New ICD moves leads, reduces chance of infection

Implantable Cardioverter Defibrillators (ICDs) are cool. For people who are prone to tachycardia, V-Fib, or other rhythm disorders, it could be a lifesaver. An ICD is like having your own medical team with you all the time. The moment there is trouble they get out the paddles, shout “CLEAR!” and give you a life saving jolt. And very few people have to know you even have one.

But in most cases, the patient population for new ICD are older citizens. This 2007 clinical trial specifically tested the efficiency of pacemakers in patients that were 75 years old or older. But what about us younger folks who need an ICD? They usually aren’t recommended for the youngsters.

One of the potential problems are the ICD leads. The wires that run from the ICD have to go into the heart and connect inside of the heart muscle to deliver the shock if one is needed. Leads have to be strong, but flexible. You can have one or the other, but usually not both. At the Broken Hearts of the Big Bend Regional Forum on Congenital Heart Defects I attended in February, electrophysiologist Dr. Randy Bryant  said that most children who have either a pacemaker or an ICD needed to have their leads replaced. One of the more common reasons for the replacement is the Belly Flop into the swimming pool. Leads seem to have difficulty dealing with that!

And every time you change a lead, you run the risk of giving an infection a chance to get inside the body. The odds are low, but toss the dice enough times, and you’ll finally roll snake eyes.

And leads can just, for lack of a better word, wear down. They have to be connected to a certain spot inside of a muscle that is constantly in motion, with an owner who could turn, twist, or bend in any conceivable direction. As Dr. Martin Burke, Director of the Heart Rhythm Center at the University of Chicago Medical Center puts it:

“It’s a 98.6 degree, dynamic environment that pumps like a piston 60 to 100 times a minute; it’s a miracle they last 15-20 years in my mind.”

Burke has been part of a team that has tried to rethink the Defibrillator, take a good idea and make it even better. It looks as if they may be onto something: An Implantable Cardioverter Defibrillator (ICD) with leads that are not in the heart, but rather just below the skin. Putting the leads just below the skin (they don’t even go beyond the breastbone) means that the ICD has to deliver a shock that is two and a half times more powerful that the average ICD. But the computer that controls the ICD has also been improved. It can better detect heart rhythms that are unusual but not dangerous, and deliver fewer shocks.

The new Defibrillator (which is known as the S-ICD) has just entered clinical trials, so you won’t be able to go to your doctor and demand one. But in the future, hopefully it will become a common tool for CHDers and other heart patients.

Tags: ICD, Implantable Cardioverter Defibrillator, Pacemaker, University of Chicago