Ruptured papillary muscle after acute myocardial infarction

Two cases of rupture of the left posterior papillary muscle after acute myocardial infarction are reported. The diagnostic features of this uncommon complication of myocardial infarction are discussed.     

QTc intervals in acute myocardial infarction: First-year prognostic implications

Corrected QT (QT_c) intervals were measured retrospectively in 160 consecutive survivors of acute myocardial infarction under 66 years of age. Calculations were made the first 2 d in the coronary care unit (CCU), the first post-CCU day, at discharge, and at 1–3, 6, and 12 months after discharge. All patients were in sinus rhythm and without bundle branch block at discharge from the hospital. Sixteen patients died during the first follow-up year. Twenty patients suffered a reinfarction, five of whom died. The highest QT_c values were registered in the CCU and the lowest at the 1-year control. Patients with subendocardial infarcts had longer QT_c intervals than those with transmural infarcts, especially during the acute phase. Patients with inferior infarcts had shorter QT_c intervals during the CCU period. Those who reinfarcted or died a cardiac death (particularly when sudden) during the follow-up year had longer QT_c intervals during the post-CCU phase. A multivariate analysis of risk factors revealed that the QT_c interval at discharge was of significant independent value for predicting major cardiac events after discharge from the hospital. It is concluded that repeated measurements of QT_c may be of value when assessing prognosis after acute myocardial infarction.     

The aetiology and prognostic implications of reciprocal electrocardiographic changes in acute myocardial infarction

The relations between reciprocal ST segment depression in the electrocardiogram and infarct size and 10 year prognosis were studied in 315 patients who survived for at least 28 days after a first anterior or inferior myocardial infarction. ST depression was more common in inferior infarcts (72%) than in anterior (37%) ones. It occurred more frequently in complicated infarcts and in the presence of considerable ST elevation. Patients experiencing second or third degree heart block were significantly more likely to show reciprocal changes. The rise in peak cardiac enzyme concentration was higher in patients showing ST depression. In patients with ST depression, peak creatine kinase concentration was 46% higher, aspartate aminotransferase was 39% higher, and lactate dehydrogenase 29% higher after correction for site and complications. A discriminant function analysis selected infarct site, peak aspartate aminotransferase, and magnitude of ST elevation as predictors of the occurrence of ST depression. Age, severity, and smoking status did not significantly improve discrimination. Despite larger increases in peak enzyme concentrations patients with ST depression had marginally fewer subsequent episodes of unstable angina or fatal or non-fatal infarction and a marginally lower 10 year death rate. Neither difference was statistically significant. ST depression occurring early in the acute phase of myocardial infarction is likely to be a reflection of electrophysiological changes taking place at the site of the infarct that is manifested in the contralateral surface of the heart. Other causes, however, such as transient ischaemia at the site of the reciprocal changes or extension of the infarct to contiguous areas cannot be excluded in all cases.     

Cardiogenic shock due to papillary muscle rupture in acute myocardial infarction

We report a case of papillary muscle rupture complicating acute myocardial infarction which resulted in acute cardiogenic shock. The patient underwent urgent replacement of the mitral valve and made an uncomplicated recovery.     

The aetiology and prognostic implications of reciprocal electrocardiographic changes in acute myocardial infarction.

The relations between reciprocal ST segment depression in the electrocardiogram and infarct size and 10 year prognosis were studied in 315 patients who survived for at least 28 days after a first anterior or inferior myocardial infarction. ST depression was more common in inferior infarcts (72%) than in anterior (37%) ones. It occurred more frequently in complicated infarcts and in the presence of considerable ST elevation. Patients experiencing second or third degree heart block were significantly more likely to show reciprocal changes. The rise in peak cardiac enzyme concentration was higher in patients showing ST depression. In patients with ST depression, peak creatine kinase concentration was 46% higher, aspartate aminotransferase was 39% higher, and lactate dehydrogenase 29% higher after correction for site and complications. A discriminant function analysis selected infarct site, peak aspartate aminotransferase, and magnitude of ST elevation as predictors of the occurrence of ST depression. Age, severity, and smoking status did not significantly improve discrimination. Despite larger increases in peak enzyme concentrations patients with ST depression had marginally fewer subsequent episodes of unstable angina or fatal or non-fatal infarction and a marginally lower 10 year death rate. Neither difference was statistically significant. ST depression occurring early in the acute phase of myocardial infarction is likely to be a reflection of electrophysiological changes taking place at the site of the infarct that is manifested in the contralateral surface of the heart. Other causes, however, such as transient ischaemia at the site of the reciprocal changes or extension of the infarct to contiguous areas cannot be excluded in all cases.     

Ultrasonic diagnosis of papillary muscle dysfunction in patients with acute myocardial infarct

A study of 123 patients with acute myocardial infarction demonstrated the potentials of combined use of sectoral scanning and Doppler echocardiography in the diagnosis of the papillary muscle dysfunction syndrome. Two basic pathogenetic mechanisms of papillary muscle dysfunction associated with acute myocardial infarction are identified: direct involvement of the papillary muscles and papillary muscle dysfunction developing in cases of marked left-ventricular dilatation associated with acute aneurysm of the heart. Two-dimensional impulse Doppler echocardiography is found to be a more sensitive method, as compared to sectoral scanning, in the diagnosis of mitral lesions in patients with acute myocardial infarction.     

The clinical implications of electrocardiographic changes in first acute myocardial infarction

To assess the prognostic significance and the clinical implications of the electrocardiographic findings of the first acute myocardial infarction, the in-hospital mortality and complications and three-year follow-up of 180 patients were analyzed. The patients were divided according to the infarction type (transmural, non-transmural), the site, (anterior, inferior including posterior) and the absence or presence of ST depression in leads facing the site of infarction. The peak enzyme concentrations were significantly higher in those with transmural infarcts than in those with non-transmural infarcts, in anterior infarcts compared to inferior infarcts, and in those sites with ST depression than those without. The early complications of cardiogenic shock, congestive cardiac failure, and complete heart block were significantly higher in transmural infarcts compared to non-transmural, while late complications and mortality were the same in all groups and subgroups. This study demonstrated that ECG changes in the first acute myocardial infarction are of prognostic significance for the early clinical course, but cannot predict the late course or subsequent coronary events.     

Mitral valve surgery for acute papillary muscle rupture following myocardial infarction

BACKGROUND AND AIM OF THE STUDY: Acute papillary muscle rupture (PMR) is a rare but fatal complication of myocardial infarction (MI). Surgery represents the best treatment option, but carries a high risk. Our experience of emergency mitral valve surgery in patients with acute PMR following MI during the past 22 years is reviewed. METHODS: Between 1978 and 2000, 33 patients (20 males, 13 females; mean age 64 years; range: 46-80) underwent emergency surgery for acute post-infarct PMR in our institution. The site of MI was anterior in three patients and inferior in 30. Preoperatively, 17 patients had an intra-aortic balloon pump (IABP) inserted, 26 were on inotropic support, and 17 were ventilated. Twenty patients (61%) underwent concomitant coronary bypass grafting (CABG). The valve was replaced in 31 patients and repaired in two. Mean (+/- SD) duration of follow up was 63+/-54 months (range: 0-183 months). RESULTS: Early mortality (in-hospital) was 21% (n = 7). Factors associated with significant risk of early mortality included raised preoperative serum creatinine (p = 0.02), need for preoperative inotropic support (p = 0.03) and preoperative ventilation (p = 0.03). Raised preoperative serum creatinine remained significant on multiple logistic regression (p = 0.04). Postoperatively, 21 patients required an IABP. Mean duration of intensive care unit stay was 4+/-2.5 days (range: 0-10 days). Survival, including in-hospital mortality, at one, five and 10 years was 75+/-7.4, 65+/-8.6 and 32+/-9.7%, respectively. Four patients required valve-related reoperation (three for a paraprosthetic leak, one for failed repair). CONCLUSION: Patients with acute post-infarct PMR present in a severely compromised state. Early mortality is high, but the intermediate outcome is encouraging for operative survivors.     

Plasma zinc in acute myocardial infarction. Diagnostic and prognostic implications.

Zinc is a metal component of many important enzymes, and its availability controls the rate of synthesis of nucleic acids and protein. Serum zinc levels have been shown to fall after acute tissue injury, including myocardial infarction. The purpose of this clinical study was to examine the value of plasma zinc measurements in a coronary care unit. Studies were made in 188 patients: 88 with unequivocal myocardial infarction, 52 controls, and 48 in a borderline group. Patients with myocardial infarction showed a fall in plasma zinc within the first three days, whereas patients in the other two groups did not. The difference in the mean minimum zinc levels between the groups with and without infarction was highly significant. In patients with myocardial infarction there was good correlation between the minimum plasma zinc level and the peal value of plasma enzymes, and also with some clinical estimators of prognosis. A fall in plasma zinc is a reliable diagnostic test for acute myocardial infarction, and the extent of the fall has prognostic implications.     

The new definition of myocardial infarction: diagnostic and prognostic implications in patients with acute coronary syndromes

BACKGROUND: The clinical implications of the recently revised criteria for diagnosis of acute myocardial infarction (AMI) in patients with suspected acute coronary syndromes are unknown. METHODS: To evaluate the prognostic implications of the new diagnostic criteria for AMI, we studied 493 consecutive patients with suspected acute coronary syndromes admitted to University of Michigan, Ann Arbor, between May 1, 1999, and January 1, 2000. Patients with positive cardiac enzymes and symptoms suggestive of coronary ischemia (n = 275) were divided into 2 groups: group A, with elevated peak creatine kinase-MB fraction and/or new electrocardiographic changes suggestive of AMI regardless of troponin status (diagnosed as AMI by old criteria), and group B, with normal peak creatine kinase-MB fraction but elevated troponin I level (additional patients diagnosed as having AMI by new criteria). RESULTS: As compared with group A (n = 224), patients in group B (n = 51) were older women, with increased comorbidities such as previous stroke or aortic stenosis, and had fewer in-hospital procedures. In-hospital adverse events (reinfarction, heart failure, shock, and mortality) were similar between the groups, whereas 6-month mortality was higher among group B patients (16.3% vs 5.8%; P =.03). This difference was not statistically significant after adjustment for differences in baseline characteristics between the groups (odds ratio, 1.6; 95% confidence interval, 0.5-5.9). CONCLUSIONS: The new criteria result in a substantial increase in the diagnosis of AMI. Furthermore, they help to identify patients with acute coronary syndromes who have greater comorbidities and worse 6-month outcomes who are otherwise missed by the old criteria. Additional studies are needed to confirm these preliminary findings and to determine the financial implications of the new criteria.     

急性心肌梗死患者入院临床特征与近期预后的相关性

目的：分析急性心肌梗死（AMI）患者的入院临床特征与近期预后结局的相关性。方法：回顾性分析因初发 AMI住院治疗患者108例的临床资料,依据是否发生主要不良心脏事件（MACE）分为：事件组（61例）和非事件组（47例）,随访1年。收集、分析并比较两组患者的临床特征,以及 AMI临床特征与 MACE发生率的相关性。结果：与非事件组相比,事件组患者的平均年龄较大,平均动脉压（MAP）较高,左室射血分数（LVEF）降低,左室舒张末期内径（LVEDd）、Killip2级以上比例、Grace评分、多支病变增加,差异均有统计学意义（P＜0.05～＜0.01）。单因素相关分析显示年龄、MAP、LVEF、Killip2级以上比例、Grace评分、多支病变率与 MACE发生率存在相关性（P＜0.05～＜0.01）;经多因素 Logistic回归分析显示,年龄（OR＝0.827）、LVEF（OR＝0.624）、Grace评分（OR＝0.589）、多支病变率（OR＝0.461）是 AMI患者发生 MACE的危险因素（P均＜0.05）。结论：高龄、低左室射血分数、Grace评分高以及多支病变是急性心肌梗死患者近期发生主要不良心脏事件的高危因素。     

合并代谢综合征的急性心肌梗死患者临床特征

目的 探讨合并代谢综合征(MS)的急性心肌梗死(AMI)患者的临床特征.方法 对81例合并MS的AMI患者及94例无MS的AMI患者进行回顾性研究,比较两组患者的基础临床情况、诱发因素、临床表现、梗死部位及心肌酶.结果与非 MS组相比,MS组年龄较大,女性患者所占比率较高(34.6%比17.0%,P＜0.01),吸烟和冠心病家族史比率较低(分别为43.2%比59.6%,13.6%比25.5%,均P＜0.05),饱餐后或情绪激动时发病率较高(分别为18.5%比7.4%,13.6%比4.3%,均P＜0.05),有胸痛者少(66.7%比81.9%,P＜0.05),心功能≥KillipⅡ级者较多(35.8%比22.3%,P＜0.05),住院病死率高(22.2%比10.6%.P＜0.05),前壁范围所占比率较高(51.9%比36.2%,P＜0.05),肌酸激酶同工酶较高[(147±19)U/L比(122±14)U/L,P＜0.01].结论 与无MS的AMI患者相比,合并MS的AMI患者年龄较大,女性患者较多,近期预后较差.     

Congestive heart failure with preserved left ventricular systolic function after acute myocardial infarction: clinical and prognostic implications

AIMS: To characterise the prevalence, in-hospital complications, management, and long-term outcome of patients with congestive heart failure but preserved left ventricular systolic function after acute myocardial infarction. METHODS: 3166 consecutive patients screened for entry in the Bucindolol Evaluation in Acute Myocardial Infarction Trial with definite acute myocardial infarction and echocardiographic assessment of left ventricular systolic function were included between 1998 and 1999 in this prospective observational study. Main outcome measures were occurrences of in-hospital complications and all cause mortality. RESULTS: Congestive heart failure was seen during hospitalisation in 1464 patients (46%), 717 patients had preserved left ventricular systolic function (wall motion index > or =1.3 corresponding to ejection fraction > or =0.40), and 732 patients had systolic dysfunction (wall motion index <1.3). One year mortality in patients with no heart failure, heart failure with preserved systolic function, and heart failure with systolic dysfunction were 6, 22 and 35%, P<0.0001. Unadjusted risk of death from all causes associated with heart failure and preserved systolic function was 3.3 (95% CI 2.8-4.0), and after adjustment for baseline characteristics and left ventricular systolic function in multivariate Cox proportional hazards analysis the risk was 2.1 (95% CI 1.7-2.6), P<0.0001. CONCLUSIONS: Congestive heart failure is frequently present in patients with preserved left ventricular systolic function, and is associated with increased risk of in-hospital complications and death following acute myocardial infarction.     

内皮细胞的损伤与急性心肌梗塞

本研究以循环内皮细胞（ＣＥＣ）作为血管内皮损伤的指示物，以血浆内皮素（ＥＴ－１）反映血管内皮的功能变化，研究了急性心肌梗塞（ＡＭＩ）患者内皮细胞的损伤和功能变化。４１例ＡＭＩ患者分为两组，Ａ组２６例，无梗塞后缺血事件及心力衰竭；Ｂ组１５例，有上述并发症。２１例健康人做为对照。动态测定患者在入院后７２小时的血浆ＥＴ－１水平和ＣＥＣ计数。结果显示：两组患者血浆ＥＴ－１和ＣＥＣ均在ＡＭＩ发病的早期４小时即达峰值，以后随时间推移而下降，但在７２小时内各测定值均高于正常对照组（Ｐ＜０．０１）。两组不同的是：具有合并症的ＡＭＩ患者（Ｂ组），其血浆ＥＴ－１水平和ＣＥＣ计数在各个时间点均高于Ａ组患者（Ｐ＜０．０１）；且随时间下降速度缓慢，在４８小时和７２小时仍呈较高水平，均高于Ａ组患者（Ｐ＜０．０１）；两组患者的ＥＴ－１和ＣＥＣ均呈显著的正相关（Ｐ＜０．００１）。结论：血浆ＥＴ－１水平和ＣＥＣ数量在ＡＭＩ早期显著增加，二者可做为心肌梗塞内皮细胞损伤和功能变化的指示物；在有并发症的ＡＭＩ中二者呈现持续升高，这可能与梗塞后缺血的发生和心脏功能减低有关。     

Acute myocardial infarction with papillary muscle rupture

The subject of this report is a 57-year-old obese, hypertensive woman who had been well until the onset of severe chest pain and hypotension. She had to be defibrillated four times on her way to the hospital. The diagnosis of acute inferior-posterior infarction was made by electrocardiogram (ECG) and there was a markedly elevated serum creatine kinase (CK) (including the MB fraction). The patient had a very low cardiac output and ejection fraction. A lung scan revealed possible pulmonary embolism for which she was anticoagulated. She remained hypotensive and hypoxemic and, on Day 17 of her hospital stay, she had a bout of severe dyspnea. A new systolic murmur was heard and the clinical diagnosis of ruptured papillary muscle was made and confirmed by echocardiography, and later at autopsy. All three coronary arteries were severely atherosclerotic and, in addition, the right coronary artery was completely closed by a thrombus. This case clearly illustrates the major pathological changes in the heart that correlate with the clinical findings in patients with a myocardial infarct that is complicated by left ventricular papillary muscle rupture. The pathophysiological effects of this condition, as illustrated in this case report, include the following: 1. The posterior papillary muscle was almost completely separated from its base, with only a thin strip of muscle intact. The mitral valve thus was insufficient (a “flail valve“); this markedly reduced the ejection fraction of the left ventricle, increased its end-diastolic volume and pressure, produced a damming of blood in the pulmonary circulation, and this resulted in the pulmonary edema seen on the chest x-ray. 2. Cardiac hypertrophy (weight = 561 g) was undoubtedly the result of the increased workload imposed on the left ventricle by the systemic arterial hypertension that this patient had for several years. A high blood pressure that persists after a myocardial infarct predisposes to myocardial rupture, but was probably not a risk factor in her case since it did not persist. 3. The cause of the myocardial infarct was the thrombotic occlusion of the right coronary artery (on top of severe three-vessel coronary atherosclerosis), which resulted in infarction of the right as well as the posterior left ventricle and can partly explain the mistaken clinical impression that she had pulmonary emboli.