FS in the context of an echocardiogram (echo) refers to Fractional Shortening.
Understanding Fractional Shortening (FS)
Fractional Shortening (FS) is a measurement used in echocardiography to assess the systolic function of the left ventricle, the heart's main pumping chamber. It reflects the change in the left ventricle's diameter during contraction (systole) compared to its diameter during relaxation (diastole).
How FS is Measured:
- During an echocardiogram, the diameter of the left ventricle is measured at two points in the cardiac cycle:
- End-diastole: The point at which the left ventricle is most relaxed and filled with blood.
- End-systole: The point at which the left ventricle has contracted and squeezed out blood.
- The difference between these two measurements, expressed as a percentage of the end-diastolic diameter, gives the Fractional Shortening.
Formula for Fractional Shortening:
The formula for calculating FS is:
FS (%) = [(LVDd - LVDs) / LVDd] x 100Where:
- LVDd = Left ventricular internal dimension at end-diastole
- LVDs = Left ventricular internal dimension at end-systole
Significance of FS:
- FS provides a measure of the heart's pumping ability.
- A normal FS value generally indicates healthy left ventricular systolic function.
- Reduced FS can suggest decreased contractility of the left ventricle, which may be indicative of heart conditions.
Normal Values:
- Normal values for FS typically range between 25% and 45%.
- However, normal ranges can vary slightly depending on the laboratory and guidelines.
Other Measurements:
- According to the reference, assessment of left ventricular systolic function should also include measurements of ejection fraction (EF) and cardiac output (CO), in addition to FS. These measurements complement FS for a comprehensive view of cardiac function.
Table Summarizing FS
| Measurement | Definition | Significance | Normal Range |
|---|---|---|---|
| Fractional Shortening (FS) | Percentage change in left ventricular diameter during contraction. | Assesses systolic function of the left ventricle. | 25% - 45% |
In essence, FS is one of the tools used during an echocardiogram to assess the health and function of the heart, specifically the left ventricle's ability to pump blood effectively.
