## Monday, June 9, 2008

### Mathematical Relationships

Stroke Volume (SV): Volume of blood being pumped by a ventricle in one contraction.
-Example: 70 ml
Heart Rate (HR)
The heart rate is the number of contractions (heart beats) in one minute. Two common ways of determining this are by placing two fingers on your wrist (radial artery), or on your neck (carotid artery).
-Example: 80 beats per minute (bpm)
Cardiac Output:
The cardiac output is the volume of blood being pumped by a ventricle in one minute. Logically, you can find this by multiplying how much blood is pumped in one contraction, by how many contractions there are in one minute.
-Stroke Volume multiplied by Heart Rate
-Example: 70 ml(SV) x 80 bpm(HR) = 5600 ml/minute
Systolic Pressure: Pressure of blood in artery when the heart contracts
-Example: 123 mm
Diastolic Pressure: Pressure of blood in artery while the heart relaxes in between beats
-Example: 81 mm
A systolic pressure of 123 mm and a diastolic pressure of 81 mm would give a blood pressure of 123/81 (systolic over diastolic) This is read as “123 over 81.”