Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
Circulation. 2010 Nov 30;122(22):2281-7. doi: 10.1161/CIRCULATIONAHA.109.935338. Epub 2010 Nov 15.
The frequency of papillary muscle infarction (PapMI) without rupture has not been fully investigated in vivo. Furthermore, the relationship between papillary muscle dysfunction and mitral regurgitation (MR) has been controversial in patients with ST-segment elevation myocardial infarction. Therefore, the aim of this study was to assess the frequency and clinical characteristics of PapMI without rupture using late gadolinium-enhanced magnetic resonance imaging (MRI) in patients with ST-segment elevation myocardial infarction.
One hundred eighteen ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention underwent cardiac MRI twice 9±4 days and 8±1 months (n=104) after myocardial infarction. MR was categorized by echocardiography. Of these patients, 40% were found to have late gadolinium enhancement of papillary muscle, in which the posterior papillary muscle was involved more frequently than the anterior papillary muscle (77% versus 26%; P<0.001). PapMI was encountered more frequently in patients with left circumflex and right coronary artery lesions compared with left anterior descending artery lesion (78%, 48%, and 13%; P<0.001). By multiple logistic regression analysis, only coaptation height was identified as an independent predictor of the presence of MR. The second cardiac magnetic resonance imaging showed that the infarct size had a positive correlation with left ventricular end-diastolic volume (r=0.41, P<0.001) and that PapMI was not associated with left ventricular remodeling (P=0.31). Deterioration of MR was not observed in patients with PapMI.
PapMI is more frequent than previously thought yet appears to have significant clinical latency. The size of the myocardial infarction, but not the presence of PapMI, seems to affect left ventricular remodeling, and PapMI is not obligatorily associated with MR.
在体内尚未充分研究无破裂的乳头肌梗死（PapMI）的频率。此外，在 ST 段抬高型心肌梗死患者中，乳头肌功能障碍与二尖瓣反流（MR）之间的关系一直存在争议。因此，本研究旨在使用 ST 段抬高型心肌梗死患者的心脏磁共振延迟钆增强成像（MRI）评估无破裂的乳头肌梗死的频率和临床特征。
118 例接受直接经皮冠状动脉介入治疗的 ST 段抬高型心肌梗死患者在心肌梗死后 9±4 天和 8±1 个月（n=104）时进行了两次心脏 MRI。MR 通过超声心动图进行分类。其中 40%的患者发现有乳头肌延迟钆增强，其中后乳头肌比前乳头肌更常受累（77%比 26%；P<0.001）。与左前降支病变相比，左回旋支和右冠状动脉病变的患者更常发生 PapMI（78%、48%和 13%；P<0.001）。通过多变量逻辑回归分析，仅瓣叶对合高度被确定为 MR 存在的独立预测因子。第二次心脏磁共振成像显示梗死面积与左心室舒张末期容积呈正相关（r=0.41，P<0.001），而 PapMI 与左心室重构无关（P=0.31）。在有 PapMI 的患者中，MR 恶化并未观察到。
PapMI 的发生率高于先前的预期，但似乎具有明显的临床潜伏期。心肌梗死的大小，而不是 PapMI 的存在，似乎影响左心室重构，并且 PapMI 不一定与 MR 相关。
