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Sudden Transitional Death Risk: When an ICD Isn’t the Answer WWW.RN.ORG® Reviewed July, 2014, Expires July, 2016 Provider Information and Specifics available on our Website Unauthorized Distribution Prohibited Presenters and Moderator Presenters: Tom Deering, M.D Electrophysiology and Arrhythmia Service, Piedmont Hospital, Atlanta, Georgia, USA. Helmut Klein, MD Director of Cardiology, University of Magdeburg, Magdeburg, Germany Leonard Ganz, MD Director of the Electrophysiology Service, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Moderator: Alfred Buxton, MD Sudden Transitional Death Risk: When an ICD Isn't the Answer (CE for Nurses) Course Overview COURSE INTRODUCTION/METHOD OF PARTICIPATION To complete this course, you must do the following: Read the Needs Statement/Overview and Course Objectives. Study the Terminology. Study the Content Review. Complete the comprehensive Post Test To receive 1 hour of Continuing Nursing Education credit for the course, complete the comprehensive post test and activity evaluation form at the end of this activity, and follow the instructions to receive your certificate. NEEDS STATEMENT / OVERVIEW In this document three noted experts provide a discussion of the risk of sudden death due to ischemic heart disease and how a wearable cardioverter- defibrillator vest can fill the gaps in risk, particularly, where an implantable defibrillator must be delayed or is not indicated. Key research is reviewed to present the clinical picture, and direct experience of the use of the wearable vest is presented in several case studies. INTENDED AUDIENCE Physicians, nurses, paramedics, emergency medical technicians (EMT) and other healthcare professionals who may treat patients presenting with acute MI. PURPOSE AND OVERALL GOAL This program introduces healthcare professionals to the use of the wearable cardioverter-defibrillator vest to fill gaps of high risk in which an implantable device is not indicated. OBJECTIVES This booklet is a collection of transcripts from multiple presenters at the CME lecture entitled, "Sudden Transitional Death Risk: When an ICD isn't the Answer", presented on November 11, 2006. Objectives for each presentation are contained within their respective sections of the booklet. FACULTY DISCLOSURE STATEMENT The authors/presenters of the sections contained herein have indicated that they have no financial arrangements or affiliations with any of the corporate organizations offering financial support or educational grants for this activity, with the exception of Dr. Tom Deering, who has received research grants, as has his institution, because of research done in association with Lifecor. Sudden Transitional Death Risk: When an ICD Isn't the Answer (CE for Nurses) Terminology ACE inhibitor (angiotensin-converting enzyme inhibitor): a class of drugs used in the treatment of hypertension and heart failure. Arrhythmogenic RV dysplasia: a right ventricular abnormality producing arrhythmia. Beta blocker: a class of drugs used to slow the heartbeat and treat hypertension. Brugada Syndrome: severe disturbances of the rhythm of the heart that can cause death. Cardiomyopathy: Primary myocardial disease, often of obscure or unknown etiology. Ejection fraction: A measure of ventricular contractility. Hypertrophic cardiomyopathy: A congenital heart disease that results in abnormal thickening of the ventricular septum and left ventricular wall. ICD: Implantable cardiac defibrillator. Revascularization: opening of the coronary arteries to blood flow. Stent: a small expandable mesh implant that holds open a coronary artery. Ventricular fibrillation (VF): A disorganised chaotic contraction of the ventricle that fails to effectively pump blood from the ventricle. Ventricular tachycardia (VT): Abnormal accelerated ventricular rhythm with a usual rate above 150 beats per minute. Sudden Transitional Death Risk: When an ICD Isn't the Answer (CE for Nurses) Section 1: Filling The Gaps In Our Utilization Of Defibrillators By Tom Deering, M.D. Electrophysiology and Arrhythmia Service, Piedmont Hospital, Atlanta, Georgia, USA INTRODUCTION This is a discussion about mortality issues and particularly sudden death, and what the role of the wearable defibrillator might be in preventing sudden death where gaps in utilization exist. PURPOSE AND OVERALL GOAL The purpose of this section is to offer data and experience on how the wearable defibrillator can fill gaps in utilization for patients subject to sudden death because of ischemic heart disease. OVERVIEW This section provides information on sudden cardiac death, government guidelines on implantable defibrillators and how the wearable defibrillator can bridge the gaps of utilization for some high risk groups. The material is organized around the following categories: Introduction Sudden Cardiac Death The Role for the Wearable Defibrillator High and Low Risk Groups Conclusion SECTION OBJECTIVES After completing this section of the activity the learner should be able to: Describe high and low risk groups for sudden ischemic death Describe government guidelines for implantable defibrillators Identify how the wearable defibrillator can bridge any gaps in risk Sudden Transitional Death Risk: When an ICD Isn't the Answer (CE for Nurses) Introduction This is a discussion about mortality issues and particularly sudden death, and what the role of the wearable defibrillator might be in this particular subject. First, it is important to put into perspective the importance of sudden mortality caused by cardiovascular events. We will then review the role of the ICD and the guidelines for its use. This will point out where gaps in utilization may exist, and suggest a potential role for the wearable defibrillator. <> Figure 1: U.S. Mortality Cardiovascular events and sudden death mortality are the leading cause of death in the United States, as you can see in Figure 1, and in Western Europe as well. <> Figure 2: Leading Causes of Death in the U.S Sudden Cardiac Death Fortunately, a close look at the management of cardiovascular mortality and sudden death shows that there are many steps that can be taken to improve the rates. In addition to general cardiac mortality, there is sudden death, indicated by the red in the Figure. <> Figure 3: Cardiac vs. Other Causes In fact, see Figure 3, you have to add up all non-cancer causes of death plus all cancer causes-- basically all other forms of death--in order to equal that of sudden cardiac death. So, it is a major public health issue. <> Figure 4: Arrhythmic Causes In the vast majority of studies, most sudden deaths are arrhythmic in origin, see Figure 4. This public dilemma offers an opportunity. We need to look at general medical interventions taken against cardiac problems and then the role of the ICD so we can see where this opportunity lies. A tiny percentage of the population is born with good genes and can live to be 100 and never take a medication. Fortunately, for the rest of the population, there are medicines to control blood pressure, to control cholesterol, and to treat other disorders. Even with all our medical interventions, there will still be sudden cardiovascular incidents, and for that we have the defibrillator--wearable, implantable, or external and hanging on the wall. <> Figure 5: Sudden Cardiac Death To review the initial studies using one of the old Myerburg slides, Figure 5, depicting the risk of sudden death in individual populations, the bigger risks are shown in the blue, that is, those who have survived an arrest and are prone to another, and in the green, those who have other high risk factors. The highest risk is for those with LV dysfunction and with a prior coronary event. Those high-risk populations are, of course the ones who were used for the initial studies of implantable defibrillators. Medical Interventions We also need to control the risk--with hypertensive medicines, cholesterol medicines, and other factors--using ACE inhibitors and beta-blockers. <> Figure 6: Primary Prevention Trials If you look at the TRACE and HOPE trials, Figure 6--those that used ACE inhibitors, and beta blockers--and you look at the incidence of sudden death, it has been reduced in these trials, Figure 7 below. <> Figure 7: SCD Reduction However, if you look at the red, you can see the total mortality and then compare to the blue, the sudden death mortality. You can see that about 50% of the total deaths are still sudden in origin. We may have brought down the overall mortality but there are still a large number of people dying suddenly. <> Figure 8: Secondary Prevention Trials The Role of the Defibrillator We need to develop ways to deal with sudden death mortality. That's where the role of the defibrillator has grown significantly. There are both secondary and primary prevention trials. In the secondary trials, the patient has already survived one incident. If you look at the three major trials, see Figure 8, you can see that there's been an overall reduction in the mortality rate and an overall reduction in death from arrhythmia, utilizing the defibrillator on an implantable basis. <> Figure 9: Primary Trials: Mortality The primary prevention trials have shown similar findings, see Figure 9. Conventional therapy is shown in the red, and trials with an implantable defibrillator in the blue. You see on the left the four major trials showing significant benefit: the significant p values, larger numbers of patients and the time of follow-up. On the right, you can see in the lighter colors, studies that did not show a significant benefit and these need to be discussed later. A number of ICDs are being implanted today, but more needs to be done. Government agencies, plus doctors of all specialties--primary care, cardiology, interventional, EP--in conjunction with the manufacturers--need to work together to promote the use of ICDs. <> Figure 10: Guidelines Government Guidelines What are the current ICD guidelines? Multiple guidelines have been issued over the years, but there is the most recent update, Figure 10. To simplify the guideline, for primary and secondary prophylactic therapy--ischemic and nonischemic patients are included--the patient should be on optimal medical therapy to lower the risk. The guidelines for secondary prophylaxis are straightforward: the patient needs to have suffered an event and survived. For primary prophylaxis it is a little more complex. The patient needs a low ejection fraction, II or III class heart failure, and for ischemics, no revascularization within three months or MI within 40 days. For non-ischemics, the patient also needs a time frame of rest, so the physician can see how responsive the myocardium will be to therapy and see if the situation will resolve. Collection of this data has been mandated by congress and is evaluated and watched in a registry so that over time more will be known. Role For The Wearable Defibrillator This brings us to the main topic: the transitional risk. Is there a role for the wearable defibrillator? Though the data are not clear yet, it appears there are five potential areas where there may be benefit. The guidelines are not perfectly clear on who should be given an implantable defibrillator. There is a gap between those who fall within these guidelines, and those who might benefit from a defibrillator but are not covered by the guidelines. The wearable defibrillator can bridge this gap for some high-risk patients. <> Figure 11: The Wearable Defibrillator LV Dysfunction First there are those who have LV dysfunction from an ischemic basis. Medicare requires 40 days post-infarction or three months postrevascularization. That is probably appropriate because in some patients you will have remodeling. <> Figure 12: CABG Patch Trial If we look at some of the older trials, such as the CABG-Patch trial, see Figure 12, there was no difference in survival after revascularization. <> Figure 13: MADIT II Trial Interestingly, if you look at the MADIT trial, Figure 13, and you look at the timedependence of risk based on revascularization--putting in a defibrillator within six months of revascularization--you can see that the defibrillator (shown in the blue) did not have a better survival rate. They were about equal. It didn't prove beneficial early on after revascularization. <> Figure 14: DINAMIT Trial Similarly, in the DINAMIT trial, Figure 14, there's no difference. There may have been an arrhythmic difference, but the overall mortality rates were no better. You can also look further at the non-ischemic cardiomyopathies. And if you have someone with a newly diagnosed myopathy, sometimes they progress and it doesn't resolve--sometimes they stay ill, and sometimes they get better. We need to treat them and study their progress over time. <> Figure 15: DEFNIITE Trial If you look at the DEFINITE trial, Figure 15, which studied non-ischemics, and you look at the two-year mortality rates, there was a tiny improvement with the defibrillator but it wasn't statistically significant, despite an improvement in sudden death rates. That study didn't show much benefit. <> Figure 16: SCD-HeFT Mortality Interestingly, if you look at the SCD-HeFT trial, Figure 16, and you carry it out to about 18 months, the graphs haven't separated--and this is a large trial with a mixture of about 50-50 ischemics and non-ischemics. Early Use Clearly there are problems with all of these trials: some of them are small, technology has advanced, and there is no question that we run into statistical and clinical issues of concern. However, the converse is not true. We have not proven that putting in an implanted defibrillator is effective early after an infarct, early after revascularization, or early in the stage of non-ischemic cardiomyopathy. So this is a gap where the use of a wearable device, for a short period of time, might be beneficial. Bridge to Transplant Another gap zone is the bridge to transplantation. If the transplant is years away, patient compliance with the inconvenience of the vest may become an issue. But if it's a question of several months, then certainly the patient can tolerate wearing the device. Reversible Cardiomyopathies Reversible, or possibly reversible cardiomyopathies, are another gap. For example, someone who has a cardiomyopathy due to hyperthyroidism or a viral illness. Or, commonly, a tachycardia-mediated cardiomyopathy due to atrial fibrillation, which may resolve with lowering the heart rate and/or re-establishing sinus rhythm. It makes little sense to implant a device in a patient who may only have a transient risk. Other Ongoing Medical Issues And then last, the wearable device may be appropriate for those who have other ongoing medical or cardiovascular issues--for instance, someone who is in the hospital, has non-sustained VT, has a known cardiomyopathy, but is being worked up for cancer and may not be a survivor. There is a gap there where the wearable device might be beneficial. So there are gaps in the guidelines between where the defibrillator is indicated and the defibrillator is not indicated, where there may be a role temporarily for a wearable device to protect these subgroups of patients. Contraindications There are some areas, of course, where there is a relative or absolute contraindication. Someone who has an infected ICD, for example, may not be a candidate. Or someone who has a big systemic infection, like a bad pneumonitis, or patients with an external dialysis catheter. <> Figure 17: Sudden Cardiac Death: Epidemiology Patients with arrhythmic risk There are also some uncommon cardiomyopathies that are associated with arrhythmic risk. When we looked at the curves from Myerburg's analyses earlier, see Figure 17, we focused on those areas that were exceptional. <> Figure 18: Individual Risk But remember, see Figure 18, the risk in an individual is very low, but the problem is that that is where most of the cardiovascular event rates and sudden death occur. So the risk individually is lower, but across the patient population it may be higher. Most of these are probably patients who are becoming ischemic, don't have a lot of risk factors, but are dying suddenly. But there are certain arrhythmic problems that exist in this group of patients that do pose a risk. <> Figure 19: Miscellaneous Cardiomyopathies There are also some miscellaneous cardiomyopathies, see Figure 19, like certain subgroups with a hypertrophic cardiomyopathy, arrhythmogenic RV dysplasia, certain neuromuscular disorders, or infiltrative cardiomyopathies. In addition, there are genetic disorders such as the Brugada syndrome, patients with the long or the short QT syndrome, those with catecholaminergic polymorphic VT, and those with idiopathic VF. These are patients in whom there might be arrhythmic risk. Not everybody with a hypertrophic cardiomyopathy needs a defibrillator, nor does everybody with Brugada's syndrome. But by the time the general cardiologist or internist sees it, discusses it with the patient, gets some ancillary studies, or gets it to the EP to manage it, a significant time lapse can occur. In the patient presenting with worrisome symptoms of uncommon cardiomyopathies, there may be a role for the use of the wearable defibrillator. So someone presenting to the physician with a Brugada EKG might be such a patient. High And Low Risk Groups Last are those patients of uncertain benefit. I think what happens is that there are patients in whom the risk of sudden death is quite low but we're still putting in implanted defibrillators. Let's look first at this low risk group. There are a number of well known markers of arrhythmic risk. And there are markers of autonomic dysfunction like baroreflex sensitivity and heart rate variability. There are electrophysiologic markers, like the level of ventricular ectopy, signal-averaged electrocardiography, inducible VT, T-wave alternans analysis. And then arrhythmic risk substrate markers, of which the most important marker has historically been left ventricular systolic dysfunction. <> Figure 20: LVEF Study If you note this LVEF study, the lower the ejection fraction, the greater the risk of sudden cardiac death. <> Figure 21: Primary Prevention Trials Now, Figure 21 is a controversial illustration because a number of disparate studies have been averaged together. In the red you can see conventional therapy, and in the blue, defibrillator therapy, and in the green, absolute risk reduction. But the indication is that there is an absolute risk reduction that keeps going down because we're expanding the envelope and making defibrillators more accessible. The people getting defibrillators today theoretically are at lower risk than the same general population before they were so readily available. Within all of these markers we've identified the highest risk group, but I think we have some people whose risk is now so low compared to, potentially, the longterm risk of the implanted device that we need to re-think the policy. <> Figure 22: TW Alternans Study Figure 22 shows a study by David Bloomfield this year: ischemic and nonischemic patients with an EF of 25% followed for a little over a year and a half. Red indicates it's positive or indeterminate and blue that it's negative. And you can see that if you have a negative T-wave alternans in this study, your risk was low. More data is needed, clearly, but there is a growing feeling that we can probably look at people within the high-risk group and identify some who are actually low-risk and maybe better choose our devices. Patient Needs Not everybody who is referred for a defibrillator should get one. Physicians need to have an honest discussion with their patients, talk about the risk-benefit ratio. I think in that scenario where you've got a patient who's waiting, there is role for a wearable device. High-Risk Groups Then there are the high-risk groups, patients with multiple co-morbidities or maybe the elderly. <> Figure 23: MADIT II Trial The MADIT II trial, Figure 23, compared renal function and mortality: the lower the glomerular filtration rate, the higher the mortality rate. Conventional therapy is shown in the blue, ICD in the green, and you can see that in this group with a GFR less than 35, there was no benefit to having the defibrillator. And that was a creatinine of 2.4. So there are subgroups that are quite ill with co-morbidities and may not benefit from a defibrillator. Again, though, there is a potential role for the wearable defibrillator, while other issues are being discussed and analyzed. I think what medicine has done is initially used implantable defibrillators on patients at very high risk and there were significant benefits, but the benefit to other patient populations is not as great. Our job as doctors is to balance that risk-benefit, to know the data, to have open and honest conversations with our patients. And in the meantime bear in mind that the wearable defibrillator is of possible benefit in certain high-risk groups. Conclusion to Section 1 The ICD is a wonderful device, and it saves many live. But there are other issues of risk to consider. And issues of the patient's individual decision, plus sometimes scheduling issues. There is a place for the wearable defibrillator. The conclusions are the following: 1. Sudden death remains an important clinical issue in the developed western world. 2. Pharmacologic therapy and ICD therapy have been instrumental in reducing the rates of sudden cardiac death. 3. The number needed to treat to save a life has decreased with broadening ICD indications 4. The wearable cardioverter- defibrillator may have a role in managing the gaps in the post-MI, post-revascularization patient, the person with a reversible cardiomyopathy, relative contraindications and the indecisive patient. It also may have a role in the patient who needs further risk stratification, where the benefit may not be clear, either too high or too low, or they have an uncommon cardiomyopathy that requires further evaluation and risk stratification. It is a complex issue to which there is no absolute answer, but there are gaps and there are transitional zones where a wearable defibrillator can be of great benefit. Section 2: Sudden Arrhythmic Death In CAD: The Magdeburg Approach By: Helmut Klein, MD. Director of Cardiology, University of Magdeburg Magdeburg, Germany INTRODUCTION This is a discussion about sudden arrhythmic death in coronary artery disease, and how this is approached in Magdeburg, Germany. PURPOSE AND OVERALL GOAL There is sufficient data to conclude that the risk of sudden death is reduced by an implantable defibrillator.The purpose of this section is to discuss bridging the transitory risk. OVERVIEW This section provides information on the use of the wearable defibrillator in Magdeburg based around detailed examination of several case studies. The material is organized around the following categories: Introduction The Wearable Defibrillator Case Studies The Magdeburg Experience Conclusion SECTION OBJECTIVES After completing this section of the activity the learner should be able to: Describe the transitory risk to ICD Discuss several case studies that show a wearable defibrillator helped bridge a transitory risk. Describe the overall statistics on the effectiveness of the wearable defibrillator in Magdeburg Introduction This part of the activity will discuss sudden arrhythmic death in coronary artery disease, and how this is approached in Magdeburg, Germany. There is sufficient evidence already to conclude that the permanent risk of sudden death, arrhythmic death, can be effectively reduced by the ICD. The best approach to bridge the transitory risk of sudden death is still a matter of debate. Transitory Risk Transitory risk remains the open question. As discussed above, according to the specific definition of the DINAMIT trial, the early phase means within the first 40 days. There's also a transitory risk in the peri-operative phase of the CABG-Patch, and other cardiac surgery with poor left ventricular ejection fraction--an ejection fraction of less than 30%. There are patients waiting for heart transplant who have a low ejection fraction who certainly have a much higher risk of dying suddenly. These are the major transitory risk patients, but we also have temporary inability to implant an ICD, systemic infection and co-morbidity preventing the ICD implant. Risk Stratification There is also the problem of risk stratification. There are patients that refuse to have an ICD implanted for various reasons. The solution for some of these patients is to have a wearable instead of an implanted device. In the era of early post-infarct revascularization, the overall mortality and the incidence of the cardiac arrest in these patients still is very unclear. No study in this patient population shows what the actual risk of sudden mortality is. Even if they are successfully revascularized, there are still a number of days of risk if patients remain with a low ejection fraction. But the number of these patients who die suddenly is still unknown. We also do not know what percentage of patients that present with an acute myocardial infarction, low ejection fraction, will really improve their dysfunction; specifically patients in the early phase of infarct with an election fraction below 30%. We have seen patients successfully implanted with one or two or more stents. The vessel is open but the patient still does not recover after the revascularization and remains at high risk of dying suddenly. Just revascularizing these patients does not completely remove the risk of death due to arrhythmia problems. Bridging Transitional Risk We need a tool to bridge the transitional risk to ICD--first of all to avoid unnecessary ICD implants. This has to do with quality of life and it also, certainly, entails a socioeconomic burden. Risk stratification, so far, has a low positive predictive accuracy. The ABCD trial may help, but there are only six centers in Germany-- a country of 82 million people-- where they do T-wave alternans studies. So risk stratification is still a matter of discussion. And antiarrhythmic drugs are relatively ineffective and fairly dangerous, specifically in the early phase of a myocardial infarction. What are the options to bridge this transitory risk? To remove the risk is very difficult. Even removing an aneurysm does not necessarily help these patients significantly. Studies show this does not reduce the risk of death from arrhythmic causes. One possibility is the wide distribution of automatic external defibrillators. This is certainly very helpful in public places and in hospitals. However, 75 to 80% of the patients having a high risk of dying suddenly will die at home. Even if you teach the family members to use it and convince them to buy an external defibrillator, the spouse may well be out shopping when the device is needed. The Wearable Defibrillator Another possibility is the wearable defibrillator, Figure 1. <> Figure 1: The Wearable Defibrillator This is not the very latest model, but it is the one being used in Germany with patients with ejection fraction of 30% or lower after an acute myocardial infarction. It includes back electrodes, front electrode, the battery and electronics, and the response buttons that can be used by the patient. <> Figure 2: Review Apparatus In Figure 2, you see the battery, the electronic circuits and the telephone modem which gives the physician the opportunity, via the Internet, to review the electrocardiograms of these patients once per week. <> Figure 3: Patient wearing Defibrillator Figure 3 shows a patient wearing the device. It is a device that is easy to put on and use. <> Figure 4: Training Session Figure 4 shows a training session. The patients who wear the device require training, which usually takes about one hour. The technician teaches the patient how to use the device, how to put it on, to recharge the battery every 24 hours, how to use the telephone modem, what to do when taking a shower, etc. The effectiveness of the wearable defibrillator is dependent upon good training, from the technician or even the physician. There is also a training movie that shows how to use it. Training is the key to the success of the wearable defibrillator: so that the patient is well informed on how to use the device. <> Figure 5: Reviewing the ECG Equally important, of course, Figure 5, is a doctor's ability, via the Internet, to look at the electrocardiogram. Either to control the appropriate wearing of the device or if the patient calls in and has had an alarm or has had a shock. The doctor can look at the ECG via the Internet to see what occurred. <> Figure 6: Stages of Operation Operation of the Defibrillator This chart, Figure 6, shows the stages of operation of the defibrillator. First there is initial detection of an event and confirmation. Then once the arrhythmia is identified there's a vibration alarm, there's a low tone warning, and there's a high volume tone warning. And, finally, if the arrhythmia is still going on, there is the gel deployment, there is a voice warning to bystanders not to touch the patient, and there comes the defibrillation shock. Altogether it takes about 30 seconds to deliver the shock. <> Figure 7: The Biphasic Waveform Initially when the ICD was developed it deployed only a monophasic shock, Figure 7. But now we have the varying biphasic waveform, according to the impedance, so the new biphasic waveform is the one that is in the wearable cardioverter defibrillator available today. Early Phase Use Now we will discuss use of the wearable defibrillator in the early phase after myocardial infarction. Which means that all of the patients that have come to the hospital and have a STEMI or non-STEMI myocardial infarction, with an ejection fraction of 30% or lower within the first 72 hours after myocardial infarction, receive the wearable defibrillator if they're mentally able to learn how to use it. They will keep the device for the next two or three months, in order to find out if their ejection fraction is improving after the acute phase of myocardial infarction. And if they are not improving, then it is time to consider the implantable defibrillator. But during this interim time, we want to protect these patients since they are sent home much earlier after revascularization than we did in earlier years. From the GISSI trial and others, we know there are patients who have developed ventricular tachycardia, ventricular fibrillation or a long lasting nonsustained ventricular tachycardia in the first two days after myocardial infarction. They have a higher risk of dying suddenly and these are also patients that receive the wearable defibrillator. Plus patients that come to the hospital in the very beginning in Killip class III or IV, which means they are in severe heart failure in the acute phase of myocardial infarction. Case Studies Case Study 1 We will now discuss three cases, which really reflect the efficacy of the wearable defibrillator in bridging the transitory risk. First is patient 1, a fifty-yearold female who presented in 2005 with an acute myocardial infarction, had a new left bundle branch block, positive troponin, two times syncope. She was in Killip class III and six hours after the beginning of chest pain, she came to the hospital, got a stent in the LAD. It was single vessel disease. The echo showed an ejection fraction of less than 25%. <> Figure 8: Case 1 Initial ECG Figure 8 shows the electrocardiogram for case 1 and as you can clearly see, there is a huge anterior myocardial infarction. <> Figure 9: Case 1 ECG after several days Figure 9 shows her ECG a few days later, and you can still see the remainders. There is scar tissue all over the anterior-inferior wall and this explains why this patient will have, over the next months, a risk of dying suddenly that is higher than the ones that we do revascularize but end up with a better ejection fraction. <> Figure 10: Case 1 ECG after several days Figure 10 shows the woman's ECG after three weeks. She was sleeping and in the middle of the night, after these extrasystoles, the device triggered because ventricular fibrillation occurred. After about 33 or 35 seconds, her husband lying next to her noticed that she just kind of jumped up; the alarm of course went off earlier. Without the device, she would have been found dead the next morning, without her husband knowing that this had occurred. This is a typical example of about 30 seconds and then the wearable defibrillator triggered and resuscitated her, it prevented her from dying. Now she is doing fine after one and a half years. Case Study 2 The second case is a 68-year-old male, with inferior myocardial infarction. This occurred 11 years ago. In the same year he had CABG bypass surgery and was fine until August of this year. So, he lasted 11 years as New York class I, no angina, and the ejection fraction is unknown. But in August this year he showed up in the hospital with an acute anterior myocardial infarction and at that time he was already in cardiogenic shock. The LAD was occluded, physicians had to insert an intra-aortic balloon pump. The ejection fraction, measured one day afterward, was about 20%. In the early phase, two stents were implanted, in the LAD and since he has had bypass surgery--probably the reason he went into cardiogenic shock after the graft to the right coronary artery was occluded--another stent was put in the right coronary artery, the RCA graft. The patient recovered from the cardiogenic shock. The wearable defibrillator was given to him after the third day in the hospital. Two weeks later he was discharged home. <> Figure 11: Case 2 ECG during MI Figure 11 shows Case 2's electrocardiogram during the acute phase of myocardial infarction. You can clearly see this is a large anterior myocardial infarction. What made him go into cardiogenic shock isn't known. He kept the wearable defibrillator, and after 2.5 months, again in the middle of the night, the wearable defibrillator recorded the following, Figure 12. <> Figure 12: Case 2 ECG after 2.5 months This ECG shows a sinus rhythm and then, all of a sudden, the onset of very rapid ventricular tachycardia. This went on for about ten minutes. <> Figure 13: Case 2 ECG, after walking Figure 13 shows the next ten minutes. As soon as the device detected the arrhythmia he woke up from sleep and pushed the response buttons. The device withheld the shock because he was conscious. We taught him not to release the buttons as long as he was conscious. He just pushed the buttons continuously for ten minutes while his wife called the EMT. When the EMT came, he was still conscious. <> Figure 14: Case 2 ECG, after amiodarone The EMTs gave him a shot of amiodarone, 150 mg, and then the arrhythmia stopped, see Figure 14. It terminated spontaneously. So he had this arrhythmia going on while being continuously conscious for about ten to fifteen minutes until the emergency workers came. If he had fallen unconscious, the device would have shocked him out of this arrhythmia. The device saved his life by keeping him alive until the emergency crew showed up. Case Study 3 The third case is a 77-year-old male who came into the hospital in October with an acute myocardial infarction. He was already in New York class III. His coronary angiography showed occluded LAD, the circumflex artery almost occluded, and he had an ejection fraction of 15%. A stent was put into the LAD and circumflex artery and he received the wearable defibrillator after the second day in the hospital. Five days after the acute myocardial infarction, he was put into a normal ward. Because of his age, he couldn't be sent home immediately. Five days after the acute myocardial infarction, he received two shocks from his wearable defibrillator. It shocked him out of ventricular tachycardia but he ended up being in severe heart failure and died six days later, six days after this VT event occurred. <> Figure 15: Case 3 ECG, on admission Figure 15 shows case 3 in the acute phase of myocardial infarction: right bundle branch block configuration with huge myocardial, anterior myocardial infarction. <> Figure 16: Case 3 ECG, after five days Figure 16 shows his ECG later. The ECG did not get the onset of the arrhythmia, but, again, it was a very rapid ventricular tachycardia that was hemodynamically ineffective that means he was very woozy and he became unconscious. <> Figure 17: Case 3 ECG, during shock Figure 17 shows that the device shocked him out of very rapid ventricular tachycardia. Without the device, he would've been found dead in the ward by the nurse during the night. But unfortunately he was so sick that he died later due to heart failure. Post-Op Patients Patients early post-op have a higher risk of dying suddenly--specifically the ones who have a bypass surgery, and show a low ejection fraction of 30% or less. If ventricular function does not improve after bypass surgery or even valve surgery, within the early phase, the first six days, our unit tends to give them the wearable defibrillator. Specifically, if they have non-sustained VT episodes in the intensive care unit it is felt that that these patient need protection for the next one or two months in order to become what could be called the MADIT II criteria patients. Even if they have had revascularized ventricles they still are at high risk. <> Figure 18: Post-Op Patient Figure 18 shows the ECG of a 56-year-old female and, again, the device is able, until the patient becomes unconscious, to withhold the shock. You can see here the onset of the arrhythmia. It goes on for a minute or two, and the patient then presses the button and the device withholds the shock because she was still conscious. Then the arrhythmia stopped spontaneously and the patient did not receive a shock. So the possibility of withholding the shock with this device seems to be very important. The Magdeburg Experience With The Wearable Defibrillator At Magdeburg we have had considerable experience with the wearable defibrillator. It has been used with 131 patients, 26 of them females. The mean ejection fraction was 26%. The mean duration of use was 95 days. Some patients had it only for a few days but these were not the ones post-myocardial infarction. One patient still wears the defibrillator after more than three and a half years. She's a circus artist with long QT syndrome and since she has type III long QT syndrome, she completely refused an implant. Doing these tricks in the circus on the trapeze she did not want to have the defibrillator implanted. But when she is at home, at rest, or she's sleeping, she has a tremendous number of VT, non-sustained torsades episodes. She loves the device and she refuses to have an implantable device until she stops performing in the circus. Leaving this one case aside, the maximum was 39 months: that was a patient awaiting a heart transplant. <> Figure 19: Inclusion Criteria Figure 19 shows the inclusion criteria at Magdeburg for a wearable defibrillator. There were 72 patients with post-myocardial infarction, we have 26 patients post-CABG, and we have 15 on the transplant waiting list. For other there are various reasons, specifically, the risk identification in patients that have had syncope. If they have a Brugada or long QT or other inherent arrhythmia risk, we give them a wearable device, until we find out if the patients are safe or need an implantable defibrillator. The majority are the ones that have had an acute myocardial infarction with a low ejection fraction. <> Figure 20: Results Results Figure 20 summarizes our experience from these 131 patients: four patients died, two of non-sudden cardiac deaths, two of sudden cardiac deaths without the wearable defibrillator-- they either refused to use it or took it off. One took it off because he wanted to take a shower but after the shower he thought he didn't need the device anymore and after a few hours he died due to arrhythmic causes. There are seven patients in the group that later on received heart transplantation. The results of the Magdeburg experience: 11 appropriate shocks in eight patients, three that clearly showed ventricular fibrillation and five showed very rapid hemodynamically ineffective ventricular tachycardia. And non-sustained VT in two-thirds of our patients detected by the Internet. After three months, twenty-seven out of 98 patients received the ICD implantation in the group of post-MI patients, the CABG patients. The risk stratification of four out of 15 and the heart transplant 13 out of 15, then received heart transplant. Some False Alarms Of course there were a few complications. There were false alarms due to oversensing, though this is much better in the recent device than the earlier devices. The electrodes are much better. There is less noise, which causes fewer inappropriate alarms--- not shocks, only alarms. If the patient moves in the back with these electrodes on you can have these false alarms, but there was never a false shock except in one patient. That was a 75 year-old lady walking on crutches after orthopedic surgery. When the alarms went off she couldn't put aside the crutches and she got a shock. That's the only one that got a shock, an inappropriate shock from noise due to electrode movement on the skin. And we have had three other inappropriate shocks that were not due to noise. There was one episode of ventricular fibrillation that was correctly detected by the device but, unfortunately, that was in a very early phase of the wearable defibrillator and the patient had put the electrode patches on the wrong side so it could not effectively defibrillate. This cannot happen anymore because of a modification to the device. Conclusion To Section 2 In conclusion, the wearable cardioverter defibrillator is an effective approach to protect patients who have a transitory risk of dying suddenly until definitive risk stratification has been performed, or the risk of ventricular tachycardia and ventricular fibrillation occurrence has definitely decreased. The wearable defibrillator is a safe and reliable tool to terminate ventricular tachycardia and ventricular fibrillation, has a tolerably low complication rate, and may contribute to reduced health care costs by preventing unnecessary ICD implants. Section 3: Risk of Sudden Death In Non-Ischemic Cardiomyopathy: A Question Of Timing. By: Leonard Ganz, MD, Director of the Electrophysiology Service, University of Pittsburgh, Pittsburgh, Pennsylvania, USA INTRODUCTION Based on a detailed case presentation of a patient with non-ischemic cardiomyopathy, this section discusses risk stratification for sudden death and the role of the wearable defibrillator. PURPOSE AND OVERALL GOAL The purpose of this section is to present evidence that an external defibrillator vest provides protection to patients during these waiting periods during which ICD implantations are proscribed OVERVIEW This section provides a case study of a patient with non-ischemic cardiomyopathy and discusses risk stratification for sudden death: Introduction Case Presentation The Risk Of Sudden Cardiac Death In Non-Ischemic Cardiomyopathy Conclusion SECTION OBJECTIVES After completing this section of the activity the learner should be able to: Describe one case and follow up that shows the benefits of a wearable defibrillator Discuss issues of risk stratification in non-ischemic cardiomyopathy. Introduction We will begin with a detailed case presentation of a patient with non-ischemic cardiomyopathy, and then discuss what we know about risk stratification for sudden death in non-ischemic cardiomyopathy. Case Presentation Patient A is a 59 year-old man who was admitted to a community hospital with a one-week history of progressive exertional dyspnea. He was very active; he regularly went on walks and over a week or so he found that he was getting increasingly breathless doing the same amount of activity that he usually did. He denied having chest pains, palpitations, syncope or near-syncope. Interestingly, he was told that he had a left bundle branch block about 30 years prior, which would have made him about 29. These records we're not available. He claims that he had a nuclear study at that time and it was normal. That would have been very early in the era of nuclear cardiology. The family history was non-contributory. He was taking no medications. He had quit smoking years before and drank alcohol in modest amounts. He said that he had had upper respiratory symptoms several weeks prior to his presentation. <> Figure 1: ECG Figure 1 shows Patient A's ECG. He did in fact have a very wide left bundle branch block pattern, and there was a prior history of left bundle branch block. He had an echocardiogram at the outside hospital, which showed a mildly enlarged LV with severe global hypokinesis and an ejection fraction estimated at 15 to 20%, a left ventricular end diastolic dimension of 6.7 cm, left atrial enlargement, and mild pulmonary hypertension. He was transferred to a tertiary care hospital where a coronary angiogram revealed normal coronary arteries. <> Figure 2: Left Ventriculogram Figure 2 shows his left ventriculogram in the ROA view. <> Figure 3: Telemetry And Figure 3 shows telemetry of his ECG. He had a lot of non-sustained VT on telemetry and a close inspection shows PVCs as well. <> Figure 4: More Telemetry But this patient had more than the usual share of monomorphic appearing VT, see Figure 4. This concerned his physicians. He had no prior history of syncope but the physicians were still concerned, due to the ambient ectopy. He had mild heart failure when he came in and after two doses of lasix his heart failure was almost resolved. He was started on an ACE inhibitor, carvedilol, and digoxin. Because the physicians were concerned, they elected to do a diagnostic electrophysiologic study. In a patient with non-ischemic cardiomyopathy, a diagnostic EP study is not always definitive. You will likely find either nothing or ventricular fibrillation. The likelihood of inducing monomorphic VT in a patient with non-ischemic cardiomyopathy is relatively low. He had a slightly prolonged H-P interval, a very wide QRS complex, but despite an aggressive stimulation protocol, no inducible VT or VF. Current guidelines preclude ICD implantation in a patient like this because he had just been diagnosed with a non-ischemic cardiomyopathy. A LifeVest was recommended as a bridge to an ICD when he could fulfill the implant criteria. It is not the hospital's standard practice to recommend wearable defibrillator vests in all patients with non-ischemic cardiomyopathy. It is a clinical judgment. The suggestion was rejected by his insurance company with the explanation that it was still only an investigational therapy. The hospital appealed twice and the second appeal was finally successful, so ultimately he was discharged with the wearable defibrillator vest five days later. <> Figure 5: Wearable Defibrillator Vest Figure 5 shows the type of vest he was provided. Follow up: Patient A Two weeks after he was discharged from the hospital he had to go to the emergency room. His wife was awakened by an audible signal from the LifeVest that essentially said to call 911. He was unaware of any problem although, on further questioning, said he was having an odd dream. The ER did not have the Internet information transmission set up yet. But the LifeVest was interrogated. These devices initially give you an audible signal-actually a vibration signal then an audible signal--so it takes longer for a LifeVest to deliver therapy than an implantable defibrillator. Electrophysiologists are accustomed to seeing patients in the office who have gotten a shock from their defibrillator. In the early age of defibrillators, this was equated with a life saved, but it is now known that many people get shocks from their defibrillators for non-sustained VT which would have been hemodynamically tolerated, or they get shocked from their defibrillator for a ventricular arrhythmia that would've stopped on its own and wouldn't have been life threatening. <> Figure 6: Interrogation of Patient A's Vest Information from the vest, Figure 6, is displayed in two channels. The top two lines are the same thing happening simultaneously. It shows a sinus rhythm with the patient's left bundle branch block. The patient develops a PVC and then a rapid polymorphic VT or a VF. It starts at about 18 seconds. He and his wife were in bed, and he didn't hear the audible signal to push the button. Then the vest went through all of its different alerts and the shock was delivered at about 58 seconds. We have a pretty good sense that this rhythm doesn't often stop on its own after 40 seconds. So it's fairly clear that this was a patient whose life was saved by the LifeVest. ICD Implantation Patient A had an ICD implanted the next day for secondary prevention. Now that he's survived a cardiac arrest, it's covered by all insurance companies. Two weeks after the implant the patient was able to host a high school graduation party for his twin son and daughter. At five-month follow-up, he'd had no ICD therapies. He's New York Heart Association class II on an ARB, carvedilol, spironolactone and digoxin. Six months after his initial presentation his ejection fraction has shown no improvement despite this medical therapy and, if anything, his ventricle has dilated further despite all of our best efforts. And he now has moderate mitral regurgitation that he didn't have before. The Risk Of Sudden Cardiac Death In Non-Ischemic Cardiomyopathy There are two clinical trials covering this. The DEFINITE and SCD-HeFT trials. DEFINITE did not achieve statistical significance but was a relatively small trial. SCD-HeFT did achieve statistical significance for the overall population but when you break the data down to just the non-ischemics, it didn't quite reach statistical significance. Nevertheless, taking this data together, CMS issued a national coverage decision, which initially allowed ICD implantation for patients with non-ischemic cardiomyopathy and ejection fraction less than or equal to 35%, but nine months after the initial presentation, three months if the patient was enrolled in a registry. Since all of our Medicare patients receiving prophylactic ICDs are enrolled in the ICD registry, patients may be implanted three months after the diagnosis of non-ischemic cardiomyopathy. When we're looking at a patient with newly diagnosed non-ischemic cardiomyopathy, that patient can fall into one of three categories. 1. Recent Onset It may be that the cardiomyopathy is really of recent onset and potentially reversible. And those conditions that might be reversible include myocarditis, peripartum cardiomyopathy, and tachycardia-induced cardiomyopathy. And these may all improve. There are really no data that suggest that if the LV recovers, the risk of sudden death is eliminated. The concern is the transition periods in which you have active remodeling, either for the better or for the worse with stretch fibrosis, remodeling may be associated with a higher acute risk. 2. Recent diagnosis It may also just be a cardiomyopathy of recent diagnosis. Which would mean that it has been in existence for a while but only recently discovered. Patient A, for example, had a history of symptoms over the previous week, and viral symptoms two weeks before. The fact that he had a chronic left bundle branch block and the fact that he was already dilated suggests that this could have been the acute recognition of a chronic problem. There have been some studies that have looked at markers of chronicity; these include a very poor ejection fraction, a dilated ventricle, RV dysfunction or an increased spherical shape to the LV. If patients have a chronic cardiomyopathy but are just recently diagnosed then they're at some baseline level of risk on the day that you meet them. And it's not clear whether improvement of the left ventricle ejection fraction with medical therapy necessarily mitigates or eliminates this risk. 3. Chronic Condition And the third possibility with a patient with cardiomyopathy, is that it is a truly chronic condition. The patient has had it for a long time, and may have documented poor ejection fraction for a long time, and those patients would be at their baseline level of risk. It's also possible, if they've already survived ten years, that they don't need a defibrillator, either internal or external. These patients fulfill criteria for getting an ICD but if they had had one put in ten years ago, or eight years ago, or five years ago, they could have done no better than they did without the device. New Data from the DEFINITE Trial There's some very intriguing data that's been published relatively recently from Alan Kadish and his colleagues of the DEFINITE study. Looking at timing, as it relates to non-ischemic cardiomyopathy and the risk of sudden death. In the DEFINITE trial there was no time prohibition for enrollment of patients in the trial. They didn't have to have an established cardiomyopathy for a certain period of time. But, the trial did ask investigators not to enroll patients with a reversible cardiomyopathy. So, they looked at the patients in the DEFINITE trial who were randomized to defibrillator or no defibrillator and then divided them by the time of diagnosis of cardiomyopathy to the time of randomization. And since the two cut points that CMS seemed to be interested in were three months and nine months, they did the analyses both ways. <> Figure 7: Probability of Survival, 3 Months Figure 7 shows these data looking at a diagnosis of non-ischemic cardiomyopathy for three months or less, or more than three months. They are Kaplan-Meir survival curves for the probability of survival, with the dark line for those with an ICD, and the dotted line for standard therapy. What this data shows is that the ICD seems to confer substantial survival benefit for the patients whose non-ischemic cardiomyopathy had been diagnosed less than three months prior to the time of randomization. But if they had been diagnosed more than three months earlier, if they had been randomized more than three months from the time of diagnosis, there wasn't much benefit. <> Figure 8: Probability of Survival, 9 Months Figure 8 shows the data with the cut point at nine months.The trend is the same. Those with an ICD show a strong trend towards an improved survival when patients were randomized nine months or less from the time of diagnosis, p value .058. Here again, if it's more than nine months, there doesn't seem to be any benefit. This is intriguing data. We don't know when these patients developed cardiomyopathy. Highest Risk Early This seems to suggest that the risk is highest early in these patients and the current CMS prohibition of implanting ICDs may result in a lot of these patients dying. This is the only trial data we have so far but the message is intriguing and very concerning. Whether these patients have a chronic cardiomyopathy and just recently came to attention because they developed heart failure or they have a new onset cardiomyopathy, the highest risk in these patients seems to be early. It is difficult to differentiate an acute cardiomyopathy, and in particular who might get better and who might not, or chronic cardiomyopathy. Regardless of the type of cardiomyopathy, we really don't have any data that tell us whether, when ventricular function gets better, the risk goes away, either in the long term or in that transitional risk period. The DEFINITE data suggests that the early period constitutes the most substantial risk for these patients. Conclusion to Section 3 An external defibrillator vest provides protection to patients during these waiting periods during which ICD implantations are proscribed. This is a great solution for patients who are in these gap periods who might have a substantial risk of sudden death. Some Further Issues What are the problems with the wearable defibrillator? First of all, the patients have to be taught that they are at a higher risk of dying suddenly. This is why we need protection for a short time. We have to tell the patient the implantable ICD itself is not without risk. And there is the socialeconomical-financial issue. The training and teaching period is extremely important. But with training, the acceptance is extremely good. I think it's the teaching issue that we have discovered in the last two or three years, that we have to do better. The bottom line is that with appropriate patient education the device is very acceptable to patients. Does this focus only on PCI Patients? It's just the acute PCI patient we've focused on here. These patients, they have their PCI and after the PCI they immediately get the device. So, patients come in with an acute myocardial infarction; they all get the acute PCI for acute myocardial infarction. The next two days we keep them either in the chest pain unit or in the normal ward and then we do the echo study and then we decide if they have an ejection fraction of 30% or lower we start to teach them to use the device and send them home with the device. Unfortunately, we were hoping that opening the vessel in those patients that come very early with a poor ejection fraction, that they would improve. But they do not. So there are a few studies that are contradicting studies. If you remember the Solomon study on the VALIANT trial that clearly showed that the highest risk, about 2.5% sudden death, in the first six weeks after myocardial infarction. There are other data. Then the curve goes very low and ends up being 2% per year in the chronic phase. On the other hand, data we coordinated for Finland showed completely the opposite: that gradually the longer you live, the risk of dying suddenly gets higher. So that is in favor of the implantable device. Then the other Solomon data, that was the enalopril study, shows that about 36% recover in the first ninety days after myocardial infarction. But there were also patients with ejection fractions of 55, even normal ejection fractions -- but of the ones that had ejection fractions below 55 %, only 36% recovered. There are 36% who recover, who probably have a low risk of dying suddenly, but the remainder, they still continue if we take ejection fraction as the most important risk factor. So I think the incidence of recovery is still unknown and these, the studies that exist, did not enroll patients with PCI treatment. The acute treatment of revascularization for acute myocardial infarction is up to interpretation. We don't know that. But I personally, I'm tremendously disappointed and would have had - would have hoped - that these patients would have recovered in higher percentages. Unfortunately, they do not do this. Are there studies planned to evaluate where the wearable cardioverter defibrillator can best be used? Yes, there is at least one study in collaboration with ZOLL and Lifecor. And that is looking at the early post-infarct period where we know that certain patients are at high risk for at least a certain time until they became eligible for implant. Or we have them in a stage where we have data that would suggest that the implantable defibrillator can improve survival and there's this obvious gap that for some people early post-infarct is a high risk period and we have no therapy for them. So it's an obvious potential use of the wearable defibrillator. Why do cardiac surgeons still insist on implanting ICDs in patients who are waiting for heart transplant? We know that the waiting period is quite long but I think even with six months the device implanted for only six months, or even a year, is far too expensive and also sometimes troublesome. You have the risk of infection. I think if the patient data shows, the cardiac surgeons would take a little bit more time and use their technicians to teach their patients on the waiting list to use the wearable device. It would certainly lower the cost of heart transplants significantly, specifically if the waiting time gets longer. The implantable ICD is not a solution to bridge this risk of waiting for heart transplant. I don't understand why they're not doing it.