The LifeVest™ is a wearable defibrillator which became commercially available after FDA approval in October 2002. Dr. John Lobban, Director of Electrophysiology at Monongalia General Hospital in Morgantown, West Virginia, began using it after two of his patients died while waiting for implants. The LifeVest will continuously monitor a patient’s heart, and if the patient goes into a life-threatening arrhythmia, the device will either: 1) allow the conscious patient to interact and stop a treatment shock; or 2) if the patient is unconscious, it will deliver a shock treatment to restore their heart back to a normal rhythm. Being able to stop the treatment helps the patient prevent what may be false detection, a key difference between the wearable defibrillator and the implanted defibrillator. In addition, if the patient is unconscious, the device will continue to give alarms and spoken warnings to bystanders that a treatment shock is about to be delivered.

Of the approximately 450,000 sudden cardiac arrest (SCA) deaths in the U.S. each year, an estimated 95% die within 10 minutes of the event's onset. For those patients, every moment is crucial while waiting for EMS to arrive. Therefore, the LifeVest is very beneficial to SCA patients, especially because they are able to rest comfortably at home, and are not confined to a hospital bed. The LifeVest is manufactured by LifeCor®, which was co-founded in 1986 by Dr. Stephen Heilman.

How did you become involved in the field of EP? How long have you been at Monongalia General Hospital?
In my first month or two of my cardiology fellowship, a professor asked if I would be interested in doing electrophysiology, and I didn’t say no. So you could say I was sort of tricked into it! There was an opening for another person in the electrophysiology department, so I was groomed to be their second electrophysiologist. This was back in 1992. I have been at Monongalia General Hospital for 6 years.

What can you tell me about the LifeVest?
I use the LifeVest, mainly from either my office or from the hospital, if there are patients who are sent to me because there is concern of sudden death and they have the substrate for it. In terms of scheduling, it is very difficult to get people scheduled for efficient workups. However, when you are working with patients who are prone to sudden death, you want to be able to protect them as soon as you can. With only 24 hours in a day, it is hard to schedule them all in an efficient manner. It is probably a 3–4 week wait between meeting with a patient and working them up for an EP study or ICD implant. I have lost two of my patients to sudden death in that window of time before the LifeVest came on the market. So when this product became available, I was interested in it, as it provided a way to bridge patients to their procedures.

Figure 1

LifeVest Mannequin product shot (front).

What results have you seen at the Monongalia General Hospital? How many of your patients have now used the device?
I am not sure how many patients of mine have used the LifeVest, but so far, no one has yet been treated by their LifeVest. However, I have only been using the LifeVest for a short time, after it was first put on the market.

What types of patients does this device benefit? Do you prescribe it to all patients awaiting testing who have had an MI, or to patients following surgery?
I use the LifeVest for post-bypass and post-MI patients, because at that point in their convalescence, their ejection fractions are down. When they are having unsustained VT, I prescribe a LifeVest and then reevaluate their ejection fractions in a month or 6 weeks and risk stratify them at that time via an EP study or by implanting a defibrillator. If their ejection fractions remain really high risk — based on the MADIT trials — I will have the patient continue to rest, get a device on them, let them convalesce for a month and see if their ejection fractions improve. After their procedures, I give patients a month or two to recover and see if I can get them out of risk without having to intervene. I try to use the LifeVest to bridge them to recovery, if they are interested.

Figure 2

Figure 2. Response alarm: If a patient is conscious when an alarm sounds, he/she can prevent the shock by simultaneously pressing two response buttons.

What is your criteria for prescribing the LifeVest?
If the patient has madit II criteria for implantation, syncope with non-ischemic cardiomyopathy, or a documented complex heart rhythm, until they are worked up, I will offer that kind of a patient a LifeVest, independent of what the workup shows. If their workup ends up being negative, then the LifeVest is discontinued. If the patient comes in and needs protection against sudden death, I will implant a defibrillator and discontinue the LifeVest at that time.

What has been the average amount of time patients have to wear the LifeVest?
The average amount of time for my patients is approximately in the 21- to 28-day range, although it could be up to 5 or 6 weeks. To my knowledge, I don’t think anyone has worn it for 2 months yet.

Figure 3

LifeVest on model.

What has been patient response? Are there any activities that are restricted? Can the patient wear the LifeVest when sleeping?
Most patients are comforted by its presence, but are not comfortable in having to wear it. They can take it off if there is a loved one with them. In addition, I ask them to wear it if they are alone or when they are asleep. If they need to take it off to shower or just for their own sanity, I let them do it, as long as there is someone with them who can put the vest back on them and call 911 should they arrest while they are not wearing it.

Are there different sizes and models?
I am not sure how they fit the vest — the people at Lifecor do that for us. They bring the LifeVest to the patient — whether it is at home, here, or the office — fit it for them, and explain how to use it. They also show them how to download information and instructions for use in case it is reading incorrectly.

What are the components of the LifeVest?
There is the defibrillator itself, which is worn on the belt. There is also a vest, which wraps around the patient’s chest, and is connected to the defibrillator.

What happens when the device detects an irregular heart rhythm? What does the patient experience? What if the patient is unconscious?
When this happens, the LifeVest will alert the patient that it is about ready to treat him/her with a shock. The patient has two response buttons on the LifeVest that, as long as they are conscious and can press them in, will withhold shock and the alarm will stop. If the patient loses consciousness and thus is unable to press the button, then the device will deliver its therapy. The LifeVest is designed to cut down on inappropriate shocks. We prescribe it for a standard set of numbers — in terms of shock this, but don’t shock this — so that the patient has a little control over it as well, and they can prevent it from delivering shock.

In what other ways are physicians able to monitor the patient? Can they check ECGs?
The LifeVest downloads information through the internet to the Lifecor people, which we are then able to access. I review strips quite frequently that are obtained through the LifeVest. I have never prescribed it for diagnostic reasons, though.

How does the LifeVest compare with other technology available today such as AEDs or ICDs?
The implanted device will rest assuredly prove more reliable because it doesn’t detect patient movement or handle human error. It is more comfortable, especially once the surgical healing process takes place. The patient doesn't have to remember to put it on and take it off or wonder if the battery is good, etc. One disadvantage to the implanted device is that the patient has no control over it — the patient cannot push a button to prevent it from shocking if they are still conscious. They could theoretically use a magnet to prevent it from doing it, but I don’t recommend that, I let it on purpose shock people to keep them awake, because they can probably safely drive if it prevents them from blacking out. Thus, the implanted defibrillator is better treatment in the big-picture, long-term management side of it than a LifeVest would be.

In comparison, an AED needs a bystander, so if a person goes into arrest, then the person cannot rescue themselves, whereas a person with a LifeVest can. Also, if a patient is alone or asleep, or if no one is there to use an AED, then the patient is probably going to die. An AED would be more appropriate to have in a mall, airplane, police car or football stadium, so if a person goes into arrest, someone could use the AED on them and rescue that patient before an ambulance would have time to arrive. The LifeVest, on the other hand, would automatically treat, independent of bystanders. That is sort of how I use the LifeVest — the patient can use it as an AED in case they need a break from it — as long as their loved one is there and can get them back in the vest and call for help if an event occurs.

What kind of other advances in electrophysiology do you think we will see in coming years?
The next frontier for EP would be curative therapy for atrial fibrillation. This is the so-called “last frontier” of the one rhythm that we have very little good therapy for right now. In terms of defibrillation and sudden death prevention, I think the technology will continue to improve; however, the main issue now is that roughly one-third of patients who would benefit from a defibrillator are not getting them. I think the first madit trial was poorly understood, and the second madit trial has not yet gotten people’s attention the way that it probably should have. It seems that you have to jump through hoops to get defibrillators now; however, they are cost effective and a good thing.

For more information about the LifeVest, please go to Lifecor’s website: www.lifecor.com