Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be

talking to you about cardiovascular support. And you can find written notes on this topic at

zero to finals.com slash cardiovascular support

or in the anesthetics and ICU section of the zero definals surgery book.

So let's get straight into it.

Let's start by talking about cardiac function.

The overall cardiac function or cardiac output is the result of a combination of

four things. Preload, after load, contractility and heart rate. Preload is the amount that the

heart muscle is stretched when filled with blood just before a contraction.

You can think of preload as the load or the stretch in the ventricle pre-contraction.

It's related to the volume of blood in the ventricle at the end of diastole, just before the ventricle contracts.

Afterload is the resistance that the heart must overcome

in order to eject blood from the left ventricle,

through the aortic valve and into the aorta.

You can think of afterload as being the load

or the resistance after the aortic valve,

how much resistance there is to pushing blood through the aortic valve.

Common causes of a raised afterload are hypertension and aortic stenosis.

Contractility refers to the strength of the heart muscle contraction.

Heart rate is the number of heartbeats per minute.

Systemic vascular resistance is the resistance in the systemic circulation

that the heart must overcome in order to pump blood around the body.

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