The Future of ICD's?

Returning from a weekend conference, I am feeling refreshed from professional discourse, idea sharing and not a little merriment. One of the most interesting presentations (for me at least), was an intriguing talk given by Dr. Riccardo Cappato on the initial patient experience with the still investigational subcutaneous ICD's. The positives of this novel approach to CRM device implantation were immediately apparent namely the following:

• Fluoroscopy is not required intraop


• risk of complications such as pneumothorax, hemothorax, myocardial perforation and lead dislodgement are completely removed


• No introduction into the vascular system - especially useful in pediatric patients and patients with difficult or not vascular patentcy


• No risk of SVC vein occlusion or need for possible laser lead extraction for subsequent lead revision


• lower risk of lead dislodgement

These risks are minimized or bypassed due to the fact that the lead system is implanted entirely subcutaneously. The defibrillation coil runs parallel to the left aspect of the sternum and the lead body is then tunneled along (approximately) the 6th intercostal space to the device which is implanted parasternally (approximately 5 inches inferior to traditional placement and slighly more lateral).

The initial experiences that were reported described a virtually equivalent tolerance to alternate device placement, and not perceived increased patient discomfort when compared with traditional placement. DFT's were also successful at 65 joules or less allowing for a safety margin of at least 15J, given the devices maximum output at ~80 joules. This method of course is contraindicated in those who DO have an underlying pacing indication. That being said, the investigators did note that success of the post-shock pacing at higher than traditional values.

I personally am cautiously optimistic about the early success of this approach to implantation. I would like to see how the lead behaves chronically while it is in perpetual contact with subcuticular tissue. How will the leads perform chronically? How (if at all) will lead maturation manifest? Can the defibrillation coil become indurated with scar tissue? Will weight changes or either a decrease or increase in fat affect DFT's? How will that impact the leads efficacy? Only time will tell.

Discuss...