Normal Stroke Volume (Plus The 3 Things That Affect Stroke Volume)
Echocardiography is a world of measurements. Just think for a moment about your standard echo protocol. Think about how many times your hands reach for the calipers to make a measurement. Whether we’re measuring a spectral Doppler tracing of the LVOT VTI, 2D measurement of the left ventricular wall thickness or 3D volume…we do a ton of measuring.
There’s one thing as a cardiac sonographer that we really need to know. And that is the normal values of all the many different things that we’re measuring.
In this post, we’re going to touch on what the normal values are for stroke volume and stroke volume index.
What Is Left Ventricular Stroke Volume?
Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction, or with each beat. As you probably already know, only about two-thirds of the blood in the left ventricle is pumped out with each beat.
To learn more about how to obtain accurate left ventricular stroke volume measurements using echocardiography, read my post, How To Calculate Stroke Volume In Echocardiography (The EASY Way).
What’s A Normal Stroke Volume Value?
Normal stroke volume in a healthy adult can be anywhere between 60ml and 120ml. Granted there are many things that can affect stroke volume, such as exercise and heart rate, but in general, a normal stroke volume for a healthy person will fall between these values.
What Affects Stroke Volume?
There are 3 things that affect stroke volume. Those things are:
Preload: The filling pressure of the heart at the end of diastole.
Contractility: The inherent vigor of contraction of the heart muscles during systole.
Afterload: The pressure against which the heart must work to eject blood during systole.
What Is Stroke Volume Index
Stroke volume index is when you take the stroke volume as measured in ml’s and divide it by a a person’s body surface area, or BSA. By using stroke volume index, you can easily compare your SV with someone else’s SV who has a completely different body type. Stroke volume index also allows direct comparison of large and small patients.
Normal Stroke Volume Index
A normal stroke volume index in a healthy adult can be anywhere between 35 ml/m2 and 65 ml/m2 .
Normal stroke volume is dynamic and is not a single number. Rather, a normal stroke volume will fall within a “normal” range of 60ml and 120ml. And the three main things that affect stroke volume are Preload, contractility and afterload.
I you’re new to echocardiography, or just have any questions regarding what it’s like to be a cardiac sonographer, don’t hesitate to reach out!