As we have discussed before, the heart's job is to generate pressure. Blood pressure in the heart is expressed with 2 numbers: a top number, and a bottom number. If the doctor tells you your blood pressure is 120 over 70, the top number stands for the highest number acheived in the heart when it is contracting (systolic). The lower number is the pressure in the heart when it is relaxing (diastolic). Every part of the heart as it generates pressure has its own unique wave of pressure related to its location in the heart pumping cycle.

The pressures in the heart start with low pressure in the Right Atrium to higher pressure in the right Ventricle which pumps the blood to the lungs, to lower pressure again in the Left Atrium, and then very high pressure in the Right Ventricle which pumps the blood to the body.

Please look at the diagram to see how pressure in the Right Atrium is making a low pressure wave while the pressure in the Right Ventricle is making a high pressure wave. Notice that the Left Ventricle is making the highest pressure wave.