Clinical utility of microvolt T-wave alternans testing in identifying patients at high or low risk of sudden cardiac death
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Author(s)
Merchant, Faisal M.
Ikeda, Takanori
Pedretti, Roberto F.E.
Salerno-Uriarte, Jorge A.
Chow, Theodore
Chan, Paul S.
Bartone, Cheryl
Hohnloser, Stefan H.
Cohen, Richard J.
Armoundas, Antonis A.
Date Issued
March 2012
Journal
Heart Rhythm
Publisher
Elsevier
Citation
Merchant, Faisal M., Takanori Ikeda, Roberto F.E. Pedretti, Jorge A. Salerno-Uriarte, Theodore Chow, Paul S. Chan, Cheryl Bartone, Stefan H. Hohnloser, Richard J. Cohen, and Antonis A. Armoundas. “Clinical Utility of Microvolt T-Wave Alternans Testing in Identifying Patients at High or Low Risk of Sudden Cardiac Death.” Heart Rhythm 9, no. 8 (August 2012): 1256–1264.e2.
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Author's final manuscript
Abstract
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.
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.
MIT Department
Institute for Medical Engineering and Science
Harvard University--MIT Division of Health Sciences and Technology
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DOI of Published Version
https://doi.org/10.1016/j.hrthm.2012.03.014
