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Re:25-year-old lived for more than a year without a heart by cushychicken on Wednesday June 08, 2016 @01:04AM (#11860142)
Wow, I had no idea you have no pulse when you have an LVAD. That's really neat.

Do you have any idea if there have ever been studies on the effect of constant flow vs peristaltic flow on the circulatory system? I wonder if the constant flow creates or solves any issues.

Re:25-year-old lived for more than a year without a heart by peff on Wednesday June 08, 2016 @01:40AM (#11860255)
That continuous flow is new(-ish). My father had an LVAD in 2002, and it was the older type that actually pumps rhythmically, so that was his pulse. At the time continuous-flow models were in research, and I do remember there were concerns with thrombosis (basically, the shifting force of the pulse helps break up clots).

I don't know the current state of the art, but there are definitely studies (the keyword is "pulsatile"). For example:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4250555/

For comparison, here's a picture of some LVADs. The one I've seen in person (after it had been taken back out!) is the one on the far left. Flow issues aside, I can imagine the smaller ones are easier on the patient in general, just from the perspective of surgery trauma.

http://reliantheart.com/wp-content/uploads/2013/04/VAD_Size_...

Re:25-year-old lived for more than a year without a heart by forgotpwagain on Wednesday June 08, 2016 @10:58AM (#11862651)
To elaborate a little bit more: the first generation of LVADs were had large mechanical pumps and were huge -- they could only be implanted in people with a large chest cavity, excluding a large number of patients (especially women) from eligibility for their device.

Current popular models are continuous flow rotors that are much smaller (enabling their use in almost anyone) and are non-pulsatile.

However, there's been a big push to move towards pulsatile devices. This is mostly driven by mechanobiolgy studies that show that there is a difference in the cellular programs of cells that are exposed to a continuous shear force versus a pulsatile shear force. Accordingly, to more closely replicate the natural physiology of the heart, there has been a big push towards using pulsatile devices.

Re:25-year-old lived for more than a year without a heart by dogma1138 on Wednesday June 08, 2016 @06:08AM (#11861173)
There is a difference between pulse and heartbeat, the pulse is from the veins and you can feel it even with an LVAD.

The audible heartbeat is from the heart sliding in the pericardium sac when it beats, many people lose the audible heartbeat after having heart surgery when the pericardium sac has to be cut or removed completely e.g. if someone is having a bypass surgery.

Re:25-year-old lived for more than a year without a heart by naveen99 on Wednesday June 08, 2016 @08:26AM (#11861720)
Peripheral Veins are not pulsatile (near the heart, they have a complicated waveform). Peripheral pulse is arterial.
Re:25-year-old lived for more than a year without a heart by jeroen on Wednesday June 08, 2016 @09:34AM (#11862149)
The audible heartbeat is from the valves closing.
Re:25-year-old lived for more than a year without a heart by et2o on Wednesday June 08, 2016 @10:33AM (#11862509)
Yeah! Maybe the OP has the heart sounds confused with a pericardial friction rub, which can happen in pathological states and is due to the heart sliding against the pericardium.
Re:25-year-old lived for more than a year without a heart by cushychicken on Wednesday June 08, 2016 @02:56PM (#11864648)
I didn't know there was a difference in terminology when I asked. This was a worthwhile question - I learned a lot.

Thanks for the great explanations!

Re:25-year-old lived for more than a year without a heart by davycro on Wednesday June 08, 2016 @05:46AM (#11861092)
How do you perform CPR on a person with an LVAD? Plug the device in.
Re:25-year-old lived for more than a year without a heart by davycro on Wednesday June 08, 2016 @08:24AM (#11861700)
I'm not being snarky. I saw several patients with LVADs on my cardiology rotation in medical school. As far as I know they are the only patients exempt from CPR if they have a cardiac arrest, although device failure should be the only reason for this.