The hemodynamics of advanced heart failure are quite complex. In this post, I present a visual demonstration of some of these changes by looking at the carotid artery spectral Doppler waveform in advanced heart failure.
To begin let’s look at normal. The brain maintains a continuous supply of blood throughout the cardiac cycle. Thus, there is forward flow through systole and diastole in the carotid arteries. The spectral waveforms in the image below show this well. The brain does this by maintaining a low vascular resistance. Just like water finding the easiest path down hill, blood finds the easiest path to follow in the body. The brain makes it very easy for blood to flow into it; probably because it considers itself a vital organ.
In sharp contrast to normal shown above, in advanced heart failure we can see a reversal of flow immediately after systole that is striking in appearance if you are accustomed to the normal waveforms.
So, why do we see this waveform in advanced heart failure? Frankly, I don’t know for sure. I suspect it is a combination of effects including increased vascular stiffness and aortic valve dysfunction in dilated cardiomyopathy. Regardless, it is a good visual example of the altered hemodynamics of heart failure. I welcome your thoughts and ideas.