ICDs in Cadavers: Potential Risks and Learning Opportunities

I can still remember my first encounter with an implantable cardioverter-defibrillator (ICD). It was where all physicians encountered their first patient, the Gross Anatomy laboratory. The device was a large, shiny metal box that was similar in size and shape to a liquor flask. The leads (which seemed the size of television cables) were cut, and the pulse generator was lying discarded in the bottom of the tub. It would periodically and ominously beep, which was particularly audible when studying at night when the lab was quiet. By this time in my training, I was already entertaining a career in cardiac electrophysiology, so I found this mysterious device quite fascinating. But there was also something foreboding about this metal can with its chrome-shined finish, periodically beeping as if ready to deliver its 35 Joule lightning bolt. 

While I was contemplating this now archaic ICD, my wife-to-be, Kim, was in graduate school studying anatomy with her sights set on a teaching career. By the time I was a resident, she had secured her first faculty position teaching first-year medical student anatomy. It had been several years since Gross Anatomy and my first encounter with an ICD, and I had not thought much about that oversized can until Kim mentioned that she had several cadavers with ICDs, and wanted to know if I would be interested in coming to the anatomy lab and talking to the medical students about cardiac devices. I then thought of a bunch of live ICDs sitting in a pool of embalming fluid, and I asked Kim what they do with ICDs in the anatomy lab when removing them to make sure they are not active.

“We just cut the leads with scissors,” was her response.

This was during the 6949 lead fiasco, and I was aghast. I had thoughts of 35J shocks careening through pairs of dissection kit scissors, leaving unsuspecting students stunned and dazed.
“Well,” she said, “we have never had any problems.”

Maybe not. At least not yet. Repurposing otherwise normally functioning devices has been covered in the pages of this publication in the past¹, but what about ICDs that are encountered by medical and other healthcare professional students in the anatomy laboratory? Has anybody ever been shocked? Have any of them had tachycardia therapies deactivated? How are they disposed of? How do undertakers and pathologists, who also deal with ICDs, handle them? Most importantly, as medical professionals who deal with these devices on a daily basis, could we help make embalmment, post-mortem examinations, and dissections safer?

According to the American Heart Association, 10,000 patients are implanted with ICDs every month.² Therefore, the chance that these devices will be encountered in the anatomy lab, the funeral home, and the pathology lab is quite high. With the growing number of people receiving ICDs, as well as the fact that many of those who donated their bodies have had longstanding chronic illness such as heart failure, the number of devices seen during dissection will continue to grow. The risk to these students, pathologists performing autopsies, and embalmers preparing bodies for funeral homes, is probably low. I could not find any case reports of medical students being shocked during dissection. However, the risk is not negligible either. Cutting the leads can create electrical noise interpreted by the ICD at ventricular fibrillation and result in a shock. This could cause burns, atrial fibrillation, nerve injury, or possibly even ventricular fibrillation in the operator, and post-mortem discharge of an active ICD during autopsy has been reported.³

After having this discussion, I recommended that the ICDs be checked to make sure that the VT/VF therapies had been disabled. Whenever I have cared for an ICD patient that passes, I have always made sure the device was deactivated, and I assumed most of the ICDs in the anatomy lab had been turned off as well. Much to my surprise, only about half of them have had tachycardia therapies turned “off.” This has held up year after year as well as at different institutions where Kim and I have worked. In general, about half of all ICDs still have active shock therapies. 

This prompted me to search relevant literature, which did not take long because it is quite sparse. I could find no information regarding ICDs and cadaveric dissection, but there were a few papers in the pathology literature regarding post-mortem examinations. Additionally, I was able to find some information regarding ICDs and morticians.

A 2006 survey of embalmers from 100 Chicago-area funeral homes revealed that only four respondents ever even recalled interrogating a device.⁴ The most common reason cited was out of concern that the lithium-ion batteries can explode during cremation. This has been addressed in trade publications for embalmers, and interrogating ICDs and deactivating tachycardia therapies has now been recommended.⁵

In addition to safety issues surrounding live ICDs being flippantly handled, there are also issues relating to determining the cause of death and assessing the device for any malfunction. If a malignant ventricular arrhythmia was the cause of death, this could easily be proven by a device interrogation. All of us who work with ICDs know that they are far from perfect. Though the ICD represents an amazing technological advancement in the prevention of sudden cardiac death, recent advisories and recalls relating to leads, batteries, and ICD circuitry have shown us that these incredibly complex man-made devices, while generally quite reliable, are not perfect. Each manufacturer will proudly tout its low device failure rate, but the true failure rate of these devices is not known due to the low rate of post-mortem device interrogation and because less than one-quarter of ICDs are returned to the manufacturer after death.⁶ Because of the extremely low rate of post-mortem device interrogation, the actual incidence of device failure is likely to be significantly underreported. Returning more devices to the manufacturer after patient deaths could offer more accurate estimations of malfunction rates and causes for malfunctions, increasing the safety and reliability of future generations of ICDs. 

Whenever I am about to start a procedure, from a generator change to a ventricular tachycardia ablation, I try to think of all the possible complications, how I can avoid them, and what I will do if one occurs. This is because if a problem can happen somewhere or at some time, it will. I could find no reports of dissectors receiving shocks during cadaveric dissection, but with the number of devices these students are encountering, it is only a matter of time before it happens. This could unfortunately result in significant discomfort or even serious injury. Fortunately, it can easily be avoided. Obtaining a device interrogation is as easy as making a phone call. At my institution, I do not think a device patient ever crosses the threshold in the ER without getting an interrogation, as it is so easy to obtain. These devices could easily be checked in pathology labs, funeral homes, and anatomy labs. It is our job as medical professionals who deal with devices to educate anatomy instructors, pathologists, and embalmers about the risks of “live” ICDs and the steps to avoid potential harm. Everyone who has to remove these devices should be given the contact numbers for the device manufacturers so they can be checked for any possible device malfunction and to make sure tachycardia therapies are deactivated. The first time Kim called one of the device reps to check an ICD, the response was somewhere along the lines of, “You want me to do what?” However, from that time on, they know to expect it every September, and are very helpful. If immediate assistance is needed and not available (class cannot be held up when ICDs are encountered!), handling the ICD with two pairs of neoprene gloves can protect against a shock.⁷ A torque wrench to unscrew the leads rather than cut them should be available, and a potentially live pulse generator should be placed in two pairs of gloves rather than be discarded in the embalming liquid in the bottom of the tub. The devices should never be incinerated — as most cadavers eventually are, as well as many deceased persons encountered at funeral homes — this could result in the lithium-ion batteries exploding. All devices should at bare minimum be interrogated, and preferably returned to the manufacturer, to improve actuarial data regarding device reliability, malfunction, and longevity.

The increasing number of ICDs seen in cadavers also provides us with some unique opportunities. It allows us to raise awareness of sudden cardiac death and to educate students about the devices they will undoubtedly encounter later in their training and practice. It also provides us with an opportunity to actually see what leads look like in the heart. Given the minimally invasive nature of our trade, we rarely if ever get to see how a lead adheres to the SVC, or what an LV lead looks like in a coronary sinus branch. However, we get to see all this in the anatomy lab. 

I still wonder why that ICD was beeping. Was it at ERI? Did it detect a high lead impedance? Was it trying to deliver 35 Joules to some unsuspecting student cramming for the thorax practical? I suspect it ended up in the incinerator, exploded, and its secrets were never revealed. Fortunately, at least in this case, no one was harmed!

Disclosure: The authors have no conflicts of interest to report regarding the content herein.   

References

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