Ventricular premature beats and mortality after myocardial infarction.

To assess the role of ventricular premature beats in influencing mortality of coronary patients, 1739 men with prior myocardial infarction were monitored for ectopic activity for one hour at a standard base-line examination, and followed for mortality for periods up to four years (average, 24.4 months). Analyses of survival taking into account other important prognostic variables establish that the presence of complex premature beats (R on T, runs of 2 or more, multiform or bigeminal premature beats) in the monitoring hour is associated with a risk of sudden coronary death three times that of the men free of complex ventricular premature beats. The corresponding risk of death from any cause is twice that of men without such complex beats in the hour. These arrhythmias make an independent contribution to increased risk of death that persists over the length of this observation period.     

Analyses of creatine kinase isoforms to detect early diagnosis of reinfarction and reperfusion after acute myocardial infarction

The detection of reinfarction and reperfusion of the acute myocardial infarction (AMI) in the early phase was studied by monitoring the 34 AMI patients of their changes in creatine kinase (CK, EC 2.7.3.2) isoforms level. CK isoform was assayed by immunoinhibition method using monoclonal antibody. The increased ratio of serum CK-MM3/CK-MM1 after the onset was observed earlier than conventional serum parameters such as CK-MB, CK-MM3, PK and LD and it was almost the same as myoglobin in both reperfused and non-reperfused patients. The increased ratio of CK-MM3/CK-MM1 in reperfusion group was gradually reduced after 5 hours of onset earlier and lowered to reference level two to three times more rapidly than in non-reperfusion group. The ratio of serum CK-MM3/CK-MM1 with AMI increased much more sharply compared to that of after hard exercise. Therefore, monitoring the ratio of patients serum CK-MM3/CK-MM1 with AMI (at serial times, or periodically, or every 3 hours, etc.) is significant for clinical diagnosis.     

摘除性腺对大鼠实验性心肌梗塞后死亡率和左室功能的影响

本文观察了去性腺对大鼠心肌梗塞后的死亡率及左室功能的影响。雌雄鼠于去性腺后三周分别作左冠状动脉结扎术或假手术,发现术后9日内的死亡率雄性去性腺梗塞组(GMI)显著低于对照梗塞组(CMI),而雌性两组间无显著差别。术后9天测得的dp/dtmax,-dp/dtmax及LVSP,雄性去性腺假手术组(GS)均较未去性腺假手术组(CS)低;雄性GMI组的这三项指标与CMI组相比虽无明显差别但已达到与GS组相同水平。梗塞组均见心肌纤维直径增大,但雄性以GMI组更明显而雌性则CMI组更明显。实验结果提示心肌梗塞后左室功能的代偿和恢复有性腺活动的参与。     

Digoxin therapy and mortality after myocardial infarction. Experience in the MILIS Study

Recent studies have led to controversy about whether long-term digoxin therapy after confirmed or suspected myocardial infarction increases mortality. We analyzed the mortality experience in 903 patients enrolled in the Multicenter Investigation of Limitation of Infarct Size (MILIS). As in previous studies, the decision to treat or not to treat with digoxin was made by the patient's personal physician on the basis of the usual clinical indications. Cumulative mortality was 28 percent for the 281 digoxin-treated patients as compared with 11 percent for the 622 patients who did not receive digoxin (P less than 0.001; follow-up interval, six days to 36 months; mean, 25.1 months). However, patients treated with digoxin had more base-line characteristics predictive of mortality than did their counterparts. Adjustment for these differences with two separate applications of the Cox method yielded P values of 0.14 and 0.34 for tests of difference in mortality, providing no evidence for a significant excess mortality associated with digoxin. Thus, the findings in the MILIS population do not support the assertion that digoxin therapy is excessively hazardous after infarction, but the existence of an undetected harmful effect can only be excluded with a randomized study. Until the results of such a study are available, we recommend careful consideration of whether any treatment of ventricular dysfunction is actually needed, consideration of alternatives to digoxin therapy, and restriction of digoxin use to the subgroup of patients (with severe chronic congestive failure and a dilated left ventricle) previously shown to have a beneficial clinical response.     

Short-term diabetes attenuates left ventricular dysfunction and mortality rates after myocardial infarction in rodents

OBJECTIVES:

To investigate the effects of hyperglycemia on left ventricular dysfunction, morphometry, myocardial infarction area, hemodynamic parameters, oxidative stress profile, and mortality rate in rats that had undergone seven days of myocardial infarction.

INTRODUCTION:

Previous research has demonstrated that hyperglycemia may protect the heart against ischemic injury.

METHODS:

Male Wistar rats were divided into four groups: control-sham, diabetes-sham, myocardial infarction, and diabetes + myocardial infarction. Myocardial infarction was induced 14 days after diabetes induction. Ventricular function and morphometry, as well as oxidative stress and hemodynamic parameters, were evaluated after seven days of myocardial infarction.

RESULTS:

The myocardial infarction area, which was similar in the infarcted groups at the initial evaluation, was reduced in the diabetes + myocardial infarction animals (23±3%) when compared with the myocardial infarction (42±7%, p<0.001) animals at the final evaluation. The ejection fraction (22%, p = 0.003), velocity of circumferential fiber shortening (30%, p = 0.001), and left ventricular isovolumetric relaxation time (26%, p = 0.002) were increased in the diabetes + myocardial infarction group compared with the myocardial infarction group. The diabetes-sham and diabetes + myocardial infarction groups displayed increased catalase concentrations compared to the control-sham and myocardial infarction groups (diabetes-sham: 32±3; diabetes + myocardial infarction: 35±0.7; control-sham: 12±2; myocardial infarction: 16±0.1 pmol min^-1 mg^-1 protein). The levels of thiobarbituric acid-reactive substances were reduced in the diabetes-sham rats compared to the control-sham rats. These positive adaptations were reflected in a reduced mortality rate in the diabetes + myocardial infarction animals (18.5%) compared with the myocardial infarction animals (40.7%, p = 0.001).

CONCLUSIONS:

These data suggest that short-term hyperglycemia initiates compensatory mechanisms, as demonstrated by increased catalase levels, which culminate in improvements in the ventricular response, infarcted area, and mortality rate in diabetic rats exposed to ischemic injury.     

Effects of socioeconomic status on access to invasive cardiac procedures and on mortality after acute myocardial infarction.

BACKGROUND: Universal health care systems seek to ensure access to care on the basis of need rather than income and to improve the health status of all citizens. We examined the performance of the Canadian health system with respect to these goals in the province of Ontario by assessing the effects of neighborhood income on access to invasive cardiac procedures and on mortality one year after acute myocardial infarction. METHODS: We linked claims for payment for physicians' services, hospital-discharge abstracts, and vital-status data for all patients with acute myocardial infarction who were admitted to hospitals in Ontario between April 1994 and March 1997. Patients' income levels were imputed from the median incomes of their residential neighborhoods as determined in Canada's 1996 census. We determined rates of use and waiting times for coronary angiography and revascularization procedures after the index admission for acute myocardial infarction and determined death rates at one year. In multivariate analyses, we controlled for the patient's age, sex, and severity of disease; the specialty of the attending physician; the volume of cases, teaching status, and on-site facilities for cardiac procedures at the admitting hospital; and the geographic proximity of the admitting hospital to tertiary care centers. RESULTS: The study cohort consisted of 51,591 patients. With respect to coronary angiography, increases in neighborhood income from the lowest to the highest quintile were associated with a 23 percent increase in rates of use and a 45 percent decrease in waiting times. There was a strong inverse relation between income and mortality at one year (P<0.001). Each $10,000 increase in the neighborhood median income was associated with a 10 percent reduction in the risk of death within one year (adjusted hazard ratio, 0.90; 95 percent confidence interval, 0.86 to 0.94). CONCLUSIONS: In the province of Ontario, despite Canada's universal health care system, socioeconomic status had pronounced effects on access to specialized cardiac services as well as on mortality one year after acute myocardial infarction.     

Higher mortality in women after ST-segment elevation myocardial infarction in very young patients

Introduction

Data on mortality in young patients with ST-segment elevation myocardial infarction (STEMI) when compared to older people or regarding therapeutic strategies are contradictory. We investigate the prognosis of women under 40 after STEMI in a prospective nationwide acute coronary syndrome registry.

Material and methods

We analyzed all 527 consecutive men and women (12.3% females) aged from 20 to 40 years (mean 35.7 ±4.5) presenting with STEMI, of all 26035 STEMI patients enrolled.

Results

Differences between genders in the major cardiovascular risk factors, clinical presentation, extent of the disease and time to reperfusion were insignificant. The majority of patients (67%) underwent coronary angiography followed by primary percutaneous coronary intervention (PCI) in 79.9% of them. A 92% reperfusion success rate measured by post-procedural TIMI 3 flow was achieved. There were no significant differences between genders in the administration of modern pharmacotherapy both on admission and after discharge from hospital. In-hospital mortality was very low in both genders, but 12-month mortality was significantly higher in women (10.8% vs. 3.0%; p = 0.003). Killip class 3 or 4 on admission (95% CI 19.6-288.4), age per 5-year increase (95% CI 1.01-3.73) and primary PCI (95% CI 0.1-0.93) affected mortality. In patients who underwent reperfusion there was moderately higher mortality in women than in men (7.1% vs. 1.9%; p = 0.046).

Conclusions

Despite little difference in the basic clinical characteristics and the management including a wide use of primary PCI, long-term mortality in women under forty after STEMI is significantly higher than in men.     

辛伐他汀促进模型大鼠心肌梗死后局部血管新生

目的 研究辛伐他汀对急性心肌梗死（AMI）后血管生成素-1（Ang-1）及内皮型一氧化氮合酶（eNOS）的表达调控与其促血管新生作用的关系。方法 健康成年SD大鼠60只,随机分为假手术组、对照组、辛伐他汀组、辛伐他汀+ L-NAME(NOS抑制剂)组、辛伐他汀+ AMG386 (Ang-1抑制剂)组;结扎大鼠冠状动脉左前降支建立急性心肌梗死动物模型。术后2 d分别给予辛伐他汀(1 mg/(kg·d) ),辛伐他汀+L-NAME(40 mg/(kg·d) ),辛伐他汀+AMG386（10 mg/(kg·wk）),均为2 周,以CD31染色新生血管并检测新生血管密度;以Western blot及RT-PCR检测缺血区心肌Ang-1、eNOS、丝氨酸1177磷酸化内皮型一氧化氮合酶(p-eNOS)的表达。结果（1）辛伐他汀使AMI后缺血区心肌新生血管密度显著增加（P<0.05 ）,而L-NAME 、AMG386则显著抑制了辛伐他汀的促心肌血管新生作用（P<0.05）。（2）辛伐他汀使AMI后缺血区心肌Ang-1、eNOS、p-eNOS表达均显著增强（P<0.05）,而AMG386使辛伐他汀上调p-eNOS表达的作用被显著抑制（P<0.05）。结论 辛伐他汀促心肌血管新生作用可能与其上调Ang-1、eNOS的表达及促进eNOS磷酸化有关,其中eNOS磷酸化可能是介导Ang-1促血管新生作用的下游机制。     

Effects on mortality during five years after early intervention with metoprolol in suspected acute myocardial infarction

This study reports the mortality over a 5-year-period determined a double-blind trial, which evaluated the effect of early intervention with metoprolol in suspected acute myocardial infarction. In all, there were 1,395 randomized patients, 698 and 697 of whom were allocated to metoprolol 200 mg daily and placebo treatments, respectively, for the first 3 months. Thereafter, the two groups were treated in a similar fashion implying beta-blockade to a majority. Within the first 3 months, mortality in the metoprolol group was 5.7% versus 8.9% of the placebo group (p = 0.02). This difference persisted after 2 years (metoprolol 13.2%; placebo 17.2%; p = 0.04). Over a 5-year-period, 24.2% of the patients who originally were allocated to metoprolol had died as compared to 25.7% of those originally allocated to placebo (p greater than 0.2). Among patients in whom treatment started early (less than or equal to 8 hours after onset of pain = the median delay time), enzyme activities in the metoprolol group was lower (p = 0.03) than in the placebo group. Mortality during the first 2 years among these patients treated early was lower in the metoprolol (11.8%) than in the placebo group (17.3%; p = 0.04). Corresponding figures after 5 years were 22.0% and 25.3%, respectively (p greater than 0.2). Among patients in whom treatment started later than 8 hours onset of pain, there was neither any difference in enzyme activity nor in mortality after 2 and 5 years. It can be concluded that early treatment with metoprolol in suspected acute myocardial infarction reduced mortality during the first 3 months compared with placebo. The difference persisted after 2 years. However, 5 years after randomization, no significant difference in mortality was observed between the two treatment groups.     

Sex dependent risk factors for mortality after myocardial infarction: individual patient data meta-analysis

Background

Although a number of risk factors are known to predict mortality within the first years after myocardial infarction, little is known about interactions between risk factors, whereas these could contribute to accurate differentiation of patients with higher and lower risk for mortality. This study explored the effect of interactions of risk factors on all-cause mortality in patients with myocardial infarction based on individual patient data meta-analysis.

Methods

Prospective data for 10,512 patients hospitalized for myocardial infarction were derived from 16 observational studies (MINDMAPS). Baseline measures included a broad set of risk factors for mortality such as age, sex, heart failure, diabetes, depression, and smoking. All two-way and three-way interactions of these risk factors were included in Lasso regression analyses to predict time-to-event related all-cause mortality. The effect of selected interactions was investigated with multilevel Cox regression models.

Results

Lasso regression selected five two-way interactions, of which four included sex. The addition of these interactions to multilevel Cox models suggested differential risk patterns for males and females. Younger women (age <50) had a higher risk for all-cause mortality than men in the same age group (HR 0.7 vs. 0.4), while men had a higher risk than women if they had depression (HR 1.4 vs. 1.1) or a low left ventricular ejection fraction (HR 1.7 vs. 1.3). Predictive accuracy of the Cox model was better for men than for women (area under the curves: 0.770 vs. 0.754).

Conclusions

Interactions of well-known risk factors for all-cause mortality after myocardial infarction suggested important sex differences. This study gives rise to a further exploration of prediction models to improve risk assessment for men and women after myocardial infarction.

     

Rehabilitation potential after myocardial infarction

For determination of the individual rehabilitation potential in patients after myocardial infarction, factors were extracted which are of importance for exercise capacity and its influence upon rehabilitation measures. Further results of exercise tests were correlated with psychological tests (Freiburg-personality-inventory) and the results of a patients' questionnaire for individual self-assessment, with concerning restitution by means of rehabilitation measures. 147 patients were admitted to a controlled rehabilitation program 10 weeks after myocardial infarction or later. Mean increase of exercise capacity after one year of rehabilitation was 21.6% of the initial test. Significantly greater increases of exercise capacity were achieved in patients with regular attendance particularly in younger patients in comparison with older patients. As evidenced by ergometric test data initially low maximal heart rate, low increase of heart rate, low exercise capacity and low double product were correlated with greater increase of exercise capacity. Patients with anterior-wall myocardial infarction tended to increased exercise capacity more. A relation between "psychosomatic disturbance" at onset of rehabilitation and a greater increase of exercise capacity could be determined as a trend. Connections between psychosocial factors and determinants of exercise capacity in influencing the rehabilitation potential are discussed.     

高雌激素血症对雌性心肌梗塞大鼠心肌舒缩性能的影响

本文研究了高雌激素血症对雌性心肌梗塞(MI)大鼠心肌舒缩性能的影响。结果:(1)MI组血浆雌二醇(E_2)先略升高而后降低,雌二醇处理MI组(MIE_2)血浆雌二醇明显升高。(2)MIE_2组心肌纤维直径比对照假手术组(CS)及MI组显著增大(10.65±0.59 VS 7.65±0.40及10.15±0.54gm,P<0.001,<0.02)。(3)两MI组的LVSP、±dp/dt max均显著降低,T-值明显延长,尤以MIE_2组更为显著(10.5±4.1 VS 6.2±4.6ms,P<0.02)。(4)两MI组动脉压显著降低,HR减慢,LVET延长;在9天观测点,MIE_2组的HR仍较MI组显著减慢、LVET明显延长。提示高雌激素血症可使雌性心肌梗塞大鼠心肌舒缩性能降低。