Prognostic value of prolonged ventricular repolarization following myocardial infarction: the BHAT experience. The BHAT Study Group

In the Beta Blocker Heart Attack Trial (BHAT), 3837 patients were randomized to propranolol (180-240 mg/day) or placebo 5-21 days after a documented myocardial infarction and were followed in a double blind manner for a mean period of 25 months. Twelve lead electrocardiograms were routinely obtained at the time of randomization (baseline electrocardiogram) and at 12 and 24 months of follow-up. There was a positive correlation between baseline QTc interval prolongation (but not QT prolongation) and mortality and sudden death that was independent of treatment group. The data for non-sudden death and non-fatal reinfarction exhibit similar trends. We conclude that: (1) QTc prolongation identifies a high risk subset of post myocardial infarction patients. (2) The relative benefit of propranolol is similar in patients with normal and prolonged QTc.     

The prognostic value of the duration of the ambulatory electrocardiogram after myocardial infarction

The purpose of this study was to examine the value of various durations of ambulatory ECG recording with regard to providing useful prognostic information. The authors explored a decision theoretic approach to determine the most useful period of monitoring for making a treatment decision based upon postulated benefit-to-risk ratios of antiarrhythmic therapies. They used data collected as part of the Beta-Blocker Heart Attack Trial (BHAT), a randomized clinical trial of propranolol versus placebo in 3,837 post-myocardial-infarction patients. In BHAT, 1,336 placebo-treated patients had a 24-hour ambulatory ECG that had at least 23 readable hours. Sensitivity and specificity were calculated for eight definitions of ventricular arrhythmia using either total mortality or sudden death (death within one hour of symptoms) as an endpoint. These indices were obtained using the first 1, 2, 4, 6, 12, and 24 hours plus a random hour, a random daytime hour, and a random nighttime hour of the 24-hour ECG of 1,336 placebo-treated patients. The study showed that in the case of high-risk, low-benefit therapies, no test is needed to make a treatment decision. No one should be treated. In the case of high-benefit, low-risk therapies, again, no test is required. Everyone should be treated. For therapies in the middle benefit-to-risk ratio range the most appropriate test for a treatment decision changes from the very specific to the most sensitive. Twenty-four hours of ambulatory monitoring is usually not necessary for a treatment decision, since four hours is likely to be sufficient.     

Assessment of angina pectoris after myocardial infarction: comparison of "Rose Questionnaire" with physician judgment in the Beta-Blocker Heart Attack Trial

The London School of Hygiene Cardiovascular Questionnaire (Rose Questionnaire) was compared with physician opinion in assessment of angina pectoris in the Beta-Blocker Heart Attack Trial, a long-term (June 1978-October 1981), multicenter study of 3,837 post-myocardial infarction patients, half of whom were treated with propranolol and half with placebo. At baseline, about three times as many patients were thought to have angina by the physician as were diagnosed by the Questionnaire (36.1% vs. 11.5%). Over the average 25-month follow-up period, angina was identified by the physician 50% more often than by the Questionnaire (60.3% vs. 38.6%). The results for each treatment group (propranolol or placebo) were very similar to these overall results. Associations between diagnosis of angina and other patient characteristics were similar for the two measures at baseline. Although the physician diagnosis of angina identified more patients who suffered a subsequent fatal or nonfatal event than did the Questionnaire, it also diagnosed more angina patients who did not have an event. Thus, each of the measures of angina predicted total mortality and coronary heart disease mortality to similar extents (comparable relative risks), even after adjustment for covariates. Neither measure was significantly predictive of recurrent nonfatal myocardial infarction. One measure is not clearly superior to the other in this population. Other factors, such as cost and type of personnel available to conduct the study, may determine which measure is preferred.     

Statistical methods that distinguish between attributes of assessment: prolongation of life versus quality of life.

The authors propose a method to generate information relevant to the decision tree that adds additional perspective to the characterization of health quality during survival. Their approach uses survival data to distinguish two attributes of utility: prolongation of life and quality of life (QOL). Health-state transition probabilities correspond to the prolongation of life and are modeled in a discrete-time transient semi-Markov process. Quality-of-life-state transition probabilities are derived from the assumptions of a simple recurrent Markov process. They reflect events within the health-state sojourn time that differentiate perceptions of pain and suffering over a short fixed time period. Outcomes for these two dimensions of utility are highly relevant to the assessment of medical technology that might prolong life at the cost of increased pain and suffering, implying a reduced QOL. The methods are demonstrated on a subset of follow-up data from the Beta-Blocker Heart Attack Trial (BHAT).     

Practical aspects in data monitoring: a brief review

Monitoring interim accumulating data in a clinical trial for evidence of therapeutic benefit or toxicity is a frequent policy, usually carried out by an independent scientific committee. Repeated testing at conventional critical values can substantially inflate the type I error rate. To maintain acceptable levels, group sequential and stochastic curtailment have been developed for clinical trials. One should not view such methods as absolute rules, but as useful guides. The decision process to terminate a trial early is complex and necessitates an accounting for many factors. The Beta-Blocker Heart Attack Trial provides an excellent example of many of these issues.     

Antiarrhythmic short-term protective magnesium treatment in ischemic dilated cardiomyopathy.

The efficacy of magnesium sulfate (MgSO4) infusion in the treatment of ventricular arrhythmias was evaluated in 10 normomagnesemic patients: seven men and three women, aged 56-78 years (mean +/- SD, 63.8 +/- 9.3). All of the patients had ischemic dilated cardiomyopathy (IDC) and severe ventricular arrhythmias: multiform ventricular premature contractions (VPCs), couplets, runs of ventricular tachycardia (VT), and R-on-T phenomenon. Four had evidence of old myocardial infarction (MI), four had chronic ischemic cardiomyopathy, and two had effort angina pectoris. Dilated cardiomyopathy was diagnosed by chest X-ray (cardiothoracic ratio greater than 0.5) and echocardiogram (end-diastolic left-ventricular diameter greater than 56 mm). All of the patients underwent two successive 24-hr Holter monitoring at the time of admission and after 3, 5, and 10 days from the beginning of therapy. Ventricular arrhythmias were classified according to modified Lown criteria. Renal function was normal. Magnesium sulfate in 0.9% sodium chloride was given by slow infusions (50 mg/min/60 min) twice daily for 7 days. They were antiarrhythmic in all of the patients: VPCs and couplets mean values decreased from 7971 +/- 2612 to 321 +/- 141 (p less than 0.001) and from 405 +/- 113 to 7 +/- 4 (p less than 0.001), respectively; VT runs (33.8 +/- 5.8) disappeared by the fifth day of treatment. Both the heart rate and the QTc interval remained unchanged from baseline values. The slow magnesium infusion did not notably raise serum Mg when evaluated immediately after stopping the infusion, as compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antiarrhythmic short-term protective magnesium treatment in ischemic dilated cardiomyopathy

The efficacy of magnesium sulfate (MgSO4) infusion in the treatment of ventricular arrhythmias was evaluated in 10 normomagnesemic patients: seven men and three women, aged 56-78 years (mean +/- SD, 63.8 +/- 9.3). All of the patients had ischemic dilated cardiomyopathy (IDC) and severe ventricular arrhythmias: multiform ventricular premature contractions (VPCs), couplets, runs of ventricular tachycardia (VT), and R-on-T phenomenon. Four had evidence of old myocardial infarction (MI), four had chronic ischemic cardiomyopathy, and two had effort angina pectoris. Dilated cardiomyopathy was diagnosed by chest X-ray (cardiothoracic ratio greater than 0.5) and echocardiogram (end-diastolic left-ventricular diameter greater than 56 mm). All of the patients underwent two successive 24-hr Holter monitoring at the time of admission and after 3, 5, and 10 days from the beginning of therapy. Ventricular arrhythmias were classified according to modified Lown criteria. Renal function was normal. Magnesium sulfate in 0.9% sodium chloride was given by slow infusions (50 mg/min/60 min) twice daily for 7 days. They were antiarrhythmic in all of the patients: VPCs and couplets mean values decreased from 7971 +/- 2612 to 321 +/- 141 (p less than 0.001) and from 405 +/- 113 to 7 +/- 4 (p less than 0.001), respectively; VT runs (33.8 +/- 5.8) disappeared by the fifth day of treatment. Both the heart rate and the QTc interval remained unchanged from baseline values. The slow magnesium infusion did not notably raise serum Mg when evaluated immediately after stopping the infusion, as compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Height and mortality after myocardial infarction

A case-control analysis was conducted to determine the relationship between height and mortality among patients enrolled in the already completed Beta Blocker Heart Attack Trial (BHAT). In a basic model including height (continuous) and relevant covariates the relative risk (RR) per 4-inch reduction in height (approximately 1 standard deviation) was 1.18 (95% confidence interval, 0.92 to 1.51). When sex was considered, the effect of short stature on mortality was found to be restricted to male subjects. The male RR per 4-inch reduction in height was 1.26 (0.96 to 1.63) whereas for women it was 0.89 (0.49 to 1.59). In males not randomized to propranolol (untreated) the effect was further modified with a RR per 4-inch reduction in height of 1.41 (1.00 to 1.99). It is hypothesized that short stature could be a marker for factors operating as far back as childhood that predispose males to mortality from coronary heart disease in later life.This study was supported by research grants HL39641 and MR00096 from the National Institutes of Health. Funds for a pilot study were provided by the Henry L. Goldberg Foundation. We wish to express our gratitude to Bert Holland for computer assistance.     

Quality of life among patients post-myocardial infarction at baseline in the Survival and Ventricular Enlargement (SAVE) trial

A quality of life ancillary study was incorporated into the Survival and Ventricular Enlargement (SAVE) trial of captopril versus placebo among patients who survived an acute myocardial infarction with compromised ventricular functioning, but no overt heart failure. Assessments included patient symptoms, health perceptions, emotional, cognitive, social and sexual levels of functloning, as well as potential covariates, such as life events and social support. The purpose of this study was to evaluate the psychometric properties of the quality of life measures in the SAVE at baseline, and provide a pre-randomization profile of the SAVE patients. One hundred and eighty-four patients participated in this aspect of the trial. Reliability alpha coefficlents were adequate or better for all questionnaires, except for life events and sexual activities. Consistent with prior studies, the quality of life parameters were uncorrelated with ventricular ejection fraction. Despite experiencing a recent myocardial infarction with compromised ventricular functioning, patients at baseline generally nelther appeared depressed nor focused on symptoms. The baseline findings support the inclusion of the quality of life ancillary study in the overall SAVE trial because of the independent contribution likely to be achieved in terms of evaluating both disease progression and treatment efficacy.Supported in part by a grant provided by the Bristol-Myers Squibb Co.     

Impact of community-based education on health care evaluation in patients with acute chest pain syndromes: the Wabasha Heart Attack Team (WHAT) project

BACKGROUND: Community education programmes focused on raising public awareness of the symptomatology of acute coronary syndromes have had mixed results. OBJECTIVES: The Wabasha Heart Attack Team project, a unique multidisciplinary public education effort in Minnesota, sought to educate area citizens about signs and symptoms of acute myocardial infarction (MI). METHODS: After an intensive 1-month education period, we compared presentations for emergency evaluation of chest pain during the study period with baseline data from the same seasonal period of the preceding year. RESULTS: Visits to the Emergency Room for symptomatic heart disease increased significantly during the study period (56 patients versus 46 patients during the baseline period), as did the percentage of patients presenting with acute MI (18% versus 12%, P < 0.05). Use of emergency medical services for pre-hospital evaluation was significantly increased (41% versus 27%, P < 0.05). CONCLUSION: A community education campaign can significantly increase use of pre-hospital emergency medical service resources and may increase the number of patients presenting with acute chest pain symptoms, including MI.     

二维斑点追踪超声心动图测量的应变参数在预测心脏节段功能恢复及左心室重构中的价值

目的探讨二维斑点追踪超声心动图测量的应变参数在预测心脏节段功能恢复及左心室重构中的价值。方法回顾性分析2018年1月至2019年2月医院收治的350例初发急性ST段抬高型心肌梗死患者的临床资料,全部患者在心肌梗死的24 h内接受心脏超声检查,冠脉造影后行经皮冠脉介入术(PCI)治疗,术后6个月复查心脏超声。结果随访后,功能恢复节段基线具备的应变参数绝对值高于功能无明显改变的节段(P<0.05);相较于预后良好组与无左心室重构组,预后不良组与左心室重构组的E/e’比值、室壁运动评分较高,左心室射血分数较低;当整体环周应变在-17.48%及以上时,对左心室重构进行预测的AUC最大。结论二维斑点追踪超声心动图应变参数可对心肌梗死后心脏节段功能恢复及左心室重构进行有效预测。     

急性心肌梗死再通后心电图演变与心功能的关系

目的探讨ST段抬高型急性心肌梗死急诊介入治疗（PCI）后心电图ST段和T波演变与左心功能的关系。方法选择初发ST段抬高型急性心肌梗死并行急诊PCI术的患者72例，按术后1hST段是否回落≥50％和24hT波是否倒置各分为两组。术后1h ST段回落≥50％组48例，〈50％组24例，发病后24hT波倒置组50例，未倒置组22例。随访6个月，分别于1个月和6个月时测量心功能。用三维彩色多普勒技术测量左室射血分数（LVEF）和左室舒末内径（LVD），用多普勒心肌组织显像技术（DTI）测量并计算Em／Am。比较左心功能恢复情况。结果1个月时ST段早期凹落组和T波早期倒置组LVEF、Em／Am值分别高于ST段未回落组和T波未倒置组（P〈0．05），而LVD无明显差异（P〉0．05）。6个月时ST段早期回落组和T波早期倒置组LVEF、Em／Am值均高于ST段未回落组和T波未倒置组（P〈0．05），ST段早期回落组和T波早期倒置组LVD值小于sT段未回落组和T波未倒置组（P〈0．05）。结论急诊PCI术后1h内ST段早期回落和24hT波早期倒置是反映左心功能恢复良好的指标。     

Heterogeneity in randomized controlled trials of long chain (fish) omega-3 fatty acids in restenosis, secondary prevention and ventricular arrhythmias

Randomized controlled trials of marine omega-3 fatty acid supplementation in relation to coronary heart disease (CHD) have inconsistent outcomes, yet public health messages are uniformly positive. Originally, fish were seen as a low saturated fat protein source, and later as a valuable source of omega-3 fatty acids. Early trials indicated that increased fish oil consumption prevented restenosis after coronary angioplasty. Later trials demonstrated that fish oils prolonged life post myocardial infarction (MI). Currently, the potential antiarrhythmic effects of fish derived omega-3 fatty acids are seen as the primary reason for cardiac benefits, as suggested by one trial with compliant subjects with implantable cardioverter defibrillators (ICDs), and sudden death reduction in a post MI trial. However, the earlier benefits of EPA and DHA on restenosis have only been confirmed in a subgroup in a recent meta-analysis. Newer data indicate that fish oils may increase CHD events in men with angina. Furthermore, in two of three trials in patients with ICDs and a history of ventricular arrhythmias, fish oils showed no significant benefit or even increased the risk of appropriate ICD discharge. Certain groups of individuals may benefit from long-chain omega-3 fatty acids while others, including men with angina and some individuals with a history of ventricular arrhythmia, may not. Due to significant heterogeneity in the response to fish oils, further studies are required before making widespread recommendations for all groups to increase consumption of fish and fish oil.     

Heterogeneity in Randomized Controlled Trials of Long Chain (Fish) Omega-3 Fatty Acids in Restenosis,Secondary Prevention and Ventricular Arrhythmias

Randomized controlled trials of marine omega-3 fatty acid supplementation in relation to coronary heart disease (CHD) have inconsistent outcomes, yet public health messages are uniformly positive. Originally, fish were seen as a low saturated fat protein source, and later as a valuable source of omega-3 fatty acids. Early trials indicated that increased fish oil consumption prevented restenosis after coronary angioplasty. Later trials demonstrated that fish oils prolonged life post myocardial infarction (MI). Currently, the potential antiarrhythmic effects of fish derived omega-3 fatty acids are seen as the primary reason for cardiac benefits, as suggested by one trial with compliant subjects with implantable cardioverter defibrillators (ICDs), and sudden death reduction in a post MI trial.

However, the earlier benefits of EPA and DHA on restenosis have only been confirmed in a subgroup in a recent meta-analysis. Newer data indicate that fish oils may increase CHD events in men with angina. Furthermore, in two of three trials in patients with ICDs and a history of ventricular arrhythmias, fish oils showed no significant benefit or even increased the risk of appropriate ICD discharge.

Certain groups of individuals may benefit from long-chain omega-3 fatty acids while others, including men with angina and some individuals with a history of ventricular arrhythmia, may not. Due to significant heterogeneity in the response to fish oils, further studies are required before making widespread recommendations for all groups to increase consumption of fish and fish oil.     

Present-at-admission diagnoses improved mortality risk adjustment among acute myocardial infarction patients

OBJECTIVE: Hospital mortality outcomes for acute myocardial infarction (AMI) patients are a focus of quality improvement programs conducted by government agencies. AMI mortality risk-adjustment models using administrative data typically adjust for baseline differences in mortality risk with a limited set of common and definite comorbidities. In this study, we present an AMI mortality risk-adjustment model that adjusts for comorbid disease and for AMI severity using information from secondary diagnoses reported as present at admission for California hospital patients. STUDY DESIGN AND SETTING: AMI patients were selected from California hospital administrative data for 1996 through 1999 according to criteria used by the California Hospital Outcomes Project Report on Heart Attack Outcomes, a state-mandated public report that compares hospital mortality outcomes. We compared results for the new model to two mortality risk-adjustment models used to assess hospital AMI mortality outcomes by the state of California, and to two other models used in prior research. RESULTS: The model using present-at-admission diagnoses obtained substantially better discrimination between predicted survival and inpatient death than the other models we considered. CONCLUSION: AMI mortality risk-adjustment methods can be meaningfully improved using present-at-admission diagnoses to identify comorbid disease and conditions related closely to AMI.     

急性心肌梗死合并心律失常应用心电监护仪的效果观察

目的:观察并分析心电监护仪在急性心肌梗死合并心律失常患者中的应用效果。方法:将本院自2017年11月~2019年3月收治的114例急性心肌梗死患者作为临床观察对象,采取随机数字表法将所有患者随机分为两组。观察组(57例)采用心电监护仪进行监测,对照组(57例)采取常规监测,对两组患者不同时间段内的心率失常发生情况、室早、室速或室颤、Ⅱ或Ⅲ度房室传导阻滞、窦性停搏等发生率进行观察和统计。结果:观察组患者室早、室速或室颤、Ⅱ或Ⅲ度房室传导阻滞、窦性停搏等发生率与对照组患者比较明显更低,P<0.05;观察组患者不同时间段内的心律失常发生率与对照组患者比较均更低,且总心律失常发生率明显更低,P<0.05。结论:将心电监护仪应用于急性心肌梗死患者监测中,不仅可以有效减少心律失常发生的情况,还可以降低室早、室速或室颤、Ⅱ或Ⅲ度房室传导阻滞、窦性停搏等发生率。     

右心室心肌梗死的临床诊断与治疗分析

目的探讨右心室心肌梗死有效的临床诊断及治疗方法。方法随机抽取50例因右心室心肌梗死就患者的临床资料进行回顾性分析。结果本组50例患者中抢救无效死亡3例占6％,其他患者均抢救成功。结论通过无创性检查、诊断及监测措施判定患者的病情变化,并在此基础上给予大量补液及参脉注射液能够有效治疗右心室心肌梗死。     

Evaluation of a public education program delivered by firefighters on early recognition of a heart attack

The Heart Attack Survival Kit (HASK) project is a prospective, randomized trial, testing the effectiveness of an intervention delivered door-to-door by firefighters to increase use of 911 and ingestion of aspirin for symptoms of acute myocardial infarction (AMI) among seniors in King County, Washington. Firefighters visited 24,582 seniors in King County, Washington and delivered a Heart Attack Survival Kit. Another 24,191 senior households served as the control group. Outcomes of the program were measured by tracking 911 calls as well as survey data. This study reports on the results of the telephone survey with a random sample of seniors (N = 323) to assess their knowledge of and intentions to act during a heart emergency. Results of a logistic regression analysis showed that being female, being younger, and remembering the kit was significantly related to intentions to act appropriately to AMI symptoms. The results are discussed in terms of public education around AMI.     

零膨胀模型在心肌缺血节段数影响因素研究中的应用

目的讨论零膨胀模型在计数资料中的应用。方法应用零膨胀负二项模型分析冠心病患者心肌缺血节段数的影响因素。结果零膨胀负二项模型logit部分结果表明没有家族史、年龄越小、左室收缩末容积越小的患者发生心肌节段缺血的可能性较小;负二项部分结果表明有糖尿病史、有冠心病家族史、左室收缩末容积越大的患者发生心肌缺血节段数越多。结论当计数资料存在过多零计数时,应用零过多模型能够得到很好的拟合效果。     

猪急性心肌梗死后骨髓干细胞自体移植对左心室重构的影响

目的 观察猪心肌梗死(心梗)后冠脉内注射移植骨髓干细胞时心室重_构的影响.方法 前降支球囊封堵法成功建立10头猪急性心肌梗死动物模型,随机均分为安慰刺组和移植组.造模1周后,移植组冠脉内注自体骨髓干细胞,安慰剂组注射1640培养基作为对照.造模前、造模后1周、造模后3月分别行心脏超声和SPECT检查,对比观察骨髓干细胞自体移植对急性心梗后左室重构的影响.结果与安慰剂组相比,移植组造模后3月时左室舒张内径更小,心尖室壁厚度更大,左室舒张末期容积更小,射血分数更高.结论 骨髓干细胞自体移植能有效减轻急性心肌梗死后左室重构.