© 2004 by European Society of Cardiology
ICD-implantation guidelines versus clinical practice: a prospective study of out-of-hospital cardiac arrest survivors*
Department of Cardiology, Academic Medical Center Amsterdam, The Netherlands
Manuscript submitted 11 June 2003. Accepted after revision 3 January 2004.
*Corresponding author. R.W. Koster, Academic Medical Center, Department of Cardiology, room F3-239, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. Tel.: +31-20-566-2608; fax: +31-20-566-6809. E-mail address: r.w.koster{at}amc.uva.nl (R.W. Koster).
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Abstract |
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AIMS: The aim of this study was prospectively to compare clinical practice of implantable cardioverter defibrillator (ICD) use with current guidelines in out-of-hospital cardiac arrest (OHCA) survivors.
METHODS AND RESULTS: From January 2000 till March 2002, 70 consecutive patients (pts) discharged from 15 hospitals after OHCA, with ventricular fibrillation (VF) as initial rhythm were included. Documentation of diagnosis, left ventricular function, ischaemia, electrophysiological studies (EPS), and decisions regarding ICD implantation were obtained from medical records. An expert committee compared these data with current guidelines. According to these guidelines 18 pts (26%) had an ICD indication and received an ICD while 37 pts (53%) had no indication and did not receive an ICD. In 13 pts without acute myocardial infarction insufficient diagnostic procedures were performed to permit a decision on ICD indication, hence no ICD was implanted. Two pts had an ICD indication but did not receive an ICD. During the follow-up with duration of 25 months (range 12–38 months), two sudden deaths occurred in the group of pts without an ICD. Of the pts with an ICD, 4 pts (22%) were reported to have received one or more shocks for VT/VF.
CONCLUSION: In at least 21% of OHCA survivors, insufficient diagnostic procedures concerning the indication for ICD implantation were performed or no ICD was implanted when indicated, despite clear guidelines. In particular, there was no proof of ischaemia prior to revascularization and no confirmation of the absence of ischaemia and EPS thereafter. Clinicians should be guided better in evaluating pts after OHCA concerning the indication for ICD implantation, especially when a transient of reversible condition was present or when treatment was sufficiently established safely to refrain from ICD implantation.
Key Words: implantable cardioverter defibrillator, guidelines, tachyarrhythmias, defibrillation, resuscitation
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Introduction |
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Survivors of out-of-hospital cardiac arrest (OHCA) are at high risk of recurrent cardiac arrest and sudden cardiac death, mainly due to recurrence of acute ventricular tachyarrhythmias, particularly ventricular fibrillation (VF) [1–
3]. Currently, the implantable cardioverter defibrillator (ICD) is the treatment of choice in secondary prevention of life-threatening ventricular tachyarrhythmias in survivors of OHCA [4–9].
Indications for ICD implantation have widened over the years and several European countries have recently adopted their first guidelines, including the Netherlands in 2000 [10], which include the management of survivors of OHCA.
We prospectively compared clinical practice of ICD implantation with the current guidelines, in a cohort of OHCA survivors in the Netherlands.
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Methods |
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Study population
The study was prospective and observational and comprised the city of Amsterdam and surrounding area, which included 885 km2 and 1.6 million inhabitants, served by 13 community hospitals and two academic hospitals. From January 2000 till March 2002, all patients with OHCA, identified by the emergency medical service (EMS) dispatch centre and with VF as initial rhythm, were followed from collapse. All patients who survived to hospital discharge were included.
Data collection
The continuous rhythm data from the automated external defibrillators and manual defibrillators were downloaded into a laptop on the scene. The rhythm data were analysed independently by a researcher and a physician, both experienced in rhythm analysis. VF was categorized as a disorganized rhythm, with a median amplitude of >100 µV.
Documentation concerning diagnosis, ischaemia, left ventricular function, electrophysiological studies (EPS), and decisions regarding ICD implantation was collected from medical records.
When a patient died during follow-up, the general practitioner was contacted for the date and cause of death. A year after inclusion of the last patient all were contacted to retrieve data on events and on shocks delivered by their ICDs.
Guidelines
Guidelines developed by the ACC/AHA [9], the European Society of Cardiology [8] and the Netherlands Society of Cardiology [10] were compared in order to create a protocol by which clinical practice could be evaluated. Indications as could be derived from the Madit-II study [11], were not incorporated in the study protocol as they were not part of the guidelines in the period we studied.
There are small differences in ICD implantation guidelines [12], but for patients with OHCA and documented VF as initial rhythm American, European and Dutch guidelines concurred. According to the guidelines during the study period, an ICD implantation was indicated in OHCA survivors with VF as initial rhythm when VF was not due to a transient, reversible, or treatable cause. An ICD was not indicated if the patient did not fit in one of these three criteria, had an expected lifetime of less than six months or had poor residual neurological function.
Some OHCA survivors in whom VF was due to an acute myocardial infarction (AMI) developed an ICD indication later on during hospital admission. These patients had non-sustained ventricular tachycardias (VT) at least four days after myocardial infarction, a left ventricular ejection fraction (LVEF) of 
40% and inducible VF or VT during EPS (criterion used in MUSTT [13] and part of the guidelines in use at the time of the study).
Classification of patients
Actual practice as derived from the medical records of each patient was compared with the guidelines by an expert committee, which included two cardiologists, of whom one was an electrophysiologist. Each patient was qualified as: "ICD indicated", "ICD not indicated" or "not enough diagnostic procedures performed to decide whether an ICD was indicated".
AMI was qualified as a transient cause of VF, i.e. no ICD indicated. To define AMI, we used the World Health Organisation definition [14,15].
Patients were classified as "not enough diagnostic procedures performed" if either no or insufficient diagnostic investigation or treatment was made after exclusion of AMI, or when revascularization was performed without documentation of ischaemia prior to treatment and lack of proof of absence of ischaemia or negative EPS after treatment.
Ethics
Medical ethics committees from participating hospitals approved the study. Informed consent was obtained from the patients post-resuscitation.
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Results |
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In the study period, 372 patients had an OHCA with VF as initial rhythm. Of these, 169 (45%) patients survived to admission, 98 patients died in the hospital and 70 (18%) patients were discharged from 18 different hospitals in the Netherlands. One patient was transferred to a hospital out of the country and not included in the analysis.
Of these 70 OHCA survivors 80% were males and the mean age was 63 years (range: 32–84 years). The classification of the patients concerning the ICD indication and the actual ICD implantation practice are shown in Fig. 1. Diagnoses of the 18 patients who did receive an ICD (mean age: 59 years, range: 34–76 years) and the diagnoses of the 52 patients who did not receive an ICD (mean age: 64 years, range: 32–84 years) are listed in Tables 1 and 2, respectively. In none of the eight revascularized patients, without an AMI, was ischaemia proven prior to treatment and in only one absence of ischaemia after revascularization was documented. Furthermore, in none of these patients EPS was performed after revascularization. In five patients no attempt at all to evaluate the cause of cardiac arrest was made.
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During the follow-up of median 25 months (range: 12–38 months), 13 patients died (19%). One patient with an ICD died; the ICD was turned off because of terminal renal failure in this patient who declined further treatment. All other deaths occurred in the patients without ICDs. Two of these 12 deaths were acute and due to cardiac arrest; one patient had not received an ICD because the initial VF was caused by an AMI and one patient died who had chosen not to have an ICD implanted. Four of the 18 patients with an ICD (22%) reported that they had received one or more shocks.
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Discussion |
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This study describes the management of patients who survived OHCA caused by VF, as a prospective inception cohort observed from the moment of the cardiac arrest. The cohort therefore is free from selection bias and referral bias to secondary or tertiary centres. We show that a large percentage of survivors of OHCA, are incompletely evaluated or not evaluated at all for the indication of ICD implantation. As it is convincingly proven that this therapy contributes to long-term survival in these high-risk patients, such a potentially important therapeutic opportunity is being withheld.
There are several important elements in this observation. First, although the guidelines are clear in the formulation of the indication of ICD implantation after OHCA for non-transient, non-reversible or non-treatable conditions, they all fail to define when these conditions are met. Conversely, it is not clear when the opposite is true: when the condition (mostly ischaemia) is adequately treated or when the condition can safely be considered transient. It is therefore not surprising that the evaluation of the patients in our study was incomplete in many cases. Secondly, the most prevalent transient condition is acute myocardial infarction, assuming that VF was caused in the initial electrical unstable phase of several hours duration in which Ia and Ib arrhythmias occur [16]. The time frame for primary VF in the guidelines is 48 h after onset of AMI, which may well incorporate cases where VF is caused by other, less transient mechanisms. More important, the diagnosis of AMI in a patient who has been successfully resuscitated may be more difficult than that under normal conditions, when the WHO criteria with the triad of chest pain, evolving ECG changes, typical rise and fall of specific markers for necrosis are applied. Retrograde amnesia makes the recognition of the history of chest pain less reliable and the ECG shortly after resuscitation may show gross abnormalities, which may be from ischaemia, as a result of the cardiac arrest. Furthermore, repeated shocks may be required before a stable rhythm is achieved and the possible damage from these shocks could result in transient rise in markers for ischaemia, thus mimicking acute myocardial damage. The level of certainty, of the diagnosis of AMI and, thus, the transient nature of the cause of cardiac arrest, may be higher than justified. Thirdly, many patients in our study were revascularized after recovery from the circulatory arrest, either by PTCA or by CABG. The procedure was usually not preceded by documentation of ischaemia and rarely followed by proof that ischaemia was effectively treated. Such therapy may assume adequate treatment of ischaemia and may unwarrantedly lead to the belief that the "reversible" cause of the cardiac arrest has been adequately treated. One can consider an EPS before and after revascularization procedures, with the intent to treat the underlying presumed ischaemic cause of the initial VF. However, it is not clear if EPS can unequivocally identify those at continued high risk after revascularization.
Our patients without ICD are a good match for the patients in the AVID registry who were considered to have a transient or treatable cause of their cardiac arrest [17]. Our study was not designed and was not large enough to prove or disprove the correctness of the treatment decisions in our cohort for the long-term outcome, but indicates that the daily care of our post-resuscitation patients leaves room for a more formal, protocol-driven approach to their evaluation. Such protocols do not yet exist. Only when the evaluation of patients for success of treatment or for the transient character of the condition, which is believed to have caused the cardiac arrest, is standardized, can we study their long-term prognosis, compare them with the prognosis of patients who did receive an ICD and confirm that our choices were appropriate. Future guidelines should be clear in specifying such protocols.
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Limitations |
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It is possible that contra-indications or other reasons not to implant an ICD (e.g. insufficient knowledge of guidelines by physicians in charge of the patients, attitude of patients towards devices) were present in the 15 patients in whom insufficient diagnostic procedures concerning the indication for ICD implantation were performed or no ICD was implanted when indicated, but which were not apparent in the medical records. In general, in the period of our study the guidelines were well known and there were no financial constraints for this indication for ICD implantation.
Our study reflects the practice of a relatively large number of hospitals, including both community hospitals and academic hospitals, but is limited to the Netherlands. In the Netherlands the ICD implantation rate in the study period was 20–40/million [18,19], which is an average of the rates observed throughout Europe. This report reflects the practice in the years 2000–2002 during and after which the rates of ICD implantation tended to increase. This increase probably reflects the acceptance of newer indications based on clinical trials, which focus on indications other than those related to OHCA. It is, therefore, unlikely that management of our patient group has changed markedly since that time.
In conclusion, our study shows that evaluation of patients after OHCA is frequently incomplete and that there are no clear protocols for such evaluation. This applies in particular to the clear definition of transient, reversible or treatable causes of the cardiac arrest. There is a gap not only between science and guidelines, but also between guidelines and practice. Our observations suggest that this gap may be narrowed by specifying the guidelines in more detail, especially when defining the transient or treatable nature of the condition causing OHCA from VF.
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Footnotes |
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*This study was supported by a grant from the Netherlands Heart Foundation (grant 98.179).
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References |
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[1] Baum R, Alvarez H III, Cobb L. Survival after resuscitation from out-of-hospital ventricular fibrillation. Circulation 1974; 50: 1231–1235.
[2] Schaffer W and Cobb L. Recurrent ventricular fibrillation and modes of death in survivors of out-of-hospital ventricular fibrillation. N Engl J Med 1975; 293: 259–262.[Abstract]
[3] Myerburg RJ, Kessler K, Estes D, et al. Long-term survival after prehospital cardiac arrest: analysis of outcome during an eight year study. Circulation 1984; 70: 538–546.
[4] Priori S, Aliot E, Blomstrom-Lundqvist C, et al. Task force on sudden cardiac death of the European Society of Cardiology. Eur Heart J 2001; 22: 1374–1450.
[5] Connolly SJ, Gent M, Roberts RS, et al. Canadian Implantable Defibrillator Study (CIDS): a randomized trial of the implantable cardioverter defibrillator against amiodarone. Circulation 2000; 101: 1297–1302.
[6] Kuck K-H, Cappato R, Siebels J, et al. Randomized comparison of antiarrhythmic drug therapy with implantable defibrillators in patients resuscitated from cardiac arrest: the Cardiac Arrest Study Hamburg (CASH). Circulation 2000; 102: 748–754.
[7] The AVID investigators. A comparison of antiarrhythmic drug therapy with implantable defibrillators in patients resuscitated from near fatal ventricular arrhythmias. N Engl J Med 1997; 337: 1576–1583.
[8] Hauer R, Aliot E, Block M, et al. Indications for implantable cardioverter defibrillator (ICD) therapy. Study group on guidelines on ICDs of the working group on arrhythmias and the working group on cardiac pacing of the European Society of Cardiology. Eur Heart J 2001; 22: 1074–1081.
[9] Gregoratus G, Cheitlin M, Conill A, et al. ACC/AHA guidelines for implantation of cardiac pacemakers and antiarrhythmia devices: a report of the ACC/AHA task force on practice guidelines. J Am Coll Cardiol 1998; 31: 1175–1206 [Committee on Pacemaker Implantation].
[10] Schalij M, Blom N, Dijkman B, et al. Richtlijn ICD-implantaties 2000. Cardiologie 2001; 8: 52–66.
[11] Moss AJ, Zareba W, Hall WJ, et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med 2002; 346: 877–883.
[12] Steinbeck G. Evolution of implantable cardioverter defibrillator indications: comparison of guidelines in the United States and Europe. J Cardiovasc Electrophysiol 2002; 13: S96–S99.[Medline]
[13] Buxton A, Lee K, Fisher J, et al. A randomized study of the prevention of sudden death in patients with coronary artery disease. N Engl J Med 1999; 341: 1882–1890.
[14] Tunstall-Pedoe H, Kuulasmaa K, Amouyel P, et al. Myocardial infarction and coronary deaths in the World Health Organization MONICA project. Circulation 1994; 90: 583–612.
[15] Gillum R, Fortmann S, Prineas R, et al. International diagnostic criteria for acute myocardial infarction and acute stroke. Am Heart J 1984; 108: 150–158.[CrossRef][Web of Science][Medline]
[16] Kaplinsky E, Ogawa S, Balke C, et al. Two periods of early ventricular arrhythmia in the canine acute myocardial infarction model. Circulation 1979; 60: 397–403.
[17] Wyse D, Friedman P, Brodsky M, et al. Life-threatening ventricular arrhythmias due to transient or correctable causes: high risk for death in follow-up. J Am Coll Cardiol 2001; 38: 1718–1724.
[18] Seidl K and Jochen S. Geographic differences in implantable cardioverter defibrillator usage. J Cardiovasc Electrophysiol 2002; 13: S100–S105.[Medline]
[19] Camm A and Nisam S. The utilization of the implantable defibrillator—a European enigma. Eur Heart J 2000; 21: 1998–2004.
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