The "heart formula" can refer to a few different concepts in cardiology, depending on the context. Below are some key formulas related to heart function:
1. Cardiac Output (CO)
Cardiac output is the amount of blood the heart pumps per minute, and it’s a key indicator of heart function.
CO=HR×SV
Where:
CO = Cardiac Output (mL/min or L/min)
HR = Heart Rate (beats per minute)
SV = Stroke Volume (mL/beat)
2. Stroke Volume (SV)
Stroke volume is the amount of blood pumped by the left ventricle in one contraction.
SV=EDV−ESV
Where:
EDV = End-Diastolic Volume (the volume of blood in the ventricle at the end of diastole)
ESV = End-Systolic Volume (the volume of blood left in the ventricle after systole
3. Ejection Fraction (EF)
Ejection fraction is the percentage of blood pumped out of the ventricle with each contraction, used to assess the heart's pumping efficiency.
EF=SV/EDV×100
Where:
EF = Ejection Fraction (percentage)
SV = Stroke Volume
EDV = End-Diastolic Volume
4. Blood Pressure (BP)
Blood pressure is the force of blood against the walls of arteries, typically measured as systolic over diastolic pressure.
BP=CO×SVR
Where:
BP = Blood Pressure (mmHg)
CO = Cardiac Output (L/min)
SVR = Systemic Vascular Resistance (mmHg·min/L)
5. Mean Arterial Pressure (MAP)
The mean arterial pressure is the average pressure in a patient's arteries during one cardiac cycle. It is an important determinant of tissue perfusion.
MAP=DBP+1/3(SBP−DBP
Where:
MAP = Mean Arterial Pressure (mmHg)
SBP = Systolic Blood Pressure (mmHg)
DBP = Diastolic Blood Pressure (mmHg)
6. Cardiac Work
Cardiac work is the amount of energy the heart expends to pump blood, and it's typically calculated using the pressure-volume relationship.
Cardiac Work=SV×MAP
Where:
SV = Stroke Volume (mL/beat)
MAP = Mean Arterial Pressure (mmHg)
7. Heart Rate (HR)
Heart rate is the number of beats per minute. It can be influenced by factors such as exercise, stress, and heart conditions.
HR=60/RR Interval (in seconds)