ACC/AHA/ESC PRACTICE GUIDELINE
ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death—Executive Summary
A Report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death)
Developed in Collaboration With the European Heart Rhythm Association and the Heart Rhythm Society,
Douglas P. Zipes, MD, MACC, FAHA, FESC, Co-Chair, WRITING COMMITTEE MEMBER,
A. John Camm, MD, FACC, FAHA, FESC, Co-Chair, WRITING COMMITTEE MEMBER,
Martin Borggrefe, MD, FESC, WRITING COMMITTEE MEMBER,
Alfred E. Buxton, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
Bernard Chaitman, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
Martin Fromer, MD, WRITING COMMITTEE MEMBER,
Gabriel Gregoratos, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
George Klein, MD, FACC, WRITING COMMITTEE MEMBER,
Arthur J. Moss, MD, FACC, FAHA, WRITING COMMITTEE MEMBER
,
Robert J. Myerburg, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
Silvia G. Priori, MD, PhD, FESC, WRITING COMMITTEE MEMBER*,
Miguel A. Quinones, MD, FACC, WRITING COMMITTEE MEMBER,
Dan M. Roden, MD, CM, FACC, FAHA, WRITING COMMITTEE MEMBER,
Michael J. Silka, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
Cynthia Tracy, MD, FACC, FAHA, WRITING COMMITTEE MEMBER,
Sidney C. Smith, Jr, MD, FACC, FAHA, FESC, Chair, ACC/AHA TASK FORCE MEMBER,
Alice K. Jacobs, MD, FACC, FAHA, Vice-Chair, ACC/AHA TASK FORCE MEMBER,
Cynthia D. Adams, MSN, APRN-BC, FAHA, ACC/AHA TASK FORCE MEMBER,
Elliott M. Antman, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER
,
Jeffrey L. Anderson, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Sharon A. Hunt, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Jonathan L. Halperin, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Rick Nishimura, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Joseph P. Ornato, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Richard L. Page, MD, FACC, FAHA, ACC/AHA TASK FORCE MEMBER,
Barbara Riegel, DNSc, RN, FAHA, ACC/AHA TASK FORCE MEMBER,
Silvia G. Priori, MD, PhD, FESC, Chair, ESC COMMITTEE FOR PRACTICE GUIDELINES,
Jean-Jacques Blanc, MD, FESC, France, ESC COMMITTEE FOR PRACTICE GUIDELINESa,
Andrzej Budaj, MD, FESC, Poland, ESC COMMITTEE FOR PRACTICE GUIDELINESb,
A. John Camm, MD, FESC, FACC, FAHA, United Kingdom, ESC COMMITTEE FOR PRACTICE GUIDELINESc,
Veronica Dean, ESC COMMITTEE FOR PRACTICE GUIDELINESa,
Jaap W. Deckers, MD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESd,
Catherine Despres, ESC COMMITTEE FOR PRACTICE GUIDELINESa,
Kenneth Dickstein, MD, PhD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESe,
John Lekakis, MD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESf,
Keith McGregor, PhD, ESC COMMITTEE FOR PRACTICE GUIDELINESa,
Marco Metra, MD, ESC COMMITTEE FOR PRACTICE GUIDELINESg,
Joao Morais, MD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESh,
Ady Osterspey, MD, ESC COMMITTEE FOR PRACTICE GUIDELINESi,
Juan Luis Tamargo, MD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESj,
José Luis Zamorano, MD, FESC, ESC COMMITTEE FOR PRACTICE GUIDELINESj
a France
b Poland
c United Kingdom
d The Netherlands
e Norway
f Greece
g Italy
h Portugal
i Germany
j Spain
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Preamble
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It is important that the medical profession play a significant role in critically evaluating the use of diagnostic procedures and therapies as they are introduced and tested in the detection, management, or prevention of disease states. Rigorous and expert analysis of the available data documenting absolute and relative benefits and risks of those procedures and therapies can produce helpful guidelines that improve the effectiveness of care, optimize patient outcomes, and favorably affect the overall cost of care by focusing resources on the most effective strategies.
The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have jointly engaged in the production of such guidelines in the area of cardiovascular disease since 1980. The ACC/AHA Task Force on Practice Guidelines, whose charge is to develop, update, or revise practice guidelines for important cardiovascular diseases and procedures, directs this effort. The Task Force is pleased to have this guideline developed in conjunction with the European Society of Cardiology (ESC). Writing committees are charged with the task of performing an assessment of the evidence and acting as an independent group of authors to develop or update written recommendations for clinical practice.
Experts in the subject under consideration have been selected from all 3 organizations to examine subject-specific data and write guidelines. The process includes additional representatives from other medical practitioner and specialty groups when appropriate. Writing committees are specifically charged to perform a formal literature review, weigh the strength of evidence for or against a particular treatment or procedure, and include estimates of expected health outcomes where data exist. Patient-specific modifiers, comorbidities, and issues of patient preference that might influence the choice of particular tests or therapies are considered as well as frequency of follow-up and cost effectiveness. When available, information from studies on cost will be considered; however, review of data on efficacy and clinical outcomes will constitute the primary basis for preparing recommendations in these guidelines.
The ACC/AHA Task Force on Practice Guidelines and the ESC Committee for Practice Guidelines make every effort to avoid any actual, potential, or perceived conflict of interest that might arise as a result of an industry relationship or personal interest of the writing committee. Specifically, all members of the writing committee, as well as peer reviewers of the document, were asked to provide disclosure statements of all such relationships that might be perceived as real or potential conflicts of interest. Writing committee members are also strongly encouraged to declare a previous relationship with industry that might be perceived as relevant to guideline development. If a writing committee member develops a new relationship with industry during his or her tenure, he or she is required to notify guideline staff in writing. The continued participation of the writing committee member will be reviewed. These statements are reviewed by the parent task force, reported orally to all members of the writing committee at each meeting, and updated and reviewed by the writing committee as changes occur. Please refer to the methodology manuals for further description of the policies used in guideline development, including relationships with industry, which are available on the ACC, AHA, and ESC World Wide Web sites (http://www.acc.org/clinical/manual/manual_introltr.htm, http://circ.ahajournals.org/manual/, and http://www.escardio.org/knowledge/guidelines/Rules/, respectively). Please see Appendix 1 for author relationships with industry and Appendix 2 for peer reviewer relationships with industry that are pertinent to these guidelines.
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APPENDIX 1. Author Relationships With Industry for the ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death
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APPENDIX 2. External Peer Review Relationships With Industry for the ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death
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These practice guidelines are intended to assist health care providers in clinical decision making by describing a range of generally acceptable approaches for the diagnosis and management of specific diseases or conditions. These guidelines attempt to define practices that meet the needs of most patients in most circumstances. These guideline recommendations reflect a consensus of expert opinion after a thorough review of the available, current scientific evidence and are intended to improve patient care. If these guidelines are used as the basis for regulatory/payer decisions, the ultimate goal is quality of care and serving the patient’s best interests. The ultimate judgment regarding care of a particular patient must be made by the healthcare provider and the patient in light of all of the circumstances presented by that patient. There are circumstances in which deviations from these guidelines are appropriate.
The guidelines will be reviewed annually by the ACC/AHA Task Force on Practice Guidelines and the ESC Committee for Practice Guidelines and will be considered current unless they are updated, revised, or sunsetted and withdrawn from distribution. The executive summary and recommendations are published in the September 5, 2006 issue of the Journal of the American College of Cardiology, the September 5, 2006 issue of Circulation, and the September 17, 2006 issue of the European Heart Journal. The full-text guideline is e-published in the September 5, 2006 issue of the Journal of the American College of Cardiology, the September 5, 2006 issue of Circulation, and the September 2006 issue of Europace, as well as posted on the ACC (www.acc.org), AHA (www.americanheart.org), and ESC (www.escardio.org) World Wide Web sites. Copies of the full text and the executive summary are available from all 3 organizations.
Sidney C. Smith Jr., MD, FACC, FAHA, FESC, Chair, ACC/AHA Task Force on Practice Guidelines
Silvia G. Priori, MD, PhD, FESC, Chair, ESC Committee for Practice Guidelines
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I. Introduction
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Several excellent guidelines already exist on treating patients who have ventricular arrhythmias (Table 1). The purpose of this document is to update and combine the previously published recommendations into one source approved by the major cardiology organizations in the United States and Europe. We have consciously attempted to create a streamlined document, not a textbook that would be useful specifically to locate recommendations on the evaluation and treatment of patients who have or may be at risk for ventricular arrhythmias. Thus, sections on epidemiology, mechanisms and substrates, and clinical presentations are brief, because there are no recommendations for those sections. For the other sections, the wording has been kept to a minimum, and clinical presentations have been confined to those aspects relevant to forming recommendations.
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Table 1. Clinical Practice Guidelines and Policy Statements That Overlap With ACC/AHA/ESC Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of SCD
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The reader should note that the recommendations, text, figures, and tables included in this executive summary represent a succinct summary of the more extensive evidence base, critical evaluation, supporting text, tables, figures, and references that are included in the full-text guidelines. Readers are strongly encouraged to refer to the full-text guidelines.
The final recommendations for indications for a diagnostic procedure, a particular therapy, or an intervention for management of patients with ventricular arrhythmias and prevention of sudden cardiac death summarize both clinical evidence and expert opinion. Classification of Recommendations and Level of Evidence are expressed in the ACC/AHA/ESC format as follows: Classification of Recommendations
- • Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is beneficial, useful, and effective.
- • Class II: Conditions for which there is conflicting evidence and/or divergence of opinion about the usefulness/efficacy of a procedure or treatment.
- • Class IIa: Weight of evidence/opinion is in favor of usefulness/efficacy.
- • Class IIb: Usefulness/efficacy is less well established by evidence/opinion.
- • Class III: Conditions for which there is evidence and/or general agreement that a procedure/treatment is not useful/effective and in some cases may be harmful.
Level of Evidence
- • Level of Evidence A: Data derived from multiple randomized clinical trials or meta-analyses.
- • Level of Evidence B: Data derived from a single randomized trial or nonrandomized studies.
- • Level of Evidence C: Only consensus opinion of experts, case studies, or standard-of-care.
The schema for classification of recommendations and level of evidence is summarized in Table 2, which also illustrates how the grading system provides an estimate of the size of treatment effect and an estimate of the certainty of the treatment effect.
Recommendations with respect to therapy have considered:
- 1 The therapy to be offered (implantable cardioverter-defibrillator [ICD], antiarrhythmic drugs, surgery, and miscellaneous other treatments)
- 2 The point at which therapy is offered (primary prevention for those who are at risk but have not yet suffered from a life-threatening ventricular arrhythmia or sudden cardiac "death" episode, or secondary for those patients who have already experienced such arrhythmias or events),
- 3 The purpose of therapy (life preservation or symptom reduction/improved quality of life)
- 4 The etiology of the arrhythmia substrate (coronary heart disease, cardiomyopathy, or other conditions)
- 5 The functional status of the patient (New York Heart Association [NYHA] class)
- 6 The state of left ventricular (LV) function (left ventricular ejection fraction [LVEF]), and
- 7 The specific arrhythmia concerned (e.g., sustained monomorphic ventricular tachycardia [VT], polymorphic VT, and ventricular fibrillation [VF])
Not all therapeutic combinations are clinically relevant and many have no evidence base and probably will not have in the future because of the lack of clinical relevance or the relative rarity of the particular grouping. In many instances, the probable value of therapy may be reasonably inferred by the response of similar patients to specific therapies.
A. Prophylactic Implantable Cardioverter-Defibrillator Recommendations Across Published Guidelines.
The ACC/AHA/NASPE 2002 Guidelines Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices (1), the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (2), the ESC 2001 and 2003 Guidelines on Prevention of Sudden Cardiac Death (3,4), the ESC 2005 Guidelines for the Diagnosis and Treatment of Chronic Heart Failure (5) and the ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult (6) include a large number of recommendations on ICD therapy that merit attention.
Recommendations for prophylactic ICD implantation based on (EFs) have been inconsistent because clinical investigators have chosen different EFs for enrollment in trials of therapy, average values of the EF in such trials have been substantially lower than the cutoff value for enrollment, and subgroup analysis of clinical trial populations based on EF have not been consistent in their implications. Substantial differences among guidelines have resulted. However, no trial has randomized patients with an intermediate range of EFs. For instance, there is no trial that has specifically studied patients with a LVEF between 31% and 35%, and yet recommendations have been set for such patients on the basis of data derived from trials that studied groups with EFs less than or equal to 30%, others that enrolled patients with an EF less than or equal to 35%, and another that enrolled patients with an EF less than or equal to 40%. Recognizing these inconsistencies, this Guideline Writing Committee has decided to deal with the issue by constructing recommendations to apply to patients with an EF less than or equal to a range of values. The highest appropriate class of recommendation was then based on all trials that recruited patients with EFs within this range. In this way, potential conflicts between guidelines were reduced and errors due to drawing false conclusions relating to unstudied patient groups were minimized (see Table 3).
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Table 3. Inconsistencies Between ACC/AHA/ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of SCD and Other Published ACC/AHA and ESC Guidelines With Respect to ICD Therapy for Primary Prevention to Reduce Total Mortality by a Reduction in SCD
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It is important to note that experts can review the same data and arrive at different interpretations. Attempting to homogenize heterogeneous trials invariably leads to varying interpretations of the trial data. Furthermore, differences between the United States and Europe may modulate how recommendations are implemented. Guidelines are composed of recommendations on the basis of the best available medical science; however, implementation of these recommendations will be impacted by the financial, cultural, and societal differences among individual countries.
B. Classification of Ventricular Arrhythmias and Sudden Cardiac Death.
This classification table is provided for direction and introduction to the guidelines (Table 4).
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II. Incidence of sudden cardiac death
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The geographic incidence of sudden cardiac death (SCD) varies as a function of coronary heart disease (CHD) prevalence in different regions (3). Estimates for the United States (9–13) range from less than 200 000 to more than 450 000 SCDs annually, with the most widely used estimates in the range of 300 000 to 350 000 SCDs annually (14). The variation is based, in part, on the inclusion criteria used in individual studies. Overall, event rates in Europe are similar to those in the United States (3), with significant geographic variations reported.
The temporal definition of SCD strongly influences epidemiological data (15). The proportion of all natural deaths due to SCD is 13% when a definition of 1 h from onset of symptoms is used. In contrast, the community-wide study in Maastricht, the Netherlands, reported that 18.5% of all deaths were SCD, using a 24-h definition (16). The application of a 24-h definition of SCD increases the fraction of all natural deaths falling into the "sudden" category but reduces the proportion of all sudden natural deaths that are due to cardiac causes (15).
Approximately 50% of all CHD deaths are sudden and unexpected, occurring shortly (instantaneous to 1 h) after the onset of a change in clinical status, with some geographical variation in the fraction of coronary deaths that are sudden (17). The decreasing age-adjusted CHD mortality does not imply a decrease in absolute numbers of cardiac or SCDs (18,19) because of the growth and aging of the United States and European populations and the increasing prevalence of chronic heart disease (20).
Population Subgroups and Risk Prediction
Three factors affect the ability to identify subjects and population subgroups at risk and consideration of strategies for prevention of SCD:
- • The absolute numbers and event rates (incidence) among population subgroups (Fig. 1)
- • The clinical subgroups in which SCDs occur
- • The time-dependence of risk (14).
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Figure 1 Absolute numbers of events and event rates of SCD in the general population and in specific subpopulations over 1 y. General population refers to unselected population age greater than or equal to 35 y, and high-risk subgroups to those with multiple risk factors for a first coronary event. Clinical trials that include specific subpopulations of patients are shown in the right side of the figure. AVID = Antiarrhythmics Versus Implantable Defibrillators; CASH, Cardiac Arrest Study Hamburg; CIDS = Canadian Implantable Defibrillator Study; EF = ejection fraction; HF = heart failure; MADIT = Multicenter Automatic Defibrillator Implantation Trial; MI = myocardial infarction; MUSTT = Multicenter UnSustained Tachycardia Trial; SCD-HeFT = Sudden Cardiac Death in Heart Failure Trial. Modified with permission from Myerburg RJ, Kessler KM, Castellanos A. SCD. Structure, function, and time-dependence of risk. Circulation 1992;85:I2–10.
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The overall incidence of SCD in the United States is 1 to 2/1000 population (0.1% to 0.2%) per year, with some variations in estimates based on differences in various sources of data. This large population base includes those victims whose SCDs occur as a first cardiac event, as well as those whose SCDs can be predicted with greater accuracy because they are included in higher risk subgroups (Fig. 1). Higher levels of risk resolution can be achieved by identification of more specific subgroups. However, the corresponding absolute number of deaths becomes progressively smaller as the subgroups become more focused, limiting the potential impact of interventions to a much smaller fraction of the total population (21).
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III. Clinical presentations of patients with ventricular arrhythmias and sudden cardiac death
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Ventricular arrhythmias can occur in individuals with or without cardiac disorders. There is a great deal of overlap between clinical presentations (Table 5) and severity and type of heart disease. For example, stable and well-tolerated VT can occur in the individual with previous myocardial infarction (MI) and impaired ventricular function. The prognosis and management are individualized according to symptom burden and severity of underlying heart disease in addition to the clinical presentation.
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IV. Resting electrocardiography
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Recommendations
Class I
- Resting 12-lead electrocardiogram (ECG) is indicated in all patients who are evaluated for ventricular arrhythmias. (Level of Evidence: A)
A standard resting 12-lead ECG allows not only identification of various congenital abnormalities associated with ventricular arrhythmias and SCD (e.g., long QT syndrome [LQTS], short QT syndrome, Brugada syndrome, arrhythmogenic right ventricular [RV] cardiomyopathy) but also identification of various other ECG parameters, such as those due to electrolyte disturbances, or evidence suggesting underlying structural disease such as bundle-branch block, atrioventricular (AV) block, ventricular hypertrophy, and Q waves indicative of ischemic heart disease or infiltrative cardiomyopathy.
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V. Exercise testing
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Recommendations
Class I
- 1 Exercise testing is recommended in adult patients with ventricular arrhythmias who have an intermediate or greater probability of having CHD by age, gender, and symptoms* to provoke ischemic changes or ventricular arrhythmias. (Level of Evidence: B) *See Table 4 in the ACC/AHA 2002 Guideline Update for Exercise Testing (22) for further explanation of CHD probability.
- 2 Exercise testing, regardless of age, is useful in patients with known or suspected exercise-induced ventricular arrhythmias, including catecholaminergic VT to provoke the arrhythmia, achieve a diagnosis, and determine the patient’s response to tachycardia. (Level of Evidence: B)
Class IIa
- Exercise testing can be useful in evaluating response to medical or ablation therapy in patients with known exercise-induced ventricular arrhythmias. (Level of Evidence: B)
Class IIb
- 1 Exercise testing may be useful in patients with ventricular arrhythmias and a low probability of CHD by age, gender, and symptoms.* (Level of Evidence: C) *See Table 4 in the ACC/AHA 2002 Guideline Update for Exercise Testing (22) for further explanation of CHD probability.
- 2 Exercise testing may be useful in the investigation of isolated premature ventricular complexes (PVCs) in middle-aged or older patients without other evidence of CHD. (Level of Evidence: C)
Class III
- See Table 1 in the ACC/AHA 2002 Guideline Update for Exercise Testing (22) for contraindications. (Level of Evidence: B)
Exercise ECG is commonly used in the evaluation of patients with ventricular arrhythmias. Its most common application is for detection of silent ischemia in patients suspected of having underlying CHD (22). In patients with known or silent CHD or cardiomyopathies, the presence of frequent PVCs during or after exercise has been associated with greater risk for serious cardiovascular events but not specifically to SCD (23–25). However, exercise-induced PVCs in apparently normal individuals should not be used to dictate therapy unless associated with documented ischemia or sustained VT.
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VI. Ambulatory electrocardiography
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Recommendations
Class I
- 1 Ambulatory ECG is indicated when there is a need to clarify the diagnosis by detecting arrhythmias, QT-interval changes, T-wave alternans, or ST changes, to evaluate risk, or to judge therapy. (Level of Evidence: A)
- 2 Event monitors are indicated when symptoms are sporadic to establish whether they are caused by transient arrhythmias. (Level of Evidence: B)
- 3 Implantable recorders are useful in patients with sporadic symptoms suspected to be related to arrhythmias such as syncope when a symptom–rhythm correlation cannot be established by conventional diagnostic techniques. (Level of Evidence: B)
The use of continuous or intermittent ambulatory recording techniques can be very helpful in diagnosing a suspected arrhythmia, establishing its frequency and relating symptoms to the presence of the arrhythmia. Silent myocardial ischemic episodes may also be detected.
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VII. Electrocardiographic techniques and measurements
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Recommendations
Class IIa
- It is reasonable to use T-wave alternans for improving the diagnosis and risk stratification of patients with ventricular arrhythmias or who are at risk for developing life-threatening ventricular arrhythmias. (Level of Evidence: A)
Class IIb
- ECG techniques such as signal-averaged ECG, heart rate variability, baroflex sensitivity, and heart rate turbulence may be useful for improving the diagnosis and risk stratification of patients with ventricular arrhythmias or who are at risk of developing life-threatening ventricular arrhythmias. (Level of Evidence: B)
ICD trials, especially Multicenter Automatic Defibrillator Implantation Trial (MADIT) II, have highlighted the need to develop novel tools in order to identify patients at highest risk of ventricular arrhythmias and SCD. Numerous modalities exist at present for assessing this risk but only 2 are currently approved by the U.S. Food and Drug Administration: signal-averaged ECG and T-wave alternans. However, heart rate variability and baroflex sensitivity also show considerable promise.
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VIII. Left ventricular function and imaging
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Recommendations
Class I
- 1 Echocardiography is recommended in patients with ventricular arrhythmias who are suspected of having structural heart disease. (Level of Evidence: B)
- 2 Echocardiography is recommended for the subset of patients at high risk for development of serious ventricular arrhythmias or SCD, such as those with dilated, hypertrophic, or RV cardiomyopathies, acute MI survivors, or relatives of patients with inherited disorders associated with SCD. (Level of Evidence: B)
- 3 Exercise testing with an imaging modality (echocardiography or nuclear perfusion (single-photon emission computed tomography [SPECT]) is recommended to detect silent ischemia in patients with ventricular arrhythmias who have an intermediate probability of having CHD by age, symptoms, and gender and in whom ECG assessment is less reliable because of digoxin use, LV hypertrophy, greater than 1-mm ST-segment depression at rest, Wolff-Parkinson-White syndrome, or left bundle-branch block. (Level of Evidence: B)
- 4 Pharmacological stress testing with an imaging modality (echocardiography or myocardial perfusion SPECT) is recommended to detect silent ischemia in patients with ventricular arrhythmias who have an intermediate probability of having CHD by age, symptoms, and gender and are physically unable to perform a symptom-limited exercise test. (Level of Evidence: B)
Class IIa
- 1 Magnetic resonance imaging (MRI), cardiac computed tomography (CT), or radionuclide angiography can be useful in patients with ventricular arrhythmias when echocardiography does not provide accurate assessment of LV and RV function and/or evaluation of structural changes. (Level of Evidence: B)
- 2 Coronary angiography can be useful in establishing or excluding the presence of significant obstructive CHD in patients with life-threatening ventricular arrhythmias or in survivors of SCD, who have an intermediate or greater probability of having CHD by age, symptoms, and gender. (Level of Evidence: C)
- 3 LV imaging can be useful in patients undergoing biventricular pacing. (Level of Evidence: C)
A. Echocardiography.
Echocardiography is the imaging technique most commonly used because it is inexpensive in comparison with other techniques such as MRI and cardiac CT, is readily available, and provides accurate diagnosis of myocardial, valvular, and congenital heart disorders associated with ventricular arrhythmias and SCD (26,27) (Table 6). In addition, LV systolic function and regional wall motion can be evaluated, and in a majority of patients, EF can be determined (28).
B. Radionuclide Techniques.
Myocardial perfusion SPECT using exercise or pharmacological agents is applicable for a selected group of patients suspected of having ventricular arrhythmias triggered by ischemia and who are unable to exercise or have resting ECG abnormalities that limit the accuracy of ECG for ischemia detection.
C. Coronary Angiography.
In patients with life-threatening ventricular arrhythmias or in survivors of SCD, coronary angiography plays an important diagnostic role in establishing or excluding the presence of significant obstructive CHD.
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IX. Electrophysiological testing
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Electrophysiological (EP) testing with intracardiac recording and electrical stimulation at baseline and with drugs has been used for arrhythmia assessment and risk stratification for SCD. EP testing is used to document inducibility of VT, guide ablation, evaluate drug effects, assess the risks of recurrent VT or SCD, evaluate loss of consciousness in selected patients with arrhythmias suspected as a cause, and assess the indications for ICD therapy (29–32).
A. Electrophysiological Testing in Patients With Coronary Heart Disease.
Recommendations
Class I
- 1 EP testing is recommended for diagnostic evaluation of patients with remote MI with symptoms suggestive of ventricular tachyarrhythmias including palpitations, presyncope, and syncope. (Level of Evidence: B)
- 2 EP testing is recommended in patients with CHD to guide and assess efficacy of VT ablation. (Level of Evidence: B)
- 3 EP testing is useful in patients with CHD for the diagnostic evaluation of wide-QRS-complex tachycardias of unclear mechanism. (Level of Evidence: C)
Class IIa
- EP testing is reasonable for risk stratification in patients with remote MI, nonsustained VT, and LVEF equal to or less than 40%. (Level of Evidence: B)
Drug testing for assessing antiarrhythmic drug efficacy has largely been abandoned. The prognostic value of inducible ventricular flutter and fibrillation is still controversial. Limited data on the prognostic value of inducible ventricular flutter suggest that it may be an important end point (33,34).
B. Electrophysiological Testing in Patients With Syncope.
Recommendations
Class I
- EP testing is recommended in patients with syncope of unknown cause with impaired LV function or structural heart disease. (Level of Evidence: B)
Class IIa
- EP testing can be useful in patients with syncope when bradyarrhythmias or tachyarrhythmias are suspected and in whom noninvasive diagnostic studies are not conclusive. (Level of Evidence: B)
Syncope is a transient symptom that may be caused by an underlying rhythm disorder with or without an associated cardiac disease. EP testing is used to document or exclude the arrhythmic cause of syncope. It is most useful in patients with CHD and LV dysfunction. EP testing is usually not the first evaluation step but rather complementary to a full syncope work-up. Lack of correlation between symptoms and a documented arrhythmia elicited during EP testing may lead to overinterpretation or underinterpretation of the predictive value of the results. Transient drug effects that can provoke syncope may remain undetected. Other causes such as a neurological etiology need to be considered in some patients.
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X. Value of antiarrhythmic drugs
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Use of antiarrhythmic drugs in the acute setting is described in Section XIII on Acute Management of Specific Arrhythmias.
The available antiarrhythmic drugs can be classified by the Vaughan Williams 4-level schema (type I: fast sodium channel blockers, type II: beta blockers, type III: repolarization potassium current blockers, type IV: calcium channel antagonists) (35), or by the more mechanistic and clinically relevant Sicilian Gambit (36). The Vaughan Williams schema is somewhat outdated because antiarrhythmic drugs have complex actions that do not easily fit into 1 of the 4 specified classes of drug effects. This classification is of limited usefulness when choosing an antiarrhythmic drug to manage a specific arrhythmia. The Sicilian Gambit, introduced in 1991, was an attempt to provide a classification of antiarrhythmic drugs based on their mechanism of action and on arrhythmogenic mechanisms.
A. Beta Blockers.
These drugs are effective in suppressing ventricular ectopic beats and arrhythmias as well as reducing SCD in a spectrum of cardiac disorders in patients with and without heart failure (HF). Beta blockers are safe and effective antiarrhythmic agents that can be considered the mainstay of antiarrhythmic drug therapy (37,38).
B. Amiodarone and Sotalol.
The overall long-term survival benefit from amiodarone is controversial, with most studies showing no clear advantage over placebo. A few studies and one meta-analysis of several large studies have shown reduction in SCD using amiodarone for LV dysfunction due to prior MI and nonischemic dilated cardiomyopathy (DCM) (39–41), but the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) showed no survival benefit from amiodarone when compared with placebo (8,42).
Sotalol, like amiodarone, is effective in suppressing ventricular arrhythmias, but it has greater proarrhythmic effects and has not been shown to provide a clear increase in survival.
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XI. Special considerations where antiarrhythmic drugs may be indicated
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Amiodarone therapy may be considered in special situations (43); secondary subset analyses indicate possible survival benefit when amiodarone is combined with beta blockers (44,45).
A. Patients With Ventricular Tachyarrhythmias Who Do Not Meet Criteria for an Implantable Cardioverter-Defibrillator.
Beta blockers are the first-line therapy, but if this therapy at full therapeutic dose is not effective, then amiodarone or sotalol can be tried with monitoring for adverse effects during administration.
B. Patients With Implantable Cardioverter-Defibrillators Who Have Recurrent Ventricular Tachycardia/Ventricular Fibrillation With Frequent Appropriate Implantable Cardioverter-Defibrillator Firing.
This scenario, in its extreme, has been called defibrillator (tachycardia) storm, and it requires the addition of antiarrhythmic drugs and/or catheter ablation for control of the recurrent VT and associated ICD shocks. Sotalol is effective in suppressing atrial and ventricular arrhythmias (46), the combination of beta blockers and amiodarone is an alternative approach. Intravenous amiodarone has been useful.
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XII. Implantable and external cardioverter devices
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Several prospective multicenter clinical trials have documented improved survival with ICD therapy in high-risk patients with LV dysfunction due to prior MI and nonischemic cardiomyopathy (8,47–53) (Figure 2). ICD therapy compared with conventional or traditional antiarrhythmic drug therapy has been associated with mortality reductions from 23% to 55% depending on the risk group participating in the trial, with the improvement in survival due almost exclusively to a reduction in SCD. The trials may be subcategorized into 2 types: primary prevention (prophylactic) trials in which the subjects have not experienced a life-threatening ventricular arrhythmia or a symptomatic equivalent and secondary prevention trials involving subjects who have had an abortive cardiac arrest, a life-threatening VT, or unexplained syncope with work-up suggesting a high probability that a ventricular tachyarrhythmia was the cause of the syncope.
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Figure 2 Major implantable cardioverter-defibrillator (ICD) trials. Hazard ratios (vertical line) and 95% confidence intervals (horizontal lines) for death from any cause in the ICD group compared with the non-ICD group. *Includes only ICD and amiodarone patients from CASH. For expansion of trial names, see Appendix 3. CABG = coronary artery bypass graft surgery; EP = electrophysiological study; LVD = left ventricular dysfunction; LVEF = left ventricular ejection fraction; MI = myocardial infarction; N = number of patients; NICM = nonischemic cardiomyopathy; NSVT = nonsustained ventricular tachycardia; PVCs = premature ventricular complexes; SAECG = signal-averaged electrocardiogram.
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A. Automated External Defibrillator.
The automated external defibrillator (AED) saves lives when external defibrillation can be rendered within minutes of onset of VF. The AED represents an efficient method of delivering defibrillation to persons experiencing out-of-hospital cardiac arrest, and its use by both traditional and nontraditional first responders appears to be safe and effective (54,55). Appropriate device location to reduce time delay after onset of cardiac arrest is critical. Federal, state, and community efforts have been effective in placing AEDs in schools, sporting events, high-density residential sites, and airports as well as on airplanes and in police and fire department vehicles (56–58).
B. Ablation.
Recommendations
Class I
- 1 Ablation is indicated in patients who are otherwise at low risk for SCD and have sustained predominantly monomorphic VT that is drug resistant, who are drug intolerant, or who do not wish long-term drug therapy. (Level of Evidence: C)
- 2 Ablation is indicated in patients with bundle-branch reentrant VT. (Level of Evidence: C)
- 3 Ablation is indicated as adjunctive therapy in patients with an ICD who are receiving multiple shocks as a result of sustained VT that is not manageable by reprogramming or changing drug therapy or who do not wish long-term drug therapy (59,60). (Level of Evidence: C)
- 4 Ablation is indicated in patients with Wolff-Parkinson-White syndrome resuscitated from sudden cardiac arrest due to atrial fibrillation and rapid conduction over the accessory pathway causing VF (61). (Level of Evidence: B)
Class IIa
- 1 Ablation can be useful therapy in patients who are otherwise at low risk for SCD and have symptomatic nonsustained monomorphic VT that is drug resistant, who are drug intolerant, or who do not wish long-term drug therapy. (Level of Evidence: C)
- 2 Ablation can be useful therapy in patients who are otherwise at low risk for SCD and have frequent symptomatic predominantly mon
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Preamble
I. Introduction