Part of my exam asks about leads. This has brought something to my attention: I don’t really know much about ICD leads. I’ve seen them, held them, I know that they have different numbers of electrodes and different ways of staying put, and I’ve seen them implanted, but now I’m going to have to learn a lot more about their functions, constructions, and applications.
Category Archives: Medicine
Qualifier Phase 1: Online Research
I’m guessing if I turned in an open-book qualifier response based entirely on about.com and wikipedia I’d probably fail, but I think these sorts of sites have an important role in the research: somewhere to start from. I’m using Freemind to organize what I find.
I’ve begun by searching wikipedia (found nothing) and then moved rapidly straight to Google, where I found a few appropriate results:
What is Cardiac Resynchronization Therapy? | Medtronic Cardiology
Cardiac resynchronization therapy (CRT) is a proven treatment for selected patients with heart failure-induced conduction disturbances and ventricular dyssynchrony. When used in combination with stable, optimal medical therapy, CRT is designed to reduce symptoms and improve cardiac function by restoring the mechanical sequence of ventricular activation and contraction.
Medtronic’s very brief and heavily product-focused page nevertheless has a neat animation of a failing heart before and after resynchronization therapy. Dr. Richard Fogoros gets a little more in-depth on About.com:
Cardiac resynchronization therapy – CRT
CRT uses uses a specialized pacemaker to re-coordinate the action of the right and left ventricles in patients with heart failure.
…
In approximately 30% of patients with heart failure, an abnormality in the heart’s electrical conducting system (called an “intraventricular conduction delay” or bundle branch block) causes the two ventricles to beat in an asynchronous fashion. That is, instead of beating simultaneously, the two ventricles beat slightly out of phase. This asynchrony greatly reduces the efficiency of the ventricles in patients with heart failure, whose hearts are already damaged.CRT re-coordinates the beating of the two ventricles by pacing both ventricles simultaneously. This differs from typical pacemakers, which pace only the right ventricle.
I was looking for information on clinical indications for administration of CRT. Apparently the roots of the problem are in bundle branch block. I’d say I’m off to a pretty good start!
My Qualifying Exam
Today begins the open-book portion of my qualifying exam, which I think makes me a Ph.D. Student as opposed to a Graduate Student if I pass.
My topic of research, for which I have one week, is Cardiac Resynchronization Therapy. I think I’ll post some of my findings here as I go. That way, I’ll have a record of my research, and any of you who might be interested in the subject can get up to speed along with me.
On my mark, get set, go.
ICDs, wandless telemetry, and encryption
Here’s something nobody has ever been able to tell me:
Do wandless ICDs (implantable cardioverter-defibrillators) employ any kind of encryption?
As far as I can tell, the answer is no.
Let me give you a little background. At the last Heart Rhythm Scientific Sessions (2005, in New Orleans) most of the big ICD companies were showing off their wonderful new “wandless telemetry” systems. Historically, ICDs have been programmed (after implantation) and interrogated with some variety of inductive communication. This was done by placing a “wand” over the part of the patient’s body where the device was implanted and then initiating communication. It has a short range, around a few inches. Device companies have begun to use radio-frequency (RF) communication instead, which has a longer range, something on the order of feet or meters.
This is a big problem.
Not one person I’ve asked (admittedly, sales people for the most part) has been able to tell me if the new RF (a.k.a wandless) telemetry communication is encrypted. I did some patent searching at uspto.gov, and found that no patents have been granted on anything like this yet. However, Medtronic did apply for a patent in September 2005. As the patent application says in its background, “With the advent of long range telemetry of messages, and the associated increase in communication range, the risk that a message can be compromised is increased. For example, a replay attack can be launched in which a message, or a piece of a message, can be captured and then maliciously used at a later time.”
So it does appear that someone is thinking about this. Most people don’t really think about or understand encryption, even technically-inclined people like medical device engineers.
Do you know anything about this? Do you know someone who might?
Helping the body fight cancer
There’s a nice overview (with links to abstracts) on Biosingularity about this discovery:
Biosingularity » Blog Archive » Newly discovered killer cell fights cancer
A mouse immune cell that plays dual roles as both assassin and messenger, normally the job of two separate cells, has been discovered by an international team of researchers. The discovery has triggered a race among scientists to find a human equivalent of the multitasking cell, which could one day be a target for therapies that seek out and destroy cancer.
“In the same way that intelligence and law enforcement agencies can face deadly threats together instead of separately, this one cell combines the ability to kill foreign pathogens and distribute information about that experience,” says Drew Pardoll, M.D., Ph.D., the Seraph Professor of Oncology at the Johns Hopkins Kimmel Cancer Center.