Evidence regarding clinical use of microvolt T-wave alternans
Background: Microvolt T-wave alternans (MTWA) testing in many studies has proven to be a highly accurate predictor of ventricular tachyarrhythmic events (VTEs) in patients with risk factors for sudden cardiac death (SCD) but without a prior history of sustained VTEs (primary prevention patients)....
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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Elsevier
2011
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| Online Access: | http://hdl.handle.net/1721.1/61763 https://orcid.org/0000-0002-5573-0137 |
| _version_ | 1811087355513143296 |
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| author | Hohnloser, Stefan H. Ikeda, Takanori Cohen, Richard J. |
| author2 | Harvard University--MIT Division of Health Sciences and Technology |
| author_facet | Harvard University--MIT Division of Health Sciences and Technology Hohnloser, Stefan H. Ikeda, Takanori Cohen, Richard J. |
| author_sort | Hohnloser, Stefan H. |
| collection | MIT |
| description | Background:
Microvolt T-wave alternans (MTWA) testing in many studies has proven to be a highly accurate predictor of ventricular tachyarrhythmic events (VTEs) in patients with risk factors for sudden cardiac death (SCD) but without a prior history of sustained VTEs (primary prevention patients). In some recent studies involving primary prevention patients with prophylactically implanted cardioverter-defibrillators (ICDs), MTWA has not performed as well.
Objective:
This study examined the hypothesis that MTWA is an accurate predictor of VTEs in primary prevention patients without implanted ICDs, but not of appropriate ICD therapy in such patients with implanted ICDs.
Methods:
This study identified prospective clinical trials evaluating MTWA measured using the spectral analytic method in primary prevention populations and analyzed studies in which: (1) few patients had implanted ICDs and as a result none or a small fraction (≤15%) of the reported end point VTEs were appropriate ICD therapies (low ICD group), or (2) many of the patients had implanted ICDs and the majority of the reported end point VTEs were appropriate ICD therapies (high ICD group).
Results:
In the low ICD group comprising 3,682 patients, the hazard ratio associated with a nonnegative versus negative MTWA test was 13.6 (95% confidence interval [CI] 8.5 to 30.4) and the annual event rate among the MTWA-negative patients was 0.3% (95% CI: 0.1% to 0.5%). In contrast, in the high ICD group comprising 2,234 patients, the hazard ratio was only 1.6 (95% CI: 1.2 to 2.1) and the annual event rate among the MTWA-negative patients was elevated to 5.4% (95% CI: 4.1% to 6.7%). In support of these findings, we analyzed published data from the Multicenter Automatic Defibrillator Trial II (MADIT II) and Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) trials and determined that in those trials only 32% of patients who received appropriate ICD therapy averted an SCD.
Conclusion:
This study found that MTWA testing using the spectral analytic method provides an accurate means of predicting VTEs in primary prevention patients without implanted ICDs; in particular, the event rate is very low among such patients with a negative MTWA test. In prospective trials of ICD therapy, the number of patients receiving appropriate ICD therapy greatly exceeds the number of patients who avert SCD as a result of ICD therapy. In trials involving patients with implanted ICDs, these excess appropriate ICD therapies seem to distribute randomly between MTWA-negative and MTWA-nonnegative patients, obscuring the predictive accuracy of MTWA for SCD. Appropriate ICD therapy is an unreliable surrogate end point for SCD. |
| first_indexed | 2024-09-23T13:44:46Z |
| format | Article |
| id | mit-1721.1/61763 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:44:46Z |
| publishDate | 2011 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/617632022-09-28T15:52:22Z Evidence regarding clinical use of microvolt T-wave alternans Hohnloser, Stefan H. Ikeda, Takanori Cohen, Richard J. Harvard University--MIT Division of Health Sciences and Technology Cohen, Richard J. Cohen, Richard J. Background: Microvolt T-wave alternans (MTWA) testing in many studies has proven to be a highly accurate predictor of ventricular tachyarrhythmic events (VTEs) in patients with risk factors for sudden cardiac death (SCD) but without a prior history of sustained VTEs (primary prevention patients). In some recent studies involving primary prevention patients with prophylactically implanted cardioverter-defibrillators (ICDs), MTWA has not performed as well. Objective: This study examined the hypothesis that MTWA is an accurate predictor of VTEs in primary prevention patients without implanted ICDs, but not of appropriate ICD therapy in such patients with implanted ICDs. Methods: This study identified prospective clinical trials evaluating MTWA measured using the spectral analytic method in primary prevention populations and analyzed studies in which: (1) few patients had implanted ICDs and as a result none or a small fraction (≤15%) of the reported end point VTEs were appropriate ICD therapies (low ICD group), or (2) many of the patients had implanted ICDs and the majority of the reported end point VTEs were appropriate ICD therapies (high ICD group). Results: In the low ICD group comprising 3,682 patients, the hazard ratio associated with a nonnegative versus negative MTWA test was 13.6 (95% confidence interval [CI] 8.5 to 30.4) and the annual event rate among the MTWA-negative patients was 0.3% (95% CI: 0.1% to 0.5%). In contrast, in the high ICD group comprising 2,234 patients, the hazard ratio was only 1.6 (95% CI: 1.2 to 2.1) and the annual event rate among the MTWA-negative patients was elevated to 5.4% (95% CI: 4.1% to 6.7%). In support of these findings, we analyzed published data from the Multicenter Automatic Defibrillator Trial II (MADIT II) and Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) trials and determined that in those trials only 32% of patients who received appropriate ICD therapy averted an SCD. Conclusion: This study found that MTWA testing using the spectral analytic method provides an accurate means of predicting VTEs in primary prevention patients without implanted ICDs; in particular, the event rate is very low among such patients with a negative MTWA test. In prospective trials of ICD therapy, the number of patients receiving appropriate ICD therapy greatly exceeds the number of patients who avert SCD as a result of ICD therapy. In trials involving patients with implanted ICDs, these excess appropriate ICD therapies seem to distribute randomly between MTWA-negative and MTWA-nonnegative patients, obscuring the predictive accuracy of MTWA for SCD. Appropriate ICD therapy is an unreliable surrogate end point for SCD. 2011-03-23T12:45:51Z 2011-03-23T12:45:51Z 2008-10 Article http://purl.org/eprint/type/JournalArticle 1547-5271 http://hdl.handle.net/1721.1/61763 Hohnloser, Stefan H., Takanori Ikeda, and Richard J. Cohen. “Evidence regarding clinical use of microvolt T-wave alternans.” Heart Rhythm 6.3, Supplement 1 (2009): S36-S44. https://orcid.org/0000-0002-5573-0137 en_US http://dx.doi.org/10.1016/j.hrthm.2008.10.011 Heart Rhythm Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ application/pdf Elsevier Prof. Cohen via Courtney Crummett |
| spellingShingle | Hohnloser, Stefan H. Ikeda, Takanori Cohen, Richard J. Evidence regarding clinical use of microvolt T-wave alternans |
| title | Evidence regarding clinical use of microvolt T-wave alternans |
| title_full | Evidence regarding clinical use of microvolt T-wave alternans |
| title_fullStr | Evidence regarding clinical use of microvolt T-wave alternans |
| title_full_unstemmed | Evidence regarding clinical use of microvolt T-wave alternans |
| title_short | Evidence regarding clinical use of microvolt T-wave alternans |
| title_sort | evidence regarding clinical use of microvolt t wave alternans |
| url | http://hdl.handle.net/1721.1/61763 https://orcid.org/0000-0002-5573-0137 |
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