Understanding cardiac physiology – the Starling curve.

starling curve 001

pictured above – the inset boxes in the bottom portion of cardiovascular decompensation and

cardiac dysmorphia are representations of the RV and LV startling curves.

The green dots on these starling curves represent the “Goldilcoks” zones.

The red dots represent their location in their current state of cardiac dysmorphia.

starling curve 005

We will get to the point in our discussion where we will understand how CPR may actually

get us back in the “Goldilocks” zone.

starling curve 007

This Starling curve is where we all currently exist.

If you gave 1L (one liter) of NSS fluid challenge, the cardiac output would increase by a given amount.

starling curve 009

If you were on a “booze cruise” in the sunny isles, between alcohol exerting its diuretic effects and

dehydration in the hot, hazy atmosphere, your status on the Starling curve would shift rightward.

In this case, a 1L NSS intravenous fluid (IVF) challenge,  your cardiac output would increase by a

significant amount.

This is because the sarcomeres were understretched and after 1L of extra IVF in your vascular

system, the cardiac output generated by a then underfilled LV and now properly filled (and in the

Goldilocks zone) will give you great “bang for the buck” (great cardiac output).

starling curve 008

In the case of heart being overfilled and being challenged by 1L of IVF, the heart will

further exacerbate itself and result in further deterioration of cardiac function.

In this case the sarcomeres would go from overstretched to severely overstretched

and essentially become useless with cardiac failure not far in its future.

starling curve 010

The Starling curve is represented with the aforementioned three scenarios of

(from left to right on the curve) understretched, to “just right” to overstretched

sarcomeres (as represented on the bottom of each graph).

Just imagine a shock absorber in its place.

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