Which Factors Determine the Development of Late Potentials After First Myocardial Infarction? A Multifactorial Analysis

A multifactorial analysis was performed to study the factors that contributed to the occurrence of late potentials on the signal-averaged electrocardiogram in 106 consecutive patients with a first myocardial infarction. Ninety-three (88%) patients received intravenous thrombolytic therapy within 6 hours of symptom onset. Thirty-two (30%) patients had a late potential on the signal-averaged electrocardiogram on day 6, including 17 of 31 (55%) in whom the infarct-related artery was occluded and 15 of 75 (20%) in whom it was patent (P = 0.0004). Twenty-three variables were analyzed by a multifactorial stepwise regression analysis. Predictors of a late potential were (1) an occluded infarct-related coronary artery (t = -3.653, P = 0.0004) and (2) the extent of myocardial necrosis as indicated by the peak serum lactate dehydrogenase level (t = 3.094, P = 0.0025). The lower incidence of late potentials when the infarct-related coronary artery was patent was independent of left ventricular election fraction and peak enzyme levels after infarction.     

急性心肌梗死静脉溶栓治疗后的早期康复护理

目的：探讨早期康复护理对急性心肌梗死静脉溶栓治疗后的效果。方法：70例急性心肌梗死静脉溶栓治疗后（无严重合并症）的患者随机分为对照组和干预组各35例,2组均在药物治疗基础上按急性心肌梗死护理操作常规护理。于预组患者同时制定每日康复护理计划,循序渐进的配合早期康复护理,包括主被动翻身,活动肢体,床上或床边的ADL等,并进行心理护理和健康教育等。结果：经过2周治疗后,与对照组比较干预组患者不适应症状及并发症发生率明显减轻或降低（P＜0．05,0．01）;平均下床时间、住院天数明显缩短（P〈0．01）。结论：对急性心肌梗死静脉溶栓治疗后患者实行系统全面的早期康复护理是安全的,有利于促进患者的康复,降低复发事件。     

急诊静脉溶栓救治急性心肌梗塞

目的:探讨在急诊室开展静脉溶栓治疗急性心肌梗塞(AMI)的疗效及安全性。方法:对76例AMI患者随机地分为尿激酶组(UK组)与对照组各38例。UK组在常规治疗的基础上选用国产UK150万U溶于0.9％的生理盐水100ml中30min静脉滴入。对照组为常规治疗。又将UK组根据开始溶栓距发病时间分为<3h、3～6h、<6h及6～12h的4个亚组。结果:冠脉再通率:总再通率UK组极显著优于对照组(57.9％与18.4％,P<0.005),UK组的亚组中,<3h者显著优于3～6h者(77.3％与37.5％,P<0.05),<6h显著优于6～12h者(66.7％与25％,P<0.05)。治疗3周时,原梗塞区R波存在例数:UK组极显著优于对照组,(42％与13％,P<0.01);异常O波导联未增加例数:UK组显著优于对照组,(47％与20％,P<0.05);心功能改善:UK组极显著优于对照组(5.3％与28.9％,P<0.01);病死率:UK组低于对照组(10.5％与15.8％,P>0.05),并低于本院开展溶栓治疗前的14％(P>0.05)。UK的副作用仅为轻度出血,无1例死于出血及严重再灌注性心律失常,溶栓及抗凝后再转入病房途中无1例危险事件发生。结论:在急诊室内开展紧急静脉溶栓治疗急性心肌梗塞有效,安全。     

Prediction of Arrhythmic Events After Acute Myocardial Infarction Using Two Methods for Late Potentials Recording

One hundred consecutive patients recovering from an acute myocardiai infarction underwent, prior to home discharge, signal-averaged electrocardiography (ECG), left ventriculography. and 24-hour Holter ECG recording. The signal-averaged ECG was recorded and analyzed using two procedures: the orthogonal bipolar XYZ lead configuration with a bidirectional filter: and a precordial unipolar lead configuration with a uonrecursive digital filter. An abnormal signal-averaged ECG was seen in 40% of patients with the XYZ system and in 30% of patients in the precordial method, abnormal ejection fraction (< 40%) in 24% of patients and high grade ectopy activity in 22%. During the 24-month follow-up period, 12 patients (12%) had an arrhythmic event defined as either sudden death (11 patients) or sustained ventricular tachycardia (1 patient). Neither the signal-averaged ECG with the XYZ configuration, the abnormal ejection fraction, nor the high grade ectopy were able to statistically predict a higher arrhythmic event rate. The signal-averaged ECG with the precordial configuration was able to statistically predict a higher arrhythmic event rate, P < 0.03; odds ratio = 3.96. The combination of the orthogonal XYZ configuration signal-averaged ECG with the ejection fraction (P < 0.01, odds ralio = 7.33), or with ejection fraction and Holter monitoring (P < 0.06. odds ratio = 6.17) was able to predict a higher arrhythmic event rate. The combination of the precordial configuration signal-averaged ECG with the ejection fraction (P < 0.002, odds ratio = 14.4), or with ejection fraction and Holter monitoring (P < 0.06. odds ratio =10) was able to better predict a higher arrhythmic event rate. The combination of a normal or abnormal signal-averaged ECG and ejection fraction gave a sensitivity, specificity, positive, or negative value prediction of arrhythmic events of 60%, 90.6%, 37.5%, and 96%, respectively. It must be emphasized that the number of arrhythmic events during the 2-year follow-up was small and further study is required to determine the true predictive value of each method for arrhythmic events.     

急性心肌梗死再灌注治疗后24小时 ST段回落程度的预后意义

目的　观察急性心肌梗死溶栓治疗后 3h、2 4h心电图ST段回落程度和出院前超声心动图心功能指标 ,探讨2 4hST段回落程度的预后意义。方法　 12 3例首次急性心肌梗死近期 (3周 )存活病例 ,测量急性期心电图ST段抬高最明显的导联在溶栓治疗开始后 3h、2 4h回落程度 (% ) ,各分为ST段回落≥ 5 0 %组和 <5 0 %组 ,比较各组在第三周超声心动图测量的心功能参数 (t检验 ) ,并以心功能参数为因变量、以急性期与再灌注有关的数据为自变量做多元逐步回归分析。结果　 3h、2 4hST段回落≥ 5 0 %组心功能参数LVEF、LVFS分别明显高于ST段回落 <5 0 %组 (P <0 .0 0 1)。逐步回归分析提示 :3h和 2 4hST段回落程度是心功能参数的独立预报因子。结论　溶栓 3h和 2 4hST段回落是重要的近期预后指标 ;2 4hST段回落有特殊的心功能预后意义 ;3～ 2 4h之间ST段继续回落可能仍有积极的意义。     

急诊静脉溶栓治疗急性心肌梗塞疗效分析

目的探讨急诊静脉溶栓治疗急性心肌梗塞的疗效.方法 68例急性心肌梗塞患者分别予以尿激酶(UK)、链激酶(SK)和重组组织型纤溶酶原激活剂(rt-PA)溶栓治疗,根据冠脉再通率和病死率分析静脉溶栓治疗急性心肌梗塞的疗效.结果溶栓治疗后冠脉再通率、心功能明显改善;无一例死于溶栓后出血.结论急诊静脉溶栓治疗急性心肌梗塞疗效好、安全、可行.     

Prognostic Implications of Loss of Late Potentials Following Acute Myocardial Infarction

The prognosis of patients following myocardial infarction is adversely affected by the finding of late potentials at the time of hospital discharge. Loss of late potentials has been previously reported during seriai testing during the first year after infarction, but it is not known whether such patients remain at risk of arrhythmic events. This study prospectively followed 243 patients after myocardial infarction. Late potentials were observed in 92 patients (group 1) at the time of hospital discharge. Of these patients, 23 no longer had late potentials at G-week follow-up and 8 had had an arrhythmic event (sudden death or ventricular tachycardia). In patients with loss of late potentials, overall QRS duration had decreased from 109 ± 11 msec at discharge to 104 ± 11 msec (P < 0.01), terminal QRS voltage rose from 15 ± 4 μV to 31 ± 9 μV (P = 0.001), and late potential duration fell from 42 ± 6 msec to 28 ± 6 msec (P = 0.001) at the 6-week study. Predictors of loss of late potentials were: initial duration of the QRS duration (P < 0.001) and terminal voltage (P < 0.005); non-Q wave infarction (P < 0.001); and being a male (P < 0.05). After the 6-week assessment, 11 additional arrhythmic events occurred during median follow-up of31 months. The risk of arrhythmic events was similar in patients with loss of late potentials and those who retained late potentials in group I (9% vs 11%, P - NS) but significantly greater than palients with no late potentials at discharge (group II, 2%). Of those patients with events beyond 6 weeks, a normal signal-averaged ECG (either lost late potentials or group II) was observed in 6/11 (55%) patients on at least one occasion prior to the occurrence of the event. Hence, a significant number of arrhythmic events occurring ≥ 6 weeks after myocardial infarction occur in palients with a normal signal-averaged ECG even when late potentials are initially present. “Loss’ of late potentials does not necessarily confer an improved prognosis in terms of risk of arrhythmic events.     

瑞替普酶院前溶栓治疗急性ST段抬高性心肌梗死临床疗效及安全性观察

目的观察瑞替普酶院前溶栓治疗急性ST段抬高性心肌梗死患者的临床疗效及安全性。方法回顾分析2010年9月-2012年12月收治的62例急性ST段抬高性心肌梗死患者,随机分为两组,其中院前组22例于120救护车上和（或）急诊科进行瑞替普酶溶栓,院内组40例于入院后进行溶栓治疗,比较两组溶栓治疗后60、120min再通率,并发各种不良反应发生率及复合终点事件发生率。结果溶栓后60、120min院前组临床判断再通率均明显高于院内组（P〈0．05）,住院4周内并发各种出血、心力衰竭、低血压及死亡发生率两组差异无统计学意义（P〉0．05）。结论瑞替普酶院前溶栓治疗急性ST段抬高性心肌梗死具有更好的临床疗效及安全性,值得基层医院临床推广。     

溶栓时间与急性心肌梗死血管再通率的临床研究

目的:探讨急性心肌梗死(AMI)后不同时间溶栓治疗对血管再通的影响。方法:回顾性分析96例AMI患者的溶栓疗效,根据发病后时间溶栓分为0～3h,>3～6h,>6～12h三组。结果:三组血管再通率分别为86.96%、74.51%、61.91%。早期治疗(0～6h)组血管再通率(78.38%)与延迟治疗(>6～12h)组的61.91%相比较,差异有显著性意义(P<0.05);两组五周病死率、反复心绞痛和反复Ⅱ度以上房室传导阻滞(AVB)相比,差异显著(P<0.01)。结论:AMI发病后6h内溶栓治疗,血管再通效果最好,住院病死率最低,但发病时间>6～12h的溶栓治疗仍可取得较好的效果。     

Determinants of the Natural Course of Ventricular Late Potentials After Thrombolytic Therapy for Acute Myocardial Infarction

The intraindividual changes of ventricular late potentials and their possible determinants were examined prospectively in 88 consecutive patients (male: 75; mean age: 58 ± 9 years) after thrombolytic therapy for acute myocardial infarction. Late potential analysis was performed 4 weeks and 12 months after acute myocardial infarction. At the same time, a left heart catheterization was performed to assess the extent of coronary heart disease and left ventricular ejection fraction. The incidence of late potential 4 weeks after acute myocardial infarction was 15% (13/88 patients). Eighteen percent (16/88) of the patients revealed changing results of late potential analysis: 9 patients lost late potential (late potential pos./neg.) 1 year after acute myocardial infarction and 7 patients presented new formation of late potential (late potential neg./pos.). Preserved late potentials were found in four patients (late potential pos./pos.). Late potential analysis remained negative in 68 patients (late potential neg./neg.). There was no influence of age, gender, site of infarction, clinical course, and medical treatment on the natural course of late potential. Changing results of late potential analysis seemed to be correlated with the evolution of left ventricular ejection fraction and the dynamics of coronary heart disease. In the group late potential pos./pos., comparable values for left ventricular ejection fraction were measured at both examinations, whereas late potential neg./neg. had a significant increase in ejection fraction. In the group late potential pos./neg., a significant improvement in left ventricular function was also measured. In contrast, the late potential neg./pos. group tended to have lower left ventricular ejection fractions 1 year after infarction. In the late potential neg./pos. and late potential pos./pos. groups, the extent of coronary artery disease returned to conditions comparable to baseline despite an initial reduction after coronary revascularization performed 4 weeks after infarction. Late potential neg./neg. and late potential pos./neg. revealed a stable benefit gained from coronary revascularization with a persistent reduction in the number of diseased vessels. Dynamic changes in the results of the signal-averaged ECG 1 year after thrombolytic therapy for acute myocardial infarction were observed in 18% of the patients. These changes seem to be correlated with the evolution of left ventricular function and the dynamics of coronary artery disease.     

Electrocardiographic Diagnosis of Acute Myocardial Infarction in the Presence of Ventricular Paced Rhythm

KOCHIADAKIS, G.E., et al. : Electrocardiographic Diagnosis of Acute Myocardial Infarction in the Presence of Ventricular Paced Rhythm. ST-segment deviation was recently described as the only ECG finding that was useful in the diagnosis of acute myocardial infarction during right ventricular pacing. This report shows that the same sign may also indicate the amount of myocardium in jeopardy and the coronary artery responsible.     

Electrophysiological Basis of Ventricular Late Potentials

EL-SHERIF, N., ET AL.: Electrophysiological Basis of Ventricular Late Potentials. The presence of late potentials on the body surface recording was correlated with ventricular activation maps of reentrant circuits in the postinfarction canine model of reentrant excitation. Late potentials were found to correlate with delayed myocardial activation. However, during a reentrant rhythm complete diastolic activity on the body surface could not be detected if the mass of electrically active cells was too small and/or if very slow conduction in part of the reentrant circuit generated low amplitude extracellular potentials. Myocardial zones responsible for late potentials during a basic rhythm (e.g., sinus rhythm) may not necessarily be part of the critical zone of slow conduction during reentrant activation. Dynamic changes in late potentials are not amenable to temporal signal averaging techniques but could be detected by a high resolution beat-to-beat recording. A thorough understanding of the electrophysiological limitations of late potentials in the signal-averaged ECG could result in better utilization of the technique in clinical practice as well as in the development of new approaches for the detection of the arrhythmogenic substrate.     

尿激酶溶栓治疗急性心肌梗死的监护

讨论了尿激酶溶栓治疗急性心肌梗死的监护重点，认为除常规监护措施外，应做好：(1）不同梗死区域发生心律失常的监护；(2)不同个体血压指标监测；(3)不同性别患的监护；(4)不同危险度患恢复期的护理干预。     

ST段抬高型心肌梗死溶栓前后心肌缺血修饰白蛋白浓度与心肌再灌注的关系

[目的]观察ST段抬高型心肌梗死（STEMI）患者溶栓前后血管再通和心肌缺血修饰白蛋白（IMA）浓度变化,探讨两者之间的关系及临床意义.[方法]入选STEMI并于发病6 h之内入院患者共80例,均予常规及尿激酶溶栓治疗,根据2 h后有无再灌注表现将患者分成无灌注组（30例）和再灌注组（50例）,两组病人于溶栓前及溶栓后2 h、4 h、6 h分别采血测IMA浓度,并于8、12、14 h采血测肌酸激酶同工酶（CK-MB）浓度.[结果]两组患者溶栓前IMA浓度无明显差异,溶栓后4～6 hIMA浓度有显著差异（P〈0.05）;再灌注组于心肌再灌注恢复后,IMA提前达峰值并回落至正常,IMA达峰值时间较肌酸激酸同工酶（CK-MB）显著提前（P〈0.05）.[结论]STEMI溶栓后心肌是否恢复再灌注与IMA浓度变化存在相关性.IMA早期明显下降可作为STEMI溶栓后心肌恢复有效再灌注的指标.     

Frequency and Significance of Left and Right Ventricular Late Potentials after Myocardial Infarction in Man

Left and right heart catheterization was conducted on 45 patients with a history of myocardial infarction in order to detect so-called ventricular late potentials by means of endocardiac mapping. The endocardiac signals were amplified 100 to 10,000 times at a low noise level using bipolar electrode catheters. The signals were stored unfiltered and visualized directly on an oscilloscope. Consistently recurring late potentials were recorded after QHS complexes in 32 patients (71%). They ranged in amplitude from 50 to 780 μV, while the coupling intervals were measured in the range of 80 to 620 ms from the beginning of the QRS complex to the beginning of the late potential. In some patients, the intracardially registered and/or Holter-monitored ventricular ectopic beats occurred with a delay, corresponding to the delayed occurrence of the ventricular late potentials.     

Thrombolysis in Acute Myocardial Infarction Following Prolonged Cardiopulmonary Resuscitation

ABSTRACT
Thrombolytic therapy was administered to a 64-year-old man with an acute anterolateral myocardial infarction who had received cardiopulmonary resuscitation (CPR) for 24 minutes. At the time of thrombolytic therapy, the patient was alert and without clinical or radiographic evidence of injury. The patient developed a retroperitoneal hematoma related to femoral line placement, as well as subcutaneous bruising of the anterior chest wall; both were self-limited. No long-term morbidity developed, and the myocardial infarction was aborted. The use of thrombolytic therapy for patients with acute myocardial infarction who have received CPR is reviewed. In the absence of clinical or radiographic evidence of trauma from CPR, patients with acute myocardial infarction should not be excluded from receiving thrombolytic therapy solely because of having had CPR or the duration of CPR.     

41例不典型急性心肌梗死临床表现及心电图分析

目的分析并评价不典型急性心肌梗死(AMI)患者的临床表现及心电图特征,为AMI的临床诊断提供参考。方法回顾分析41例不典型AMI患者的临床症状、心电图、心肌酶谱、治疗与转归。结果 41例患者以消化道及呼吸道症状为主。其中9例未见明显的ST段变化,仅见病理Q波;10例仅见ST-T缺血变化或损伤型抬高,未见病理Q波;4例延缓见梗死图形,全部为下壁AMI;3例为常规12导联无梗死图形,属于正后壁AMI;4例原梗死图形消失,V1与V2导联Q波消失,可见小r波。最终治愈率达95.12%(39/41),2例死于心力衰竭。结论应根据临床表现、心肌酶学指标变化,并结合心电图的动态改变对不典型AMI进行综合诊断,避免发生误诊。更多还原     

QT-Related Rate-Responsive Pacing During Acute Myocardial Infarction

We studied the findings in a patient who had a TX 915 pacemaker and who was suffering from an acute inferior myocardial infarction. On admission, we observed pacing at the upper rate limit due to excessive adrenergic tone. Shortly thereafter a strong vagal reaction occurred, and the pacing rate fell back to the lower rate limit. This condition was improved with atropine. Conclusions: (1) In the described condition the TX pacemaker behaved in a very "physiological" fashion; (2) Sudden strong cholinergic activity lengthened the QT interval; (3) Programming of a steep slope must be avoided in coronary artery disease; (4) Stimulus-T-wave intervals at maximal adrenergic and cholinergic stimulation should be taken into account when programming the slope and the T-wave sensing window.     

静脉溶栓序贯给药法对急性心肌梗塞冠脉再通疗效的观察

目的观察静脉溶栓序贯给药法对急性心肌梗塞早期冠脉再通的疗效。方法２０５例ＡＭＩ患者随机分成序贯组（溶栓前肝素－尿激酶－溶栓后肝素）１０７例，和对照组（９８例）。尿激酶溶栓前序贯组先用肝素５０００Ｕ，而对照组只用安慰剂（尿激酶－肝素）。结果序贯组的早期冠脉再通率明显高于对照组，分别为７１．０３％和５２．０４％，Ｐ＜０．０１，前者的ＳＴ段回落和Ｔ波反转也明显快于后者。两组出血并发症相似。结论静脉溶栓序贯给药法明显提高早期冠脉再通率而不增加出血危险性。