Can we alternate between T-wave alternans testing methods?

Abstract

Sudden cardiac death (SCD) caused by malignant ventricular tachyarrhythmias in the setting of left ventricular dysfunction is the most prevalent cause of death among adults in the industrialized world. 1 ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. J Am Coll Cardiol. 2006; 48: 247-346 Abstract Full Text Full Text PDF Scopus (1034) Google Scholar Over the last 15 years, several clinical trials have established the implantable cardioverter defibrillator (ICD) as a highly effective treatment for primary prevention of SCD. 2 Moss A.J. Hall W.J. Cannom D.S. et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. N Engl J Med. 1996; 335: 1933-1940 Crossref PubMed Scopus (3547) Google Scholar , 3 Moss A.J. Zareba W. Hall W.J. et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002; 346: 877-883 Crossref PubMed Scopus (5577) Google Scholar , 4 Kadish A. Dyer A. Daubert J.P. et al. Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) investigatorsProphylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med. 2004; 350: 2151-2158 Crossref PubMed Scopus (1638) Google Scholar , 5 Buxton A.E. Lee K.L. Fisher J.D. et al. Multicenter Unsustained Tachycardia trial investigatorsA randomized study of the prevention of sudden death in patients with coronary artery disease. N Engl J Med. 1999; 341: 1882-1890 Crossref PubMed Scopus (2194) Google Scholar , 6 Bardy G.H. Lee K.L. Mark D.B. et al. Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) investigatorsAmiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005; 352: 225-237 Crossref PubMed Scopus (5258) Google Scholar , 7 Bigger Jr, J.T. Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary-artery bypass graft surgery. N Engl J Med. 1997; 337: 1569-1575 Crossref PubMed Scopus (884) Google Scholar Although early primary prevention trials 2 Moss A.J. Hall W.J. Cannom D.S. et al. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. N Engl J Med. 1996; 335: 1933-1940 Crossref PubMed Scopus (3547) Google Scholar , 3 Moss A.J. Zareba W. Hall W.J. et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002; 346: 877-883 Crossref PubMed Scopus (5577) Google Scholar , 4 Kadish A. Dyer A. Daubert J.P. et al. Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) investigatorsProphylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med. 2004; 350: 2151-2158 Crossref PubMed Scopus (1638) Google Scholar , 5 Buxton A.E. Lee K.L. Fisher J.D. et al. Multicenter Unsustained Tachycardia trial investigatorsA randomized study of the prevention of sudden death in patients with coronary artery disease. N Engl J Med. 1999; 341: 1882-1890 Crossref PubMed Scopus (2194) Google Scholar , 6 Bardy G.H. Lee K.L. Mark D.B. et al. Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) investigatorsAmiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005; 352: 225-237 Crossref PubMed Scopus (5258) Google Scholar used an electrophysiological study (EPS) in addition to reduced left ventricular ejection fraction (LVEF) to identify patients at highest risk for SCD, more recent trials selected patients for ICD implant based on a reduced LVEF alone. 3 Moss A.J. Zareba W. Hall W.J. et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 2002; 346: 877-883 Crossref PubMed Scopus (5577) Google Scholar , 4 Kadish A. Dyer A. Daubert J.P. et al. Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) investigatorsProphylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med. 2004; 350: 2151-2158 Crossref PubMed Scopus (1638) Google Scholar , 7 Bigger Jr, J.T. Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary-artery bypass graft surgery. N Engl J Med. 1997; 337: 1569-1575 Crossref PubMed Scopus (884) Google Scholar These trials showed an improvement in mortality rates, but did so with relatively low therapeutic efficacy. Consequently, although current guidelines recommend ICDs in most patients with LVEF ≤ 0.35, the clinical and cost-effectiveness of ICDs would improve if the therapy were applied to patient populations with greater background risk for SCD. 8 Sanders G.D. Hlatky M.A. Owens D.K. Cost-effectiveness of implantable cardioverter-defibrillators. N Engl J Med. 2005; 353: 1471-1480 Crossref PubMed Scopus (440) Google Scholar