of blood being pumped out of the heart and towards the rest of the body).

Blood pressure readings will vary depending on the individual patient's normal values. Commonly recognized 'Normal' blood pressure readings are 120/80, (or '120 systolic over 80 diastolic') Blood pressure is measured in millimeters of mercury (abbreviated as mmHG).

Hypertension-

A blood pressure reading equal to or greater than 140 systolic and/or 90 diastolic is often considered too high. Prolonged hypertension causes damage to blood vessels; increasing risk for hypoxia, infarct, and aneurysm.

Hypotension-

A blood pressure reading of less then 90 systolic and/or 60 diastolic is often considered too low. Hypotension often displays more acute signs and symptoms-such as fatigue, weakness, dizziness (esspecially with position changes), poor urine output/renal failure, and altered level of consiousness.