The Heart Centre, Department of Cardiology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark.
JACC Cardiovasc Imaging. 2013 Aug;6(8):851-60. doi: 10.1016/j.jcmg.2013.05.009. Epub 2013 Jul 10.
This study sought to hypothesize that global longitudinal strain (GLS) as a measure of infarct size, and mechanical dispersion (MD) as a measure of myocardial deformation heterogeneity, would be of incremental importance for the prediction of sudden cardiac death (SCD) or malignant ventricular arrhythmias (VA) after acute myocardial infarction (MI).
SCD after acute MI is a rare but potentially preventable late complication predominantly caused by malignant VA. Novel echocardiographic parameters such as GLS and MD have previously been shown to identify patients with chronic ischemic heart failure at increased risk for arrhythmic events. Risk prediction during admission for acute MI is important because a majority of SCD events occur in the early period after hospital discharge.
We prospectively included patients with acute MI and performed echocardiography, with measurements of GLS and MD defined as the standard deviation of time to peak negative strain in all myocardial segments. The primary composite endpoint (SCD, admission with VA, or appropriate therapy from a primary prophylactic implantable cardioverter-defibrillator [ICD]) was analyzed with Cox models.
A total of 988 patients (mean age: 62.6 ± 12.1 years; 72% male) were included, of whom 34 (3.4%) experienced the primary composite outcome (median follow-up: 29.7 months). GLS (hazard ratio [HR]: 1.38; 95% confidence interval [CI]: 1.25 to 1.53; p < 0.0001) and MD (HR/10 ms: 1.38; 95% CI: 1.24 to 1.55; p < 0.0001) were significantly related to the primary endpoint.
GLS (HR: 1.24; 95% CI: 1.10 to 1.40; p = 0.0004) and MD (HR/10 ms: 1.15; 95% CI: 1.01 to 1.31; p = 0.0320) remained independently prognostic after multivariate adjustment. Integrated diagnostic improvement (IDI) and net reclassification index (NRI) were significant for the addition of GLS (IDI: 4.4% [p < 0.05]; NRI: 29.6% [p < 0.05]), whereas MD did not improve risk reclassification when GLS was known.
Both GLS and MD were significantly and independently related to SCD/VA in these patients with acute MI and, in particular, GLS improved risk stratification above and beyond existing risk factors.
本研究旨在假设，作为梗死面积测量指标的整体纵向应变（GLS）和作为心肌变形异质性测量指标的机械离散度（MD），对于预测急性心肌梗死（MI）后心脏性猝死（SCD）或恶性室性心律失常（VA）具有重要的增量意义。
急性 MI 后 SCD 是一种罕见但潜在可预防的晚期并发症，主要由恶性 VA 引起。先前已有研究表明，新型超声心动图参数如 GLS 和 MD 可识别出患有慢性缺血性心力衰竭的患者，这些患者发生心律失常事件的风险增加。急性 MI 入院期间的风险预测很重要，因为大多数 SCD 事件发生在出院后的早期。
我们前瞻性纳入了急性 MI 患者，并进行了超声心动图检查，GLS 和 MD 的测量定义为所有心肌节段达最大负向应变时间的标准差。采用 Cox 模型分析主要复合终点（SCD、因 VA 入院或原发性预防性植入式心脏复律除颤器[ICD]的适当治疗）。
共纳入 988 例患者（平均年龄：62.6±12.1 岁；72%为男性），其中 34 例（3.4%）发生了主要复合结局（中位随访：29.7 个月）。GLS（风险比[HR]：1.38；95%置信区间[CI]：1.25 至 1.53；p<0.0001）和 MD（HR/10 ms：1.38；95% CI：1.24 至 1.55；p<0.0001）与主要终点显著相关。
GLS（HR：1.24；95% CI：1.10 至 1.40；p=0.0004）和 MD（HR/10 ms：1.15；95% CI：1.01 至 1.31；p=0.0320）在多变量调整后仍具有独立的预后意义。GLS 的加入显著提高了综合诊断改善（IDI）和净重新分类指数（NRI）（IDI：4.4%[p<0.05]；NRI：29.6%[p<0.05]），而 MD 并不能改善已知 GLS 时的风险再分类。
GLS 和 MD 均与这些急性 MI 患者的 SCD/VA 显著且独立相关，尤其是 GLS 可在现有危险因素的基础上进一步改善风险分层。
