急性心肌梗死心肌血流再灌注评价技术

TIMIFlow作为评价再灌注的方法自20世纪80年代起就一直应用于临床。TIMIFrameCount是较TIMI血流分级更为客观、更具可重复性的联系性变量指标。TMBG和TMP从心肌微血管水平对再灌注进行评价。冠脉内多普勒血流频谱变化常作为造影过程中的附加检查指标评价血管再通及心肌再灌注。同时心肌声学造影、连续心电图ST段监测、核素心肌灌注显像和心肌增强磁共振成像作为无创性的评价方法也显示出其应用价值。     

急性心肌梗死后生存时间的影响因素分析

 目的 探讨影响急性心肌梗死(acute myocardial infarction,AMI)后生存时间的因素.方法 2002-01至2004-12入选的453例AMI患者,于出院后进行随访,截止时间是2009-12.对入选时及最近一次随访病例资料进行回顾性研究.使用寿命表法分析生存率,多因素COX回归法对影响AMI患者生存时间的因素进行分析.结果 AMI患者5年生存率为93%,6年生存率为91%.影响AMI生存时间的主要因素是糖尿病史(RR=2.606,95%CI:1.233～5.509)、高血压史(RR=3.311,95%CI:1.325～8.271)、年龄(RR=1.041,95%CI:1.009～1.074)、随访NYHA等级(RR=2.043,95%CI:1.241～3.363)、再血管化(RR=2.485,95%CI:1.143～5.404)、随访LVEDD (RR=1.058,95%CI:1.003～1.115)、随访LVESV(RR=1.020,95%CI:1.008～1.031).结论 糖尿病史、高血压史、年龄、再血管化、随访NYHA等级、LVEDD、LVESV是独立危险因素.心肌梗死后积极地采取药物干预心室重塑,维持血压及血糖的正常平稳及尽早再血管化是改善心室重构,防治心力衰竭的关键因素,对心肌梗死患者远期预后和长期生存率有重要影响.     

Intravenous myocardial imaging performed serially early and late after acute myocardial infarction

The accuracy and sensitivity of myocardial imaging using intravenous Rb-81 in delineating the extent and subsequent changes in regional myocardial perfusion abnormalities were examined serially in 12 patients one to 510 days after an acute myocardial infarction. Definite regions of decreased Rb-81 uptake were noted in 10 patients with transmural infarction. There was excellent correlation between the site of perfusion abnormalities, the electrocardiographic infarct location and the region of segmental wall motion disorders. Follow-up studies revealed in 8 of 11 patients a decrease in the extent of the perfusion defect, which was associated with an improvement in the extent and/or severity of regional wall motion disorders. Conversely, wall motion abnormalities did not change in the remaining three patients in whom perfusion abnormalities persisted unchanged. We conclude that intravenous myocardial imaging permits visualization of myocardial perfusion abnormalities early after acute myocardial infarction. Serial imaging allows detection of changes in the extent of perfusion abnormalities, and, thus, might provide useful information with respect to the patient's prognosis and the effects of therapeutic interventions.Dr. O'Rourke is a Teaching Scholar of the American Heart Association. Supported in part by National Heart and Lung Institute Myocardial Infarction Research Unit Contract NOI-HV-81332 and Arteriosclerosis Grant # HL 14197     

Q-wave regression after acute myocardial infarction assessed by Tl-201 myocardial perfusion SPECT

BACKGROUND: The actual relationship between the interval change of myocardial thallium 201 (Tl-201) radioactivity in the infarct area and the pattern of Q-wave regression is still unknown. This study was conducted to evaluate their relationship after acute myocardial infarction (AMI). METHODS AND RESULTS: A total of 30 patients who had a first Q-wave AMI (11 without Q-wave regression and 19 with Q-wave regression) were retrospectively included. Two sets of 12-lead surface electrocardiograms and Tl-201 myocardial perfusion images were obtained 0 to 2 months and 14 to 84 months after the AMI event, respectively. The acute/subacute redistribution Tl-201 radioactivity was similar between the patients with and those without Q-wave regression. However, the patients with Q-wave regression had higher chronic redistribution Tl-201 radioactivity than those without Q-wave regression. Moreover, the patients with Q-wave regression presented a higher gradient in the redistribution Tl-201 radioactivity between the chronic and acute/subacute images than those without Q-wave regression. CONCLUSIONS: This study supports the role of functional recovery of stunning and/or hibernating myocardium in the disappearance of Q waves after AMI.     

用运动负荷99Tcm-MIBI SPECT心肌显像预测急性心肌梗死预后

目的：探讨运动负荷99Tcm-甲氧基异丁基异腈（MIBI）SPECT心肌断层显像判断急性心肌梗死（AMI）患者预后的价值。方法：对101例AMI患者出院前行运动负荷99Tcm-MIBI SPECT检查，随访心脏良性与不良事件的发生，分析心脏事件发生的相关因素及评估对心脏事件的预测价值。结果：多因素相关分析表明，AMI后心脏不良事件的独立预测因素是既往有心肌梗死病史，低运动积分和左室射血分数（LVEF）＜40％，。结论：AMI患者出院前行99Tcm-MIBI SPECT检查或获取运动能力，左室功能和心肌缺血状况等资料，从而鉴别高危患者，评估不良预后，有助于对高危患者及早进行介入治疗。     

Angiotensin-converting enzyme inhibitor therapy affects myocardial fatty acid metabolism after acute myocardial infarction

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitor therapy has an early mortality benefit in unselected patients with acute myocardial infarction (AMI). However, the effects of ACE inhibition on myocardial fatty acid metabolism in this patient population have not been studied. We tested the hypothesis that ACE inhibitor therapy improves myocardial fatty acid metabolism and decreases mortality rate in patients after AMI. METHODS: Forty-two patients after first anterior AMI and primary angioplasty were randomly assigned to titrated oral enalapril (n = 24) or placebo therapy (n = 18). Iodine 123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) single photon emission computed tomography imaging was performed an average of 4.8 days after AMI and 1 month after AMI. BMIPP abnormalities were quantified as a severity index by a polar map. RESULTS: There were no significant changes in baseline characteristics, cardiac function, and angiographic findings between patients in the enalapril group and patients in the placebo group. However, BMIPP severity index from acute phase to chronic phase was significantly decreased in the enalapril-treated group (118+/-48 to 82+/-36, P<.05), but not in the placebo group (123+/-65 to 115+/-58, P not significant). CONCLUSION: ACE inhibition therapy improved myocardial fatty acid metabolism and regional left ventricular function in patients after anterior AMI. BMIPP single photon emission computed tomography findings imply that this better outcome may be attributable to an improvement of cellular function with ACE inhibitors.     

Assessing prognosis after acute myocardial infarction in the thrombolytic era

The use of physiologic testing for prognostication continues to be useful and widely applied in the predischarge evaluation of patients recovering from an uncomplicated acute myocardial infarction in the thrombolytic era. Because patients with abnormal exercise test results are now routinely sent for angiography, there are no randomized trials or experimental confirmation that exercise parameters are still associated with the same prognostic value in the thrombolytic era. Nevertheless, the excellent outcomes in patients treated with thrombolytic therapy and risk stratified with exercise testing provide strong empiric support for the continued use of noninvasive testing of patients without complications after thrombolytic therapy. Reviews of patient cohorts enrolled in trials of thrombolytic therapy show that these patients have a lower incidence of multivessel disease and less evidence of ischemia (ST segment depression or thallium 201 redistribution) compared with prethrombolytic cohorts. For this and other reasons, the sensitivity and specificity of exercise variables for prognosis or detection of multivessel disease are not as strong. The addition of perfusion imaging will enhance the sensitivity for detection of ischemia within or remote from the infarct zone and will provide information regarding viability. Patients who are unable to exercise or those with poor exercise tolerance, an abnormal exercise blood pressure response, inducible ischemia, or nonsustained ventricular tachycardia are candidates for further invasive evaluation and consideration for coronary revascularization. With²⁰¹Tl imaging, evidence for increased pulmonary uptake of the tracer is indicative of high risk and a high probability of an adverse outcome with medical therapy. Low-risk patients are those who achieve their target heart rate or work load without inducible angina, ST segment depression, reversible perfusion abnormalities, or increased lung²⁰¹Tl uptake. Defect size is reflective of infarct size, and patients with extensive areas of nonreversible hypoperfusion are also at high risk for future events even in the absence of ischemia. Finally, pharmacologic stress imaging with dipyridamole, adenosine, or dobutamine has been found to be safe when employed for stress testing soon after uncomplicated infarction.     

Tl-201 reinjection enhances the detection of myocardial ischemia after acute myocardial infarction

BACKGROUND: Thallium 201 reinjection has been shown to enhance the detection of myocardial ischemia in patients with chronic coronary artery disease. However, limited data are available regarding its value in patients after acute myocardial infarction. METHODS AND RESULTS: We performed adenosine Tl-201 tomography in 126 patients in stable condition at a mean of 5 +/- 3 days after acute myocardial infarction (MI). After acquisition of redistribution images, patients were reinjected with 1 mCi of Tl-201 and reinjection images were then obtained. The stress, redistribution, and reinjection images were quantified to determine the total perfusion defect size and percent ischemia and scar. The mean age of patients was 54 +/- 10 years. Of the patients, 64% were male, 56% had Q-wave MI, 46% had anterior MI, and 34% received thrombolysis. The percent total defect size was the same on the stress-redistribution and stress-reinjection images (28.3% +/- 19.0%). The reinjection images showed an increase in ischemic defect size (14.7% +/- 13.5% vs 12.8% +/- 12.0%, P =.001) and a decrease in scar defect size (13.6% +/- 13.1% vs 15.5% +/- 13.9%, P =.001) compared with the redistribution images. The enhancement in the detection of myocardial ischemia was seen in both the infarct (P =.001) and noninfarct (P =.01) zones. CONCLUSIONS: Tl-201 reinjection enhances the detection of myocardial ischemia after acute MI compared with stress-redistribution alone.     

Intervention in acute myocardial infarction

The role of thrombolytic therapy in decreasing mortality and improving left ventricular function has been well established. The role of secondary PTCA is still being defined. Current data support a strategy of performing coronary angiography and elective PTCA only in patients with evidence of ischemia after thrombolytic therapy. Despite the trend away from routine early invasive therapy for acute myocardial infarction, accurate definition of coronary anatomy and assessment of left ventricular function will continue to be vital in the management of these patients and provide a continuing challenge for the cardiac radiographer.     

Radiography of acute myocardial infarction

In conclusion, the plain radiograph provides an insight into the hemodynamic severity of myocardial infarctions and the effected patient's ultimate prognosis. It may also be the initial indicator of one of the several complications that may accompany the evolution of an acute myocardial infarction.     

急性心肌梗死后心脏破裂临床分析

目的分析急性心肌梗死(AMI)后并发心脏破裂(CR)患者的一般资料、临床特征、早期诊断、防治方法以及预后等,以期寻找预防CR的有效手段。方法选取2011年8月至2015年12月解放军306医院心血管内科收治的AMI患者1 639例为研究对象。其中,经超声证实为CR的患者15例设为A组,其余1 624例非CR患者设为B组,比较并分析两组患者的一般资料、治疗情况等。结果 CR女性患者的发生率高于男性(P<0.05);CR患者70岁以上比例明显高于70岁以下者(P<0.05);CR患者体质量指数(BMI)<19 kg/m~2者高于BMI>19 kg/m~2者(P<0.05);合并高血压、糖尿病的患者较易发生CR。CR患者中左心室游离壁破裂者13例(86.7%),室间隔穿孔者2例(13.3%);15例患者中诊断为急性非ST段抬高型心肌梗死者1例(6.7%),急性ST段抬高型心肌梗死者14例(93.3%),其中,以前壁以及广泛前壁心肌梗死10例(66.7%)、下壁+正后壁(或同时合并右室)4例(26.7%)。结论 CR是AMI在临床中致命性的并发症,抢救成功率低;高龄、低体质量、女性、前壁心肌梗死等均是CR的易发因素;床旁心动超声图有助于早期诊断,积极的再灌注治疗是预防CR的有效手段。     

Stress radionuclide studies after acute myocardial infarction: Changes with revascularization

Background

Successful revascularization of ischemic asynergic myocardium should be followed by improvement in contractile function. However, a clear improvement is not always observed. Assessment of contractile reserve may allow a better evaluation of procedural results.

Methods and Results

To assess the changes in global and regional left ventricular ejection fraction (EF), as well as the contractile reserve after revascularization, equilibrium radionuclide angiography was performed in 16 patients with acute myocardial infarction who had periinfarct redistribution (observed in stress-rest-reinjection thallium single-photon emission computed tomography). Regional EF was defined in the asynergic region at rest, which corresponded to the infarct plus periinfarct areas. Both thallium single-photon emission computed tomography and equilibrium radionuclide angiography were performed at rest and during stress with dobutamine, up to a maximal dose of 40 μg/kg/min. The same studies were repeated 8±6 months after successful revascularization (nine coronary angioplasties and seven bypass procedures). After intervention, the thallium defect score decreased significantly at rest and during stress. Global EF changed from 45%±10% to 47%±11% (difference not significant) at rest and from 49%±12% to 63%±13% (p=0.0001) at peak stress. Regional EF changed from 27%±8% to 35%±18% (p=0.03) at rest and from 29%±10% to 56%±21% (p=0.0001) at peak stress.

Conclusions

In patients with asynergy caused by periinfarct ischemia, there can be an increase in regional but not global EF at rest after revascularization. However, both parameters improve at peak dobutamine dose. This indicates an improvement in contractile reserve.     

Assessment of myocardial viability after myocardial infarction

Conclusions  The data presented above suggest that assessment of myocardial viability after MI, particularly in those patients with severe LV dysfunction, is important for the identification of those with the highest risk, in whom revascularization can be of clinical benefit. There is growing and consistent evidence that patients with relatively large areas of dysfunctional but viable myocardium after MI have improved function, symptoms, and survival with prompt revascularization compared with medical therapy alone. Most importantly, long-term survival with revascularization in these patients is comparable with that achieved with cardiac transplantation. There are several methods available to the clinician with which to investigate the presence of tissue viability, and the evidence suggests that the scintigraphic approaches are the most sensitive. These observations suggest that noninvasive investigation of the amount of ischemic myocardium should be an important component of the diagnostic evaluation of patients with severe LV dysfunction after MI. This approach will likely enhance the often difficult process of selecting patients with poor cardiac function in whom revascularization will likely improve both the quality and quantity of life.     

Marked 99mTc-PYP myocardial accumulation immediately after reperfusion in a patient with acute myocardial infarction

We reported a case of a 72-year-old man with chest pain. An electrocardiogram showed ST segment elevation in I, II, III, aVL, aVF and V1-6 leads. 99mTc-tetrofosmin myocardial SPECT showed defect in the anterior, septal, apical and inferior walls. Coronary angiography showed 99% stenosis of the proximal right coronary artery and total occlusion of the midsegment of the left anterior descending coronary artery. Therefore, direct PTCA was performed for each lesion to achieve reperfusion. We didnt's see reperfusion injury during PTCA of the left coronary artery. On the other side, we saw severe reperfusion injury, such as slow-flow, arrhythmia and falling blood pressure during PTCA of the right coronary artery. After four hours, 99mTc-PYP myocardial SPECT showed marked uptake in the apical and inferior walls, and mild uptake in the anterior and posterior walls. After three days, severely-reduced uptake of 99mTc-PYP in the apex was noted, and mild uptake in the mid-portion of the anterior wall and the mid-portion of the inferior wall. Though reperfusion injury was seen, three was mild myocardial uptake of 99mTc-PYP in the area of the right coronary artery. On the other side, despite no reperfusion injury, there showed marked uptake during the acute phase and defect during the subacute phase in the area of the left coronary artery. Wall motion of the left ventricle was normal in the area of the right coronary artery and akinesis was seen on the left. These findings suggest that 99mTc-tetrofosmin and 99mTc-PYP myocardial SPECT are useful for visualization of reperfusion injury during the acute phase and for estimation of function during the chronic phase, better even than electrocardiogram or coronary angiography.     

Diagnosis of left ventricular free-wall rupture after acute myocardial infarction using CT

In patients with acute myocardial infarction, left ventricular free-wall rupture (LVFWR) is a well-recognized complication associated with high mortality. Accurate diagnosis of LVFWR allows successful surgical treatment and may improve survival rates. We report on two patients initially evaluated with a presumed diagnosis of thoracic aortic dissection. In both cases CT revealed the presence of LVFWR.     

CT detection of acute myocardial infarction

OBJECTIVE: The aim of this study was to evaluate the ability of contrast-enhanced CT to detect acute myocardial infarction (MI), which has not been systematically assessed. On contrast-enhanced helical chest CT, we retrospectively identified 18 patients (10 women, eight men; mean age, 66 years) with an initial MI. Each patient underwent contrast-enhanced single-detector helical chest CT within 1 month after the MI between March 2001 and June 2002. CONCLUSION: Acute MI is detectable on contrast-enhanced chest CT as an area of decreased left ventricular myocardial enhancement in a specific coronary arterial distribution.