BACKGROUND: Previous studies have demonstrated that microvolt T-wave alternans (MTWA) testing is a robust predictor of ventricular tachyarrhythmias and sudden cardiac death (SCD) in at-risk patients. However, recent studies have suggested that MTWA testing is not as good a predictor of "appropriate" implantable cardioverter-defibrillator (ICD) therapy as it is a predictor of SCD in patients without ICDs. OBJECTIVE: To evaluate the utility of MTWA testing for SCD risk stratification in patients without ICDs. METHODS: Patient-level data were obtained from 5 prospective studies of MTWA testing in patients with no history of ventricular arrhythmia or SCD. In these studies, ICDs were implanted in only a minority of patients and patients with ICDs were excluded from the analysis. We conducted a pooled analysis and examined the 2-year risk for SCD based on the MTWA test result. RESULTS: The pooled cohort included 2883 patients. MTWA testing was positive in 856 (30%), negative in 1627 (56%), and indeterminate in 400 (14%) patients. Among patients with a left ventricular ejection fraction (LVEF) of ≤35%, annual SCD event rates were 4.0%, 0.9%, and 4.6% among groups with MTWA positive, negative, and indeterminate test results. The SCD rate was significantly lower among patients with a negative MTWA test result than in patients with either positive or indeterminate MTWA test results (P <.001 for both comparisons). In patients with an LVEF of >35%, annual SCD event rates were 3.0%, 0.3%, and 0.3% among the groups with MTWA positive, negative, and indeterminate test results. The SCD rate associated with a positive MTWA test result was significantly higher than that associated with either negative (P <.001) or indeterminate MTWA test results (P = .003). CONCLUSIONS: In patients without ICDs, MTWA testing is a powerful predictor of SCD. Among patients with an LVEF of ≤35%, a negative MTWA test result is associated with a low risk for SCD. Conversely, among patients with an LVEF of >35%, a positive MTWA test result identifies patients at significantly heightened SCD risk. These findings may have important implications for refining primary prevention ICD treatment algorithms.
BACKGROUND: Previous studies have demonstrated that microvolt T-wave alternans (MTWA) testing is a robust predictor of ventricular tachyarrhythmias and sudden cardiac death (SCD) in at-risk patients. However, recent studies have suggested that MTWA testing is not as good a predictor of "appropriate" implantable cardioverter-defibrillator (ICD) therapy as it is a predictor of SCD in patients without ICDs. OBJECTIVE: To evaluate the utility of MTWA testing for SCD risk stratification in patients without ICDs. METHODS:Patient-level data were obtained from 5 prospective studies of MTWA testing in patients with no history of ventricular arrhythmia or SCD. In these studies, ICDs were implanted in only a minority of patients and patients with ICDs were excluded from the analysis. We conducted a pooled analysis and examined the 2-year risk for SCD based on the MTWA test result. RESULTS: The pooled cohort included 2883 patients. MTWA testing was positive in 856 (30%), negative in 1627 (56%), and indeterminate in 400 (14%) patients. Among patients with a left ventricular ejection fraction (LVEF) of ≤35%, annual SCD event rates were 4.0%, 0.9%, and 4.6% among groups with MTWA positive, negative, and indeterminate test results. The SCD rate was significantly lower among patients with a negative MTWA test result than in patients with either positive or indeterminate MTWA test results (P <.001 for both comparisons). In patients with an LVEF of >35%, annual SCD event rates were 3.0%, 0.3%, and 0.3% among the groups with MTWA positive, negative, and indeterminate test results. The SCD rate associated with a positive MTWA test result was significantly higher than that associated with either negative (P <.001) or indeterminate MTWA test results (P = .003). CONCLUSIONS: In patients without ICDs, MTWA testing is a powerful predictor of SCD. Among patients with an LVEF of ≤35%, a negative MTWA test result is associated with a low risk for SCD. Conversely, among patients with an LVEF of >35%, a positive MTWA test result identifies patients at significantly heightened SCD risk. These findings may have important implications for refining primary prevention ICD treatment algorithms.
Authors: Daniel M Bloomfield; J Thomas Bigger; Richard C Steinman; Pearila B Namerow; Michael K Parides; Anne B Curtis; Elizabeth S Kaufman; Jorge M Davidenko; Timothy S Shinn; John M Fontaine Journal: J Am Coll Cardiol Date: 2005-12-15 Impact factor: 24.094
Authors: Arthur J Moss; Wojciech Zareba; W Jackson Hall; Helmut Klein; David J Wilber; David S Cannom; James P Daubert; Steven L Higgins; Mary W Brown; Mark L Andrews Journal: N Engl J Med Date: 2002-03-19 Impact factor: 91.245
Authors: Gust H Bardy; Kerry L Lee; Daniel B Mark; Jeanne E Poole; Douglas L Packer; Robin Boineau; Michael Domanski; Charles Troutman; Jill Anderson; George Johnson; Steven E McNulty; Nancy Clapp-Channing; Linda D Davidson-Ray; Elizabeth S Fraulo; Daniel P Fishbein; Richard M Luceri; John H Ip Journal: N Engl J Med Date: 2005-01-20 Impact factor: 91.245
Authors: Kenneth A Ellenbogen; Joseph H Levine; Ronald D Berger; James P Daubert; Stephen L Winters; Eugene Greenstein; Alaa Shalaby; Andi Schaechter; Haris Subacius; Alan Kadish Journal: Circulation Date: 2006-02-06 Impact factor: 29.690
Authors: Omid Sayadi; Faisal M Merchant; Dheeraj Puppala; Theofanie Mela; Jagmeet P Singh; E Kevin Heist; Chris Owen; Antonis A Armoundas Journal: Circ Arrhythm Electrophysiol Date: 2013-07-24