TY - JOUR
T1 - Microvolt T-wave alternans and the risk of death or sustained ventricular arrhythmias in patients with left ventricular dysfunction
AU - Bloomfield, Daniel M.
AU - Bigger, J. Thomas
AU - Steinman, Richard C.
AU - Namerow, Pearila B.
AU - Parides, Michael K.
AU - Curtis, Anne B.
AU - Kaufman, Elizabeth S.
AU - Davidenko, Jorge M.
AU - Shinn, Timothy S.
AU - Fontaine, John M.
N1 - Funding Information:
Supported by grants HL-64862 from the National Heart, Lung, and Blood Institute, 5 M01 RR-00645, Division of Research Resources, General Clinical Research Centers Program, National Institutes of Health, Bethesda, Maryland; a grant from the Doris Duke Charitable Foundation, New York, New York; and a grant from Cambridge Heart Inc., Bedford, Massachusetts. The initial funding for the pilot phase of this study came from Cambridge Heart Inc. (Bedford, Massachusetts), the manufacturer of the equipment used to measure MTWA. The majority of funding (>80%) for the multicenter phase of this study was supported by an R01 grant (HL-64862) from the National Heart, Lung, and Blood Institute of the National Institutes of Health. Overall, Cambridge Heart provided ∼10% of the funding for this study (the other ∼10% came from the Doris Duke Foundation). Dr. Bloomfield previously served as a consultant to Cambridge Heart when this technology was first being developed.
PY - 2006/1/17
Y1 - 2006/1/17
N2 - OBJECTIVES: This study hypothesized that microvolt T-wave alternans (MTWA) improves selection of patients for implantable cardioverter-defibrillator (ICD) prophylaxis, especially by identifying patients who are not likely to benefit. BACKGROUND: Many patients with left ventricular dysfunction are now eligible for prophylactic ICDs, but most eligible patients do not benefit; MTWA testing has been proposed to improve patient selection. METHODS: Our study was conducted at 11 clinical centers in the U.S. Patients were eligible if they had a left ventricular ejection fraction (LVEF) ≤0.40 and lacked a history of sustained ventricular arrhythmias; patients were excluded for atrial fibrillation, unstable coronary artery disease, or New York Heart Association functional class IV heart failure. Participants underwent an MTWA test and then were followed for about two years. The primary outcome was all-cause mortality or non-fatal sustained ventricular arrhythmias. RESULTS: Ischemic heart disease was present in 49%, mean LVEF was 0.25, and 66% had an abnormal MTWA test. During 20 ± 6 months of follow-up, 51 end points (40 deaths and 11 non-fatal sustained ventricular arrhythmias) occurred. Comparing patients with normal and abnormal MTWA tests, the hazard ratio for the primary end point was 6.5 at two years (95% confidence interval 2.4 to 18.1, p < 0.001). Survival of patients with normal MTWA tests was 97.5% at two years. The strong association between MTWA and the primary end point was similar in all subgroups tested. CONCLUSIONS: Among patients with heart disease and LVEF ≤0.40, MTWA can identify not only a high-risk group, but also a low-risk group unlikely to benefit from ICD prophylaxis.
AB - OBJECTIVES: This study hypothesized that microvolt T-wave alternans (MTWA) improves selection of patients for implantable cardioverter-defibrillator (ICD) prophylaxis, especially by identifying patients who are not likely to benefit. BACKGROUND: Many patients with left ventricular dysfunction are now eligible for prophylactic ICDs, but most eligible patients do not benefit; MTWA testing has been proposed to improve patient selection. METHODS: Our study was conducted at 11 clinical centers in the U.S. Patients were eligible if they had a left ventricular ejection fraction (LVEF) ≤0.40 and lacked a history of sustained ventricular arrhythmias; patients were excluded for atrial fibrillation, unstable coronary artery disease, or New York Heart Association functional class IV heart failure. Participants underwent an MTWA test and then were followed for about two years. The primary outcome was all-cause mortality or non-fatal sustained ventricular arrhythmias. RESULTS: Ischemic heart disease was present in 49%, mean LVEF was 0.25, and 66% had an abnormal MTWA test. During 20 ± 6 months of follow-up, 51 end points (40 deaths and 11 non-fatal sustained ventricular arrhythmias) occurred. Comparing patients with normal and abnormal MTWA tests, the hazard ratio for the primary end point was 6.5 at two years (95% confidence interval 2.4 to 18.1, p < 0.001). Survival of patients with normal MTWA tests was 97.5% at two years. The strong association between MTWA and the primary end point was similar in all subgroups tested. CONCLUSIONS: Among patients with heart disease and LVEF ≤0.40, MTWA can identify not only a high-risk group, but also a low-risk group unlikely to benefit from ICD prophylaxis.
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U2 - 10.1016/j.jacc.2005.11.026
DO - 10.1016/j.jacc.2005.11.026
M3 - Article
C2 - 16412877
AN - SCOPUS:30344466096
SN - 0735-1097
VL - 47
SP - 456
EP - 463
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 2
ER -