James L. Januzzi, MD: Hi. I am Jim Januzzi, professor of medicine at Harvard Medical School and director of the Cardiac Intensive Care Unit at Massachusetts General Hospital in Boston, Massachusetts. Welcome to our program today on evaluating and managing sudden cardiac arrest in the patient with newly diagnosed ischemic heart failure.

Joining me today is a great panel. Seated to my right is Paul Hauptman, professor of internal medicine in the Division of Cardiology and assistant dean of Clinical and Translational Research at Saint Louis University School of Medicine in Saint Louis, Missouri. Paul, welcome.

Paul J. Hauptman, MD: Thanks, Jim.

Dr Januzzi: To Paul’s right is Linda Tavares, an acute care nurse practitioner at the Bon Secours Heart and Vascular Institute in Richmond, Virginia. Linda, welcome.

Linda Tavares, ACNP: Thank you so much, Jim.

Dr Januzzi: Great. The goals of the program today are to define the newly diagnosed ischemic heart failure patient and their risk profile for sudden cardiac arrest (SCA). Our panel is going to guide us through this topic, which is quite complicated but very interesting to discuss. We review guideline-directed medical therapy for the management of the patient with heart failure, particularly those patients after acute myocardial infarction (MI) and at risk for sudden death, as well as assess the potential value of the use of a wearable defibrillator as a bridge to implantable cardioverter defibrillator (ICD) implantation. I would like to start with a case that is very useful.

Dr Januzzi: This is a 68-year-old man with a history of type 2 diabetes and chronic kidney disease who presented with an acute MI. He presented with many hours of chest discomfort; unfortunately, this was a delayed presentation. His electrocardiogram showed signs of ST segment elevation, implying an anterior wall infarct. He is taken urgently to the cardiac catheterization laboratory, where he is found to have an acutely occluded left anterior descending artery (LAD) and chronic coronary disease elsewhere. The LAD is opened, stented, and postprocedure he is stable but found to have a left ventricular ejection fraction of 20%. He has moderate symptomatic heart failure, as well as some degree of ventricular irritability on the monitor. He is started on a fairly standard medical program of aspirin with dual antiplatelet therapy as well as β-blockade, angiotensin-converting enzyme (ACE) inhibition, loop diuresis, and spironolactone (mineralocorticoid receptor antagonist [MRA]).

We have a very well medically managed patient after MI, but what else should we be thinking about? Paul, what goes through your mind in these cases?

Dr Hauptman: There are always the "big 3." (1) Is the patient going to have recurrent infarction? (2) Is the patient going to develop congestive heart failure? And (3) What is the risk of sudden cardiac death (SCD)? I would love to believe that the medication is truly standard across the board. I think those medications are instrumental, especially the MRA, the ACE inhibitor, and the β-blocker, in reducing the risk of SCD early; but it is finite, it is real, and it is heavily associated with the EF. He has a window here of concern.^[1-3] It is too early to put in a defibrillator. The risk remains, and the lower the EF the greater the risk, so if you have an EF of 35% to 40% after MI, obviously your risk is going to be lower than in this particular case of 20%.

Dr Januzzi: We know from studies such as the VALIANT study that the risk of SCD is highest early on and falls gradually over a period of time.^[2] It never disappears, though. That is part of the issue here. Good medical therapy is critically important. Linda, can you speak to the role of the advanced nurse practitioner and other types of caregivers in the hospital for application of guideline-directed medical therapy and how we might do a good job there?

Ms Tavares: I agree with Paul with regard to the medical therapy. We certainly do not want to underestimate the importance of the patient’s LVEF, but I think looking at this post-MI patient you have to think about the dormant myocardium. My interventionalist has now gone in. He has done a fabulous job opening that vessel, and increased perfusion to this myocardium that clearly has been down for some period of time because, as you indicated, it was a prolonged presentation before he came in. We have to worry about that myocardium hibernating and then waking up, as I like to tell my patients, over time. We do not know how long that will take, but I think that it clearly paints that risk picture. We have to think about our other options and how we can best protect this patient for this next period of time. The wearable defibrillator is a great option.

Dr Hauptman: That is actually a fundamental point -- the risk for SCD is dynamic. If we were to see this patient in 6 months we might have a very different concept of what that risk is compared with what it is very early post MI.

Dr Januzzi: We will talk about the wearable defibrillator, but before we get to that let us talk about other bridges we need to cross, one of which is medical therapy. This patient that I presented had a very aggressive medical program instituted in their situation. What have we learned about medical therapies to prevent SCD in patients at risk?

Dr Hauptman: We published a paper 3 years ago that demonstrated a surprising underuse of β-blockade in the period leading up to implantation of the defibrillator.^[4] It increased, it spiked after implantation, presumably because there was an opportunity to treat the patient. Patient needs to be discharged on a β-blocker. The fact that there is underuse is unfortunate because, as you know, β-blockers do a lot of things in patients with LV dysfunction.

Dr Januzzi: Such as what?

Dr Hauptman: Obviously, decreasing the risk of SCD, potentially improving EF. Admittedly, that is less likely in a patient with an established ischemic cardiomyopathy as opposed to patients with nonischemic cardiomyopathy.

I would also argue that perhaps patients are prescribed β-blockade, but if they are actually not taking it represents a marker of poor adherence. If patients do not adhere to a β-blocker prescription, how adherent will they be for follow-up when they get a defibrillator?

Dr Januzzi: It is a marker of care adequacy, to some extent. We definitely see β-blockade in heart failure; in the chronic setting it does have effects on reverse remodeling and does affect EF. It is a bit more nuanced in the post-MI patient, of course, especially in someone with a prolonged infarction, but it’s still critically important on the basis just of reducing SCD. I would agree entirely that it’s very much underutilized. The big question that was asked, of course, is why not just go straight to a defibrillator? If we know someone with a low EF after an MI why not just implant a defibrillator? Linda, what are your thoughts on that?

Ms Tavares: I think the DINAMIT trial speaks to that; they found out that ICD therapy does not reduce the mortality in these high-risk patients, but clearly they are at risk for SCD.^[5] What can we do in that interim period? I tell my patients that we have that protection. Hopefully, over time their LV function will improve after revascularization, and now that we have got them on optimal medical therapy. In the interim, we have that protection should it not improve and should that hibernating myocardium become arrhythmogenic.

Dr Januzzi: In DINAMIT we saw a reduction in SCA, but it was offset by other issues aside from the arrhythmic complications. It is a challenging situation for us as clinicians. We deal with this all the time. This is a very real-world issue, so I have thought about this. I have a family member with a history of SCD; resuscitated, thankfully. I bought an ambulatory external defibrillator (AED) that I have in the trunk of my car. I have never had to use it in approximately 7 years, thankfully, with several battery changes. Why not give an at-risk patient an AED? Paul, any thoughts?

Dr Hauptman: It has been described in the HAT study, which was a remarkably large study that does not get a lot of attention; it demonstrated that at-home defibrillation does not work.^[6] There are a host of reasons why that might be, but in this group of patients with a history of anterior MI the mean time from infarction to the randomization was 1.7 years. It was not quite the patient that we are describing here, who is very early post-MI. You might argue that if it is very early post-MI perhaps there would be a role. The mean EF of the patients in the study was 45%, but there really was no difference in outcome between the group that had an AED and the group that did not. In part, you have to be close enough to the AED for it to be useful. Of course, the literature is replete with descriptions of publicly placed AEDs; as you may know, the one place that you want to be if you are going to have an SCD event is a casino.

Dr Januzzi: Absolutely; no question about it.

Dr Hauptman: Better than at home, it turns out.

Dr Januzzi: My understanding of the HAT study was that the results essentially were that the hazard curves were superimposable.

Dr Hauptman: That is correct.

Dr Januzzi: There was really no difference, but your point is important to emphasize for the viewers, that obviously AEDs play a huge role. In this niche, however, there was not an effective application of the technology; also, it is complicated to use. Patients may be elderly, they may not understand how to use the device. Of course, a person needs to be with the patient in order for the patient to receive the therapy.

Dr Hauptman: That is correct. That was considered a limitation. You need someone physically present who can competently access and use the AED.

Dr Januzzi: The unmet need, therefore, is this idea of having a temporary device that can automatically recognize arrhythmia and deliver a therapy successfully without requiring us to subsequently implant a device. That is really where the wearable cardioverter defibrillator comes about. Linda, I really want to hear your thoughts on the success of this device and the thoughts of someone who "uses it in the trenches," as we say. You talk to your patients all the time. What can you tell them about how successful the device is? We get specific regarding how it is worn and how it works.

Ms Tavares: There is a 98% first-shock success rate, which is outstanding. I explain to my patients that this is an insurance policy. They have had a big event that often gets their attention when they are in the hospital. They are usually scared to death in the hospital, not sure what things are going to be like when they go home. They are on new medications. How does all this fit together? We have given them a protection device to wear; the wearable defibrillator is like a sports bra, if you will. It can fit a variety of patients.^[7]

Dr Januzzi: What about sizes?

Ms Tavares: It comes in a variety of sizes up to, I believe, about 52-in chest.

Dr Januzzi: Would it fit Paul or me pretty easily?

Ms Tavares: You cannot underestimate or exclude a patient. Typically, I talk to the company. They send out technicians to measure the patient and help me get the devices for them; it is based on a chest measurement as opposed to a total body weight. It is a wearable device. The electrodes are quite fascinating. They were developed by the National Aeronautics and Space Administration, and the astronauts wore them. They are not sticky, which is typically what we think of when we think of electrodes in a hospital-type setting -- they are a dry electrode. The device also includes 2 chambers that have gel capsules in them. They look like a vitamin container and they are in the front and the back of the device. When the device deploys this gel - - and it will inform patient - - is the only time the patient would feel a wet sensation.

Dr Januzzi: Does the patient get warned that there is an arrhythmia detected and that a shock may be coming?

Ms Tavares: They do. Actually, the sequence of events starts out with a very loud beeping sound, and then the device actually talks to the patient and the bystanders, giving direction with regard to what is going to happen next: it is going to deliver a shock; everyone needs to evacuate the area; do not touch the patient; those kind of things. The patient also has the option to abort the shock because we are using this for SCD. SCD means they have had an arrhythmia and are unconscious. They need the device to shock them to bring them back to consciousness; if they are sitting here talking as we are talking and the device is acting like it is going to shock then they might decide to abort this shock.

Dr Januzzi: My understanding is that they need to use two fingers to depress the buttons and hold them for a period; this avoids the potential risk of accidentally aborting a shock if, for example, they lose consciousness at the time that they are going to push the buttons. Is that correct?

Ms Tavares: Correct. Only the patient can abort the shock.

Dr Januzzi: Interesting. What about compliance? How do people feel about wearing this? Do they stick with it?

Dr Hauptman: My personal experience is yes, they do, but it is not universal. Actually, it is a very interesting question. I would like to ask Linda. In discussing this technology with patients, how receptive are they? Have you been able to figure out which patient phenotype, if you will, is really going to be adherent and is going to therefore gain the benefit from the device?

Ms Tavares: That is a great question. Certainly, we want our patients to be adherent to all the therapies that we provide. Patients who would be excluded would be those who may not have the mental faculties to deal with a device such as this, or perhaps have some dramatic psychological problem for which this may cause more stress or anxiety burden, so you need to know your patient. When my patients come in and they have had an acute MI, I equate it somewhat to them having broken a leg. If someone has broken his or her leg we put it in a cast. The patient is not going to be able to move it for a period of time and knows he or she cannot do certain things as a result of being in a cast. When they come in after having had an MI, they feel terrible for that period of time, but we tune them up and they feel somewhat better when they leave. They cannot get their heads around having had a major cardiac event; the goal of a lot of therapy, including β-blockers, is to rest that heart. We are slowing everything down, lowering the blood pressure, lowering the heart rate, in effect acting as a splint would act to help a bone heal. The wearable defibrillator is another tool in the chest, if you will.

Dr Januzzi: My understanding is that they are a captive audience. Our patients are often very willing to take certain things under consideration; given the possibility that it is a short-term therapy, the compliance can be very good. The data suggest that up to 90% compliance after the initial few days seems sustained; given the combination of the design of the device as well as the compliance, it appears to be an attractive option.^[8] What do we know about its efficacy? What do the data say?

Dr Hauptman: There is a recent report from the registry post MI that used a device by ZOLL. Epstein and colleagues published an interesting article in 2013 in the Journal of the American College of Cardiology.^[9] In over a 7-year period, over 8000 patients early post-MI had a relatively low shock rate . It was 1.6%, those patients generally receive more than 1 shock. Also, the shock was more likely to be delivered when the EF was <30%, as in our patients; of note, it was generally within the first month following the MI.

Dr Januzzi: Interesting.

Dr Hauptman: Given your expertise in biomarkers, do you think there is a role very early after MI for some form of biomarker panel to further risk-stratify that patient? Obviously, if you are in that 1.6% it is a great thing, but there are also a lot of patients who are wearing this who will not - - thank goodness - - need a shock.

Dr Januzzi: I think that the ultimate question will be whether we can use objective means to assess who might go directly to an ICD versus the short-term wearable defibrillator, and biomarkers have some promise. The issue with biomarkers in this setting is they are affected by a number of processes that are present in patients like this, including the infarct, of course, and the remodeling of the ventricle. How much of the signal you detect is a risk for SCD as opposed to progressive ventricular remodeling. Still, the natriuretic peptides, highly sensitive troponins, soluble ST2, all appear to predict SCD in patients with structural heart disease, so there is a lot of promise there. There is no question. Ultimately, as we start looking at more precision methods to phenotype our patients, that is likely to be a part of this assessment, together with imaging and other clinical tools. We know that the device is effective. The data of Epstein and colleagues suggest it.

The Cleveland Clinic had a matched analysis of patients after PCI suggesting that those with low EF and higher risk for SCD had greater efficacy with the defibrillator.^[10] We have a sense that that is a reasonable group of patients, and we use it quite a bit at Massachusetts General Hospital, and I am sure at your institution. There are other areas in which there may be some benefit; Linda, you work in an intensive care unit (ICU) that is medical-surgical.

You see not just the patients with straightforward single-vessel disease who are stented and sent home. What about other groups, such as patients after bypass surgery, for example?

Ms Tavares: That is a great example. I worked for the cardiac surgery team for a number of years before I went into the ICU setting, and often my cardiac surgeons are great. They do a great job with revascularization, and then they transfer it to the advanced practice team to manage and transition that patient’s care. This is a great place to make sure that our patient is protected. They have been revascularized; we do not know how much that myocardium is going to come back over the next 40 to 90 days, this wearable defibrillator is yet another protection. The other thing that the wearable defibrillator does is provide that patient a sense of connection and contact with his or her provider team, and the knowledge that something has happened. Every day Every day the patient wears the device is a reminder to be adherent with medications, diet, and exercise.^[11-13]

Dr Januzzi: That is interesting.

Ms Tavares: There was a study to prove that very point.^[10] The data are also available to the provider. Patients often feel as though somebody is looking after them for that period of time.

Dr Januzzi: It not only reduces their risk for SCA, but it may also lead them to a more adherent lifestyle, to therapies beyond the wearable defibrillator, which may further reduce their risk for SCD.

Ms Tavares: Exactly.

Dr Januzzi: In some ways, the compliant patient is compliant with all aspects of care, not just that one area. I would emphasize to the viewers that post-bypass surgery patients are a really interesting patient population because they represent, in some ways, a so-called "reset." They come through surgery; they are on medical management; their medicines change; they may be somewhat vasoplegic, so they do not achieve the big doses of β-blockers we would like to see them receive. Revascularization, surgically speaking, can really turn the ventricle around, and so we often find ourselves in an uncertain situation. After ventriculoplasty, after the apex of the ventricle is taken out, and a patient’s EF is superficially higher than it really is after the ventricle is reconstructed -- these patients are all interesting conundrums. The defibrillator seems to work in these patients in whom you see up to a 10% risk of SCD after revascularization, surgically speaking.

Paul, you and I talk a lot about heart failure. I was a resident when you were a fellow and junior attending at Brigham and Women’s Hospital (Boston, MA) many years ago, and things have changed a lot in the world of heart failure. Although we are focusing on the ischemic patient here, there are other areas in which the wearable defibrillator may have a role.

Let us just think a little bit about the other forms of heart failure we see, including the nonischemic heart failure patients. What do you think about the use of the wearable defibrillator in the nonischemic patient or the newly diagnosed patient? Let us say a patient comes into the emergency department with a low EF. What do you think about them?

Dr Hauptman: That is a great question. There is a defined role in the nonischemic cardiomyopathy setting. The struggle we have is to distinguish between new diagnosis of cardiomyopathy and new onset of cardiomyopathy.

Dr Januzzi: It is a big difference, is it not?

Dr Hauptman: What we generally would say is that if your end-diastolic dimension is 7, 7.5, or 8 cm, and you have a left bundle branch block pattern on your electrocardiogram, the likelihood is this is a new diagnosis, but it is not new onset. We are often tempted in those settings to say this is an established cardiomyopathy. There may be some improvement. It is very rare for a left bundle branch block to go away, although there are some cases of this. We had one recently in which the end-diastolic dimension actually reached 9.5 cm and the patient had reversal.

Dr Januzzi: They had reversal?

Dr Hauptman: They had reversal.

Dr Januzzi: Incredible. That is unusual.

Dr Hauptman: Very unusual. In fact, we are writing up a case because it is so unusual. The conventional teaching would be that person has an established cardiomyopathy. Those are the patients with new-onset cardiomyopathy who are the most worrisome; although by the strictest interpretation of the rules you cannot put an ICD right away, the patient should be put on a β-blocker, ACE inhibitor, and so forth. That is really where we target the use of the wearable defibrillator. If you have a patient who is not very dilated, has a narrow complex QRS, and could be tachycardia induced or have some other reversible cause, that tends to be a lower-risk situation.

Dr Januzzi: It is important to emphasize the data from multiple clinical trials, that suggest that those with minimal congestive symptoms often are the ones at highest risk, and so it is the patients who sometimes are viewed as being, for lack of a better way of putting it, less sick.^[14] We have the most to lose there, I would argue.

Dr Hauptman: The patient in class IV heart failure is likely on a trajectory to die of progressive heart failure and congestive symptoms. I should also point out that if there is an arrhythmic mode of death for those patients, it may be bradycardic. It may be pulseless electrical activity. Neither of those modes would actually be treated by the wearable defibrillator, or by the implantable one.

Dr Januzzi: It is important to emphasize that good medical therapy can clearly improve EF, reverse remodel, and reduce the risk for SCD, but as we talk about in the guidelines, the patient with improving EF still has higher risk.^[15-17] If my patients come in with an EF of 30% as a newly diagnosed or newly recognized case and we aggressively treat them medically, and their EF comes up to 45% or 50%, I warn them this may be a transient improvement over time. We obviously need to watch them, but that is where excellent care team collaboration, medically in the hospital with nurse practitioners, physician assistants, caregivers, our heart failure specialist, and then outpatient care, is so crucially important.

Dr Hauptman: I would say, too, that there are moments in the care of patients with heart failure or LV dysfunction that one remembers, and one of them is being able to tell a patient with a wearable defibrillator that his or her EF has now improved to the point that not only can the wearable defibrillator be removed, but that in-depth discussion about the implantable defibrillator is not necessary either, at least not now. That is a big step for a patient, and as a clinician I certainly enjoy those moments as much as any.

Dr Januzzi: It is a teachable moment for the patient as well because they understand your decision making and how things may change over time. Linda, in your experience where else might we have a niche for the use of - - and it is not a small niche - - wearable defibrillators? Where else might we consider their use?

Ms Tavares: Certainly: somebody who is listed for cardiac transplantation; patients undergoing evaluation for a conduction delay or long-QT syndrome; patients who have had ventricular tachycardia >48 or 72 hours after an MI who have a preserved EF.

Dr Januzzi: Those are all very important. I am glad you brought up both the long-QT syndrome patients. These patients have SCD in their families, and you are evaluating them. That is a window of opportunity that could potentially be missed. Of course, this comes up all the time. Patients, after leaving the coronary care unit, are on the step-down unit. They are 3 or 4 days out. They have had ventricular tachycardia, and either their EFs are abnormal but not below the level we worry about, or they have frankly normal EFs. The patients go home and have SCD the next day, but they exhibited none of the conventional risk factors other than some ventricular irritability.

To some extent, it is very important that judgment be part of the decision making because that is one of the advantages of a nonimplantable device such as the wearable defibrillator. Who makes the decisions? How do we decide? I am going to ask both of you. Paul, at your institution, who makes the decisions? Who decides a patient is eligible for a wearable defibrillator and follows through on that?

Dr Hauptman: It is an interesting dynamic. It may not be on our radar screen with every patient in every clinical setting, and what I found is, if I am not thinking of it, one of our fellows may be thinking of it. If one of our fellows is not, one of the nurses on the floor brings it up. We have a nurse practitioner who rounds with us as well, and she often will prompt us. As we gain awareness of this it becomes a team decision. People then have to decide whether they believe that the patient can handle it psychologically and medically, and then we move forward. I have not seen it delay discharge, which is also a very important thing; although, ideally you would be thinking about this the day before discharge to facilitate a smooth transition.

Dr Januzzi: How about you, Linda?

Ms Tavares: I would say, very similarly, we have multidisciplinary rounds every day in the ICU, and I lead those. Whether I come up with it, or the bedside nurse, or my case manager, it is a team approach.

Dr Januzzi: Yes. In our institution it is the same. General cardiologists and interventional cardiologists both equally manage these post-infarct patients, but we all work very closely in a care team model with extenders, including nurse practitioners, and frequently all of this happens through the collaboration of these various caregivers. I would also emphasize that the electrophysiologists at our institution are big champions of it. There is an ongoing randomized controlled trial looking at the use of the LifeVest® (ZOLL Medical, Pittsburgh, PA) after MI, the VEST study; looking at this in a scholarly, randomized fashion is very important.^[18] It is a terrific technology, and understanding its best application is very important.

Dr Hauptman: I think you also are hinting at another aspect of care; when we use a LifeVest I am always in touch with the electrophysiologist to inform him or her that we are using it, and that we will be in touch based on what happens to the patient’s EF in the next 45 to 90 days.

Dr Januzzi: Electrophysiolgists really face a lot of difficulties because although the guidelines are fairly well articulated as to how we should be thinking, based on their EFs and signs of risk for SCD, there are some patients who seem clearly destined for a defibrillator.^[19] We can plug them in, get them ready, and have them wear the vest until we know they are ready, but there are patients in a "gray zone " who may improve. I have great respect for the challenges that the electrophysiologist faces regarding the potential need to implant a device in a patient who might not meet criteria. Indeed, the Heart Rhythm Society guidelines really incorporate the use of the wearable defibrillator with respect to decision making.

I am going to ask our panelists for some final thoughts, some concluding remarks about what they think the future for LifeVest use might be for our patients, and any other thoughts that may be on their minds. Paul, why do we not start with you?

Dr Hauptman: I think that the LifeVest has become part of medical therapy for a patient with low EF following MI; as we make certain that patients are on optimal medical therapy, I think it is a strong consideration. What I like about it is that it is very time limited -- you know that it is not permanent, whereas an implantable defibrillator is, in most cases, forever. Our obligation to our patients and our obligation to the medical system is to use that technology wisely, and so much goes on in that first 90 days after MI, and the first 90 days following initial onset of congestive heart failure from nonischemic causes, that the dynamic nature of EF at that point really drives home the point that you need a bridge. If the EF remains low at the end, you have the implantable option.

Dr Januzzi: Linda?

Ms Tavares: I agree. Your comments are very good, Paul. Bringing home the point that this is an outward, visible, and tangible mechanism encourages patients to accept that something very serious has happened to their hearts. It reinforces the importance optimizing their medical therapy, and helps them accept the fact that they may need an implantable defibrillator The data with regard to adherence and follow-up are very good, and it is an intervention that "does no harm." You do not lose anything by doing this. Certainly, the patients can decide they do not want to wear it, but I think as providers we want to offer the patients the best possible outcome that we can.

Dr Januzzi: Absolutely. That is a great concluding statement. This has been great. I really appreciate you spending the time to talk about this with us.

Dr Hauptman: Thanks, Jim.

Dr Januzzi: I would like to thank the panelists and to thank you, the audience. This has been terrific. I want to remind you that if you wish to click on the Earn CME Credit link to take the CME posttest and evaluation. Thanks for joining us.