PULSE WAVEFORM

“The heart is a tough organ: a marvelous mechanism that, mostly without repairs, will give valiant pumping service up to a hundred years.” ~ Willis John Potts MD. American Surgeon, 1895-1968

In the ageing process we discussed pulse waves and wave reflections.

On the right we can see the pulse wave from the heart of a healthy 25 year old. These waveforms provide an assessment of cardiovascular health and arterial stiffness. The heart beats and we have the systolic pressure measured initially (graph 2 red spike).

Don’t confuse the blood flow with the pulse wave.  In the first 3 grapns the blood flow is the same as the pulse wave. But, in the third graph, the blood has reached a “fork” in the artery and continues its path. We are interested in the reflected wave. Remember the image of dropping a pebble into a pond and the ripples that are created. When the ripples hit something solid then they bounce back. As part of measuring the condition of the artery, we follow the path of this ripple back towards the heart.

In our 25 year old, the pulse wave reaches the point (or approximately the point) of where the red spike (the systolic pressure) ends. The reflective wave forms a notch called a dicrotic notch (graph 5). This shows that the heart is able to rest between heart beats.

Unfortunately, we are not all healthy 25 year olds.

Below right is the pulse wave of an 82 year old.

The pulse wave form is very different from the 25 year old in the example above. Let’s explain why:

As the arteries are stiff, the speed, or velocity, of the reflected wave increases and the reflected wave is further to the left of the initial wave form created by the heart beat. This means that the heart starts its next beat before the reflected wave returns to the heart. When this happens, the heart must work harder to pump blood as part of its normal beat and to counteract the reflected wave. This puts added pressure on the heart and will create heart failure if not treated.