Category Archives: Medicine


My PhD and What Comes Next

If you’ve been following my Twitter or Facebook accounts, you’ll already know that I successfully defended my doctoral dissertation this past Wednesday. I now (essentially, absent the completion of some clerical things) have my PhD from Johns Hopkins University.

One thing that is asked a lot of people graduating from anything is what they plan to do next. I have been waiting for some time to be able to answer that question, and now I can.

The lab of which I have been a member since late fall of 2002, the Trayanova lab is one of (if not the) the leading groups in the world when it comes to cardiac electrophysiology and mechanics research. I would guess that the lab as a whole has probably run an order of magnitude more simulations, at a minimum, than the next closest group. A lot of my time and effort as a graduate student went into improvement of the tools used for generating and running models, and I have nearly seven years of experience setting up, running, and analyzing simulations.

The lab does very interesting things, and cutting-edge research. Almost every new study is accompanied by tool and methodological development. However, there are a lot of practical applications that are never explored by the lab, because they don’t necessarily constitute scientific discovery of the kind valued in academia.

It takes a long time to train people to use simulation software developed in an academic research environment. It is extremely powerful, and has far more options available than any one user will ever use. This is acceptable for graduate students that will be spending years in the lab, and will often be digging in the guts of the code and adding their own features. It’s not acceptable for, say, industrial or academic wet-lab researchers that just want to run some simulations and figure something out.

That’s where CardioSolv comes in. CardioSolv, LLC, is a new cardiac simulation and services company. Its aim is to commercialize cardiac simulation, and make it easy for new users to rapidly produce scientifically valid and useful results. To that end, we are building a web interface that will by default handle most of the difficult choices for users, while still allowing them to specify detailed parameters if necessary.

My role in this company is Vice President of Operations. I’ll be managing the day-to-day operations of the company, interacting with customers, and guiding product development. My hope is that we can bring our technology and our discoveries out of academia, and into the drug and device development markets, with the ultimate goal of improving patients’ safety and quality of life.

Old paper on pacemaker explosion

Check this out:

An 81-year-old woman with a mercury-zinc powered permanent pacemaker experienced the sudden pain on her pacemaker pocket followed by an explosion. We are aware of no other report of the spontaneous and symptomatic bursting of a generator battery with fracture of the pulse generator capsule.

Emphasis mine. It’s an old paper (1987) and you can get the full text for free at the journal’s site, here.

Crazy, huh?

How much energy is applied by a pacemaker?

I can’t find this information anywhere — how much energy is applied per pulse by a typical pacemaker? I’m sure it depends on lead implantation and so on, but there must be some reasonable range used for the design of the devices.

A related question I’m also having trouble answering is “what is the typical pain threshold for cardiac stimulation?”. Any pointers to answers are welcome. The fact that most of the (potentially) relevant papers are locked up and not indexed by Google is not helping.

Hearty Friday – Ott et al.

I have a special Hearty Friday for you today. Recently, there was a very cool paper published in Nature by some people at the University of Minnesota, Harvard, and several other institutions.

The HubMed page is here, the Nature Medicine page is here.

I plan to review this article at some point, but for now, here’s a picture of their recellularized scaffold. That is, they took an animal heart, washed all of the cells out, leaving the fibrous scaffold, and put cells back in, letting them grow back into a beating “heart”. This is snapped from Figure 4 of their paper.