hund_2004

History:

Received two Hund_Rudy_2004 model files from Penny, 08/2007. First was normal cell model, second was a model altered for tissue propagation.

Inquired as to whether tissue model was published. Received response from Penny as below.

Put model up but then removed it.

Curation Status:

Model runs in PCEnv and COR and produces expected, published output, needs documentation.

Response:

Hi James,

Here is the 'answer' I got concerning the Hund_Rudy model 'tissue'. Maybe for now we leave it as we don't know what is best?! OR I would go for 'HRd propagation'.

Thanks, Penny

-----Original Message----- Sent: 18 September 2007 14:47 To: Penny Noble Subject: Re: Hund_Rudy tissue model

Hi Penny,

Glad to hear you have coded up the Hund-Rudy models. As far as I know, the "tissue" version has not been published by them. However, they have it on their website:

http://rudylab.wustl.edu/research/cell/methodology/cellmodels/HRd/HRD%20on%20the%20web/HRD%20propagation%20simulation.htm

(If the link doesn't work, just google "hund-rudy model" and click the relevant link under "simulation notes.")

We also used these modifications in our most recent AJP paper, so they have been published there with a "personal communication" reference to Rudy.

It might be better to refer to it in some manner more reflective of how they call their link, "modifications to HRd code for simulation of propagation." Maybe it should be HR propagation instead of HR tissue? I kind of always thought they would hate it being called HR tissue, but at the time we were writing the paper it seemed the best way to refer to it, and we weren't sure there was any way to refer to it that would not upset them! So I'm not sure what is best there.

Elizabeth

Contents of Linked Website:

The original HRd formulation, without the changes below, was necessary to reproduce the experimental rate dependence of the L-type, of the AP notch (it decreases with increasing rate) and of the dome morphology in epicardial cells with a prominent notch and “spike and dome” morphology. Prior to the HRd model, no published canine models could reproduce this behavior, as well as the rate dependence of the calcium transient. In the tissue, cells do not exhibit such prominent notch and behave somewhat differently (due to many possible factors that are changed by cell isolation). With the adjustments below, the propagating AP model (upstroke, notch, APD, APD rate-dependence) closely matches experimental tissue data from the dog.

Important Note: These adjustments are intended for simulating conduction properties only, not dynamics of AP repolarization.

  1. The variable gNa in the formulation of the Na+ current is increased by a factor of 1.4
  2. The variable 'pow' (dynamic activation gate) in the formulation for the L-type is set to a constant value of 1
  3. The variable 'vg' (variable gain) in the formulation for calcium release is set to a constant value of 1