Question

To calculate the stroke volume (SV) and ejection fraction (EF) of the heart, you can use the following formulas:

1. **Stroke Volume (SV):** SV is the difference between the end-diastolic volume (EDV) and end-systolic volume (ESV).

SV = EDV - ESV
SV = 130 mL - 50 mL = 80 mL

2. **Ejection Fraction (EF):** EF is the fraction of the EDV that is ejected during systole and is calculated as the SV divided by the EDV, expressed as a percentage.

EF = (SV / EDV) * 100
EF = (80 mL / 130 mL) * 100 ≈ 61.54%

So, the stroke volume is 80 mL, and the ejection fraction is approximately 61.54%.

Answer 1

Stroke volume (SV) is the amount of blood pumped by the heart per beat and ejection fraction (EF) is the percentage of end-diastolic volume (EDV) ejected each beat. SV is calculated by subtracting the end-systolic volume (ESV) from EDV, while EF is the SV divided by EDV. These measurements are critical for assessing cardiac function.

Step-by-step explanation:

To accurately assess cardiac function, we commonly measure the stroke volume (SV) and ejection fraction (EF). SV indicates the amount of blood pumped by the heart with each beat and is calculated by subtracting the end-systolic volume (ESV) from the end-diastolic volume (EDV), with a typical resting SV in the range of 55-100 mL. To calculate the EF, which is the percentage of EDV ejected with each heartbeat, SV is divided by EDV. Normal EF ranges from approximately 55-70%, with a mean around 58%.

Ejection fraction is an important measure and is a reflection of several factors, including preload, contractility, and afterload. Measurements like SV and EF help clinicians evaluate cardiac health and function. Notably, these cardiac indices can be influenced by physical condition, heart size, sex, and the intrinsic properties of the myocardium itself.