Exner Derek V, Kavanagh Katherine M, Slawnych Michael P, Mitchell L Brent, Ramadan Darlene, Aggarwal Sandeep G, Noullett Catherine, Van Schaik Allie, Mitchell Ryan T, Shibata Mariko A, Gulamhussein Sajad, McMeekin James, Tymchak Wayne, Schnell Gregory, Gillis Anne M, Sheldon Robert S, Fick Gordon H, Duff Henry J
Libin Cardiovascular Institute of Alberta, Calgary, Canada; Department of Community Health Sciences, University of Calgary, Calgary, Canada.
J Am Coll Cardiol. 2007 Dec 11;50(24):2275-84. doi: 10.1016/j.jacc.2007.08.042. Epub 2007 Nov 26.
This study sought to determine whether combined assessment of autonomic tone plus cardiac electrical substrate identifies most patients at risk of serious events after myocardial infarction (MI) and to compare assessment at 2 to 4 weeks versus 10 to 14 weeks after MI.
Methods to identify most patients at risk of serious events after MI are required.
Patients (n = 322) with an ejection fraction (EF) <0.50 in the initial week after MI were followed up for a median of 47 months. Serial assessment of autonomic tone, including heart rate turbulence (HRT), electrical substrate, including T-wave alternans (TWA), and EF was performed, interpreted blinded, and categorized using pre-specified cut-points where available. The primary outcome was cardiac death or resuscitated cardiac arrest. All-cause mortality and fatal or nonfatal cardiac arrest were secondary outcomes.
Mean EF significantly increased over the initial 8 weeks after MI. Testing 2 to 4 weeks after MI did not reliably identify patients at risk, whereas testing at 10 to 14 weeks did. The 20% of patients with impaired HRT, abnormal exercise TWA, and an EF <0.50 beyond 8 weeks post-MI had a 5.2 (95% confidence interval [CI] 2.4 to 11.3, p < 0.001) higher adjusted risk of the primary outcome. This combination identified 52% of those at risk, with good positive (23%; 95% CI 17% to 26%) and negative (95%; 95% CI 93% to 97%) accuracy. Similar results were observed for the secondary outcomes.
Impaired HRT, abnormal TWA, and an EF <0.50 beyond 8 weeks after MI reliably identify patients at risk of serious events. (Assessment of Noninvasive Methods to Identify Patients at Risk of Serious Arrhythmias After a Heart Attack; http://www.clinicaltrials.gov/ct/show/NCT00399503?order=1; NCT00399503).
本研究旨在确定自主神经张力与心脏电基质的联合评估能否识别出大多数心肌梗死（MI）后有发生严重事件风险的患者，并比较MI后2至4周与10至14周时的评估情况。
需要有方法来识别大多数MI后有发生严重事件风险的患者。
对MI后首周射血分数（EF）<0.50的322例患者进行了中位时间为47个月的随访。对自主神经张力进行系列评估，包括心率震荡（HRT），对心脏电基质进行评估，包括T波交替（TWA），并对EF进行评估，评估过程采用盲法，如有可用的预先设定的切点则进行分类。主要结局为心源性死亡或复苏成功的心脏骤停。全因死亡率以及致命性或非致命性心脏骤停为次要结局。
MI后的最初8周内，平均EF显著升高。MI后2至4周进行检测不能可靠地识别有风险的患者，而在10至14周进行检测则可以。MI后8周以上HRT受损、运动TWA异常且EF<0.50的患者中，主要结局的校正风险高5.2倍（95%置信区间[CI]2.4至11.3，p<0.001）。这种联合评估识别出了52%的有风险患者，具有良好的阳性（23%；95%CI 17%至26%）和阴性（95%；95%CI 93%至97%）准确性。次要结局也观察到了类似结果。
MI后8周以上HRT受损、TWA异常且EF<0.50可可靠地识别有发生严重事件风险的患者。（识别心脏病发作后有严重心律失常风险患者的非侵入性方法评估；http://www.clinicaltrials.gov/ct/show/NCT00399503?order=1；NCT00399503）
