Decreased incidence of ventricular late potentials after successful thrombolytic therapy for acute myocardial infarction

In some patients with acute myocardial infarction, low-amplitude potentials that prolong the QRS complex, termed "late potentials," can be recorded on a signal-averaged electrocardiogram. The presence of these late potentials is known to be associated with an increase in the risk of ventricular tachycardia and sudden death. Because patients with acute myocardial infarction who receive thrombolytic therapy have a reduced incidence of ventricular tachyarrhythmia and sudden death, we sought to determine whether such patients also have a decreased incidence of late potentials. We studied 106 patients less than 75 years of age who were admitted with a first myocardial infarction and in whom a signal-averaged electrocardiogram was recorded within 48 hours of admission. Within four hours of the onset of chest pain, tissue plasminogen activator (t-PA) was given to 44 patients, and 62 were treated conventionally. In the t-PA group, late potentials were recorded in 2 of 44 patients (5 percent), as compared with 14 of 62 (23 percent) in the conventionally treated group (P = 0.01). Furthermore, among the patients treated with t-PA, continued occlusion of the infarct-related artery was related to the presence of late potentials. In the t-PA group, late potentials were recorded within 24 hours of angiography in 2 of the 6 patients with an occluded infarct-related artery, as compared with none of the 38 patients with a patient infarct-related artery. Our data suggest that successful thrombolytic therapy is associated with a marked reduction in the incidence of late potentials on the signal-averaged electrocardiogram. Long-term follow-up will be required to determine whether this finding predicts a reduced incidence of subsequent ventricular tachyarrhythmia and sudden death.     

Cardiogenic shock after acute myocardial infarction. Incidence and mortality from a community-wide perspective, 1975 to 1988

BACKGROUND. Cardiogenic shock resulting from acute myocardial infarction is a serious complication with a high mortality rate, but little is known about whether its incidence or outcome has changed over time. As part of an ongoing population-based study of acute myocardial infarction, we examined trends over time in the incidence and mortality rate of cardiogenic shock after acute myocardial infarction. METHODS. We studied 4762 patients with acute myocardial infarction who were admitted to 16 hospitals in the Worcester, Massachusetts, metropolitan area between 1975 and 1988. We determined the incidence of and short-term and long-term mortality due to cardiogenic shock in each of six years during this study period. RESULTS. The incidence of cardiogenic shock complicating acute myocardial infarction remained relatively constant, averaging 7.5 percent. Multivariate regression analysis that controlled for variables affecting incidence revealed significant though inconsistent temporal trends in the incidence of cardiogenic shock. As compared with the risk in 1975, the adjusted relative risk (with 95 percent confidence interval) was 0.83 (0.54 to 1.28) in 1978, 0.96 (0.63 to 1.48) in 1981, 0.68 (0.42 to 1.12) in 1984, 1.16 (0.70 to 1.92) in 1986, and 1.65 (0.99 to 2.77) in 1988. The overall in-hospital mortality rate among patients with cardiogenic shock was significantly higher than that among patients without this complication (77.7 percent vs. 13.5 percent, P less than 0.001). The in-hospital mortality among the patients with shock did not improve between 1975 (73.7 percent) and 1988 (81.7 percent). Long-term survival during the 14-year follow-up period was significantly worse among patients who survived cardiogenic shock during hospitalization than among patients who did not have shock (P less than 0.001). CONCLUSIONS. The results of this observational, community-wide study suggest that neither the incidence nor the prognosis of cardiogenic shock resulting from acute myocardial infarction has improved over time. Both in-hospital and long-term survival remain poor for patients with this complication.     

The association between hospital volume and survival after acute myocardial infarction in elderly patients.

BACKGROUND: Patients with chest pain thought to be due to acute coronary ischemia are typically taken by ambulance to the nearest hospital. The potential benefit of field triage directly to a hospital that treats a large number of patients with myocardial infarction is unknown. METHODS: We conducted a retrospective cohort study of the relation between the number of Medicare patients with myocardial infarction that each hospital in the study treated (hospital volume) and long-term survival among 98,898 Medicare patients 65 years of age or older. We used proportional-hazards methods to adjust for clinical, demographic, and health-system-related variables, including the availability of invasive procedures, the specialty of the attending physician, and the area of residence of the patient (rural, urban, or metropolitan). RESULTS: The patients in the quartile admitted to hospitals with the lowest volume were 17 percent more likely to die within 30 days after admission than patients in the quartile admitted to hospitals with the highest volume (hazard ratio, 1.17; 95 percent confidence interval, 1.09 to 1.26; P<0.001), which resulted in 2.3 more deaths per 100 patients. The crude mortality rate at one year was 29.8 percent among the patients admitted to the lowest-volume hospitals, as compared with 27.0 percent among those admitted to the highest-volume hospitals. There was a continuous inverse dose-response relation between hospital volume and the risk of death. In an analysis of subgroups defined according to age, history of cardiac disease, Killip class of infarction, presence or absence of contraindications to thrombolytic therapy, and time from the onset of symptoms, survival at high-volume hospitals was consistently better than at low-volume hospitals. The availability of technology for angioplasty and bypass surgery was not independently associated with overall mortality. CONCLUSIONS: Patients with acute myocardial infarction who are admitted directly to hospitals that have more experience treating myocardial infarction, as reflected by their case volume, are more likely to survive than are patients admitted to low-volume hospitals.     

Effect of intravenous streptokinase on left ventricular function and early survival after acute myocardial infarction

In a double-blind trial of streptokinase for acute myocardial infarction, 219 consecutive patients presenting with infarction within four hours (mean, 3.0 +/- 0.8) of the onset of chest pain were randomly assigned to treatment with streptokinase (1.5 million units) or placebo, given intravenously over 30 minutes. The primary end point of the study was left ventricular function in patients with first infarctions. Patients who could undergo beta-blockade also received intravenous propranolol. Heparin (for 48 hours) and a combination of low-dose aspirin and dipyridamole were administered to both groups until cineangiography was performed at three weeks. In the patients with first infarctions treated with streptokinase, the left ventricular ejection fraction was 6 percentage points higher (streptokinase vs. placebo, 59 +/- 10.5 vs. 53 +/- 13.5 percent; P less than 0.005), with benefit to patients with either anterior infarction (57 +/- 11.9 vs. 49 +/- 15.9 percent; P less than 0.05) or inferior infarction (60 +/- 9.1 vs. 55 +/- 11.3 percent; P less than 0.05). Left ventricular function was improved regardless of whether concomitant propranolol was given. Survival (at 30 days) was improved with streptokinase: 2 deaths occurred among 79 patients who received this drug, as compared with 12 deaths among 93 patients who received placebo (2.5 vs. 12.9 percent, P = 0.012). Rates of reinfarction (streptokinase vs. placebo, 3 vs. 1 percent) and requirements for surgery or angioplasty (7 vs. 5 percent) were similar in the two groups. We conclude that administration of intravenous streptokinase (1.5 million units) to patients with a first myocardial infarction results in improved left ventricular function and short-term survival.     

Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban.

BACKGROUND: There is continued debate as to whether a routine, early invasive strategy is superior to a conservative strategy for the management of unstable angina and myocardial infarction without ST-segment elevation. METHODS: We enrolled 2220 patients with unstable angina and myocardial infarction without ST-segment elevation who had electrocardiographic evidence of changes in the ST segment or T wave, elevated levels of cardiac markers, a history of coronary artery disease, or all three findings. All patients were treated with aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. They were randomly assigned to an early invasive strategy, which included routine catheterization within 4 to 48 hours and revascularization as appropriate, or to a more conservative (selectively invasive) strategy, in which catheterization was performed only if the patient had objective evidence of recurrent ischemia or an abnormal stress test. The primary end point was a composite of death, nonfatal myocardial infarction, and rehospitalization for an acute coronary syndrome at six months. RESULTS: At six months, the rate of the primary end point was 15.9 percent with use of the early invasive strategy and 19.4 percent with use of the conservative strategy (odds ratio, 0.78; 95 percent confidence interval, 0.62 to 0.97; P=0.025). The rate of death or nonfatal myocardial infarction at six months was similarly reduced (7.3 percent vs. 9.5 percent; odds ratio, 0.74; 95 percent confidence interval, 0.54 to 1.00; P<0.05). CONCLUSIONS: In patients with unstable angina and myocardial infarction without ST-segment elevation who were treated with the glycoprotein IIb/IIIa inhibitor tirofiban, the use of an early invasive strategy significantly reduced the incidence of major cardiac events. These data support a policy involving broader use of the early inhibition of glycoprotein IIb/IIIa in combination with an early invasive strategy in such patients.     

非ST段改变的急性心肌梗死临床分析

目的 探讨非ST段改变的急性心肌梗死患者冠状动脉病变情况,指导进一步治疗。方法 选取我院2013年12月~2018年12月因胸闷、胸痛不适入住苏州高新区人民医院、新疆自治区人民医院的患者76例,入院行心电图未见相关导联ST段改变,动态观察心电图及血清超敏肌钙蛋白T、肌酸激酶同工酶,多次复查未发现心电图有动态改变,但血清超敏肌钙蛋白、肌酸激酶同工酶数小时,甚至更长时间开始升高,急诊行冠状动脉造影术（CAG）,观察有无冠状动脉急性闭塞或次全闭塞,同时观察病变冠脉血管的部位、内径。结果 纳入的76例心电图无ST段改变,但数小时后血清心肌标志物升高的胸闷、胸痛患者行冠状动脉造影术发现:冠状动脉急性闭塞或次全闭塞的患者占94.74%,比例较高,多见于钝缘支,占78.95%,且冠脉血管内径均＞1.5 mm。结论 除了ST段抬高和ST段压低的急性心肌梗死,非ST段改变的急性心肌梗死也常常出现在临床当中,对此类不典型的患者,早期识别很重要,及时有效的处理,预后良好。     

Multicenter evaluation of h-FABP semi-quantitative assay (Cardio Detect) in central laboratory: the point in acute myocardial infarction diagnosis

The diagnostic performance of heart-Fatty Acid Binding Protein (h-FABP) (semi-quantitative CardioDetect test) and cardiac troponin I (TnIc) blood assays were compared in one hundred patients presenting with suspicion of acute coronary syndrome. Final patient diagnosis was "acute myocardial infarction" in 36 cases, "non ST myocardial infarction" in 25 cases and "non ischemic pathologies" in 39 cases. h-FABP results were positive in 26 patients, negative in 57 patients and ambiguous in 17 patients, the latter corresponding to the final diagnosis of "acute myocardial infarction" in 5 cases, "non ST myocardial infarction" in 2 cases and "non ischemic pathologies " in 10 cases. At admission, h-FABP and TnIc exhibiteda sensitivity of 54% an 66%, respectively and a specificity of 86% and 95%, respectively. Positive and negative predictive values were 81% and 64% for h-FABP, respectively and 92% and 75% for cTnI, respectively. h-FABP and cTnI demonstrated a similar diagnostic efficiency if admission delay is less than 4 hours after onset of chest pain (area under ROC curve TnIc = 0.767 +/- 0.091 ; area under ROC curve h-FABP = 0.622 +/- 0.109 ; p = 0.144). On the contrary, cTnI assay demonstrated a better efficiency than h-FABP (p< 0.005) for patients admitted in a delay of 4 to 12 hours after the onset of chest pain. If chosen cTnI cut-off corresponded to the recent consensus definition used for monitoring acute coronary syndrome patients, h-FABP semi-quantitative assay realized within central laboratory did not demonstrated a better diagnostic efficiency than cTnI.     

Patients with suspected myocardial infarction: effect of mode of referral on admission time to a coronary care unit.

The aim of this prospective study was to determine the delay between the onset of symptoms and arrival in the coronary care unit of patients with suspected acute myocardial infarction, and the relative contribution to the total delay of patient delay, method of referral (self referral or general practitioner referral) and delay in the hospital before reaching the coronary care unit. All patients admitted with chest pain to the coronary care unit at Dudley Road Hospital, Birmingham, over the six month period April-September 1989 were included in the study. Ninety five patients were referred by their general practitioner and 107 patients attended the accident and emergency department directly or arrived by ambulance without contacting their general practitioner. The proportion of self referred and general practitioner referred patients with acute myocardial infarction, angina and non-cardiac chest pain were not significantly different. The total delay was significantly longer for patients who had been referred by their general practitioner (median 5.3 hours) than for self referrals (3.2 hours, P less than 0.001), with a significantly higher proportion of self referrals arriving at the coronary care unit within six hours of the onset of symptoms (77% versus 54%, P less than 0.01). Among general practitioner referrals, initial patient delay accounted for a median of 2.5 hours and the general practitioner's response time for a median of 1.1 hours. The delay in hospital was similar for both groups of patients. In inner city areas, self referral may result in considerably less delay than general practitioner referral allowing a greater proportion of patients to receive effective thrombolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the early administration of enalapril on mortality in patients with acute myocardial infarction. Results of the Cooperative New Scandinavian Enalapril Survival Study II (CONSENSUS II)

BACKGROUND. Long-term administration of angiotensin-converting--enzyme (ACE) inhibitors has been shown to improve survival in patients with symptomatic left ventricular failure and to attenuate left ventricular dilatation in patients with myocardial infarction. We studied whether mortality could be reduced during the 6 months after an acute myocardial infarction with use of the ACE inhibitor enalapril. METHODS. At 103 Scandinavian centers patients with acute myocardial infarctions and blood pressure above 100/60 mm Hg were randomly assigned to treatment with either enalapril or placebo, in addition to conventional therapy. Therapy was initiated with an intravenous infusion of enalapril (enalaprilat) within 24 hours after the onset of chest pain, followed by administration of oral enalapril. RESULTS. Of the 6090 patients enrolled, 3046 were assigned to placebo and 3044 to enalapril. The life-table mortality rates in the two groups at one and six months were not significantly different (6.3 and 10.2 percent in the placebo group vs. 7.2 and 11.0 percent in the enalapril group, P = 0.26). The relative risk of death in the enalapril group was 1.10 (95 percent confidence interval, 0.93 to 1.29). Death due to progressive heart failure occurred in 104 patients (3.4 percent) in the placebo group and 132 (4.3 percent) in the enalapril group (P = 0.06). Therapy had to be changed because of worsening heart failure in 30 percent of the placebo group and 27 percent of the enalapril group (P less than 0.006). Early hypotension (systolic pressure less than 90 mm Hg or diastolic pressure less than 50 mm Hg) occurred in 12 percent of the enalapril group and 3 percent of the placebo group (P less than 0.001). CONCLUSIONS. Enalapril therapy started within 24 hours of the onset of acute myocardial infarction does not improve survival during the 180 days after infarction.     

Cost effectiveness of thrombolytic therapy with streptokinase in elderly patients with suspected acute myocardial infarction.

BACKGROUND. There is a lack of consensus among cardiologists about the potential benefit of thrombolytic therapy for suspected acute myocardial infarction in older patients. To investigate this issue, we constructed a decision-analytic model for patients 75 years of age or older who present with ST-segment elevation within six hours of the onset of symptoms suggesting acute myocardial infarction. METHODS. The variables incorporated in this model were the probability that the patient has an acute myocardial infarction, the probability of in-hospital death among patients with acute myocardial infarction who do not receive thrombolytic therapy, the probability of a fatal or incapacitating complication resulting from thrombolytic therapy, and the expected relative reduction in the risk of death associated with thrombolytic therapy in patients with acute myocardial infarction. Our analyses were based primarily on the use of streptokinase as the thrombolytic agent. RESULTS. Given our base-line assumptions, the probability of dying in the hospital was 21.4 percent if thrombolytic therapy was given and 24.4 percent if it was not given. In one-way sensitivity analyses, thrombolytic therapy decreased the risk of dying if the probability that the patient had an acute myocardial infarction was assumed to be greater than 9 percent, if the probability of dying in the hospital after an acute myocardial infarction without thrombolytic therapy was assumed to be greater than 3 percent, if the rate of fatal or incapacitating complications due to thrombolytic therapy was assumed to be 4 percent or less, or if the relative reduction in the risk of death associated with thrombolytic therapy was assumed to be greater than 1 percent. On the basis of our base-line assumptions, our estimate of the cost effectiveness of streptokinase therapy (the cost per year of life saved) for an 80-year-old patient with suspected acute myocardial infarction was $21,200. For a wide range of assumptions about risks, benefits, and costs, the cost per year of life saved remained less than $55,000. CONCLUSIONS. Within the limitations imposed by the assumptions used in our analysis, thrombolytic therapy with streptokinase was found to be a beneficial and cost-effective treatment for suspected acute myocardial infarction in elderly patients in a wide variety of clinical circumstances.     

Angioscopic evaluation of coronary-artery thrombi in acute coronary syndromes.

BACKGROUND. Disruption of an atherosclerotic plaque in a coronary artery followed by the formation of a thrombus is believed to be the cause of both unstable angina and acute myocardial infarction. Although thrombolytic therapy is efficacious in patients with acute myocardial infarction, for unknown reasons it is far less effective in patients with unstable angina. We postulated that there might be differences in the composition of the coronary-artery thrombi in unstable angina and acute myocardial infarction. METHODS. To investigate the appearance of coronary-artery thrombi, we performed percutaneous transluminal coronary angioscopy in 15 patients with unstable angina and 16 with acute myocardial infarction. Angioscopy was performed within 48 hours after an episode of pain at rest in the patients with unstable angina and within 8 hours of onset in those with acute myocardial infarction. RESULTS. Angioscopy revealed coronary thrombi in all but two patients (one in each group). Of the 29 patients with thrombi, those with unstable angina were frequently observed to have grayish-white thrombi (10 of 14, 71 percent), but none were seen in the 15 patients with acute myocardial infarction (P less than 0.01). By contrast, reddish thrombi were observed in all 15 patients with acute myocardial infarction who had thrombi, but in only 4 of the 14 patients with unstable angina and thrombi (P less than 0.01). As assessed by coronary angiography, occlusive thrombi occurred frequently in patients with acute myocardial infarction (13 of 16 patients) but were not seen in any of the 15 patients with unstable angina (P less than 0.01). CONCLUSIONS. Coronary-artery thrombi play an important part in the pathogenesis of unstable angina and acute myocardial infarction. However, the appearance of the thrombi is different in the two conditions, possibly reflecting differences in the composition of age of the thrombi or the presence or absence of blood flow in the artery. This difference may account for the contrasting results of thrombolytic therapy.     

Asymmetric dimethylarginine (ADMA) levels display a morning peak in patients with acute myocardial infarction

High Asymmetric Dimethylarginine (ADMA) levels are associated with increased platelet activity, elevated blood pressure, vasoconstriction and impaired vascular relaxation. We hypothesized that the myocardial infarction morning peak of occurrence is closely related to a morning peak of ADMA levels. We performed a cross-sectional study among patients with documented myocardial infarction who had been enrolled in the prospective MISSION! Intervention Study. In total, serum ADMA levels were measured in their acute setting of myocardial infarction in 120 patients. The frequency of myocardial infarction onset of symptoms and emergency coronary catheterization and the ADMA levels displayed a similar daily pattern with a morning peak between 06:00-11:59 h. The absolute ADMA levels peak was between 06:00-07:59 h with a median (interquartile range) peak value of 1.01 (0.84-1.21) μmol/L for the n=9 patients vs. 0.75 (0.61-0.89) μmol/L for the remaining 111 patients admitted throughout the rest of the 24-hour interval (p=0.003 for between groups comparison). The amplitude (95% 0.08 μmol/L (0.004-0.16) with p=0.042 for statistic model significance. In conclusion, ADMA levels display a 24-hour variation with a significant morning peak in patients with acute myocardial infarction. These findings may relate ADMA levels to the acute onset of thrombotic cardiovascular events.     

Missed diagnoses of acute cardiac ischemia in the emergency department

BACKGROUND: Discharging patients with acute myocardial infarction or unstable angina from the emergency department because of missed diagnoses can have dire consequences. We studied the incidence of, factors related to, and clinical outcomes of failure to hospitalize patients with acute cardiac ischemia. METHODS: We analyzed clinical data from a multicenter, prospective clinical trial of all patients with chest pain or other symptoms suggesting acute cardiac ischemia who presented to the emergency departments of 10 U.S. hospitals. RESULTS: Of 10,689 patients, 17 percent ultimately met the criteria for acute cardiac ischemia (8 percent had acute myocardial infarction and 9 percent had unstable angina), 6 percent had stable angina, 21 percent had other cardiac problems, and 55 percent had noncardiac problems. Among the 889 patients with acute myocardial infarction, 19 (2.1 percent) were mistakenly discharged from the emergency department (95 percent confidence interval, 1.1 to 3.1 percent); among the 966 patients with unstable angina, 22 (2.3 percent) were mistakenly discharged (95 percent confidence interval, 1.3 to 3.2 percent). Multivariable analysis showed that patients who presented to the emergency department with acute cardiac ischemia were more likely not to be hospitalized if they were women less than 55 years old (odds ratio for discharge, 6.7; 95 percent confidence interval, 1.4 to 32.5), were nonwhite (odds ratio, 2.2; 1.1 to 4.3), reported shortness of breath as their chief symptom (odds ratio, 2.7; 1.1 to 6.5), or had a normal or nondiagnostic electrocardiogram (odds ratio, 3.3; 1.7 to 6.3). Patients with acute infarction were more likely not to be hospitalized if they were nonwhite (odds ratio for discharge, 4.5; 95 percent confidence interval, 1.8 to 11.8) or had a normal or nondiagnostic electrocardiogram (odds ratio, 7.7; 95 percent confidence interval, 2.9 to 20.2). For the patients with acute infarction, the risk-adjusted mortality ratio for those who were not hospitalized, as compared with those who were, was 1.9 (95 percent confidence interval, 0.7 to 5.2), and for the patients with unstable angina, it was 1.7 (95 percent confidence interval, 0.2 to 17.0). CONCLUSIONS: The percentage of patients who present to the emergency department with acute myocardial infarction or unstable angina who are not hospitalized is low, but the discharge of such patients is associated with increased mortality. Failure to hospitalize is related to race, sex, and the absence of typical features of cardiac ischemia. Continued efforts to reduce the number of missed diagnoses are warranted.     

The management of suspected myocardial infarction by Scottish general practitioners with access to community hospital beds.

General practitioners working in 20 community hospitals in Scotland participated in a survey of the management of myocardial infarction. During one year they suspected acute myocardial infarction in 451 patients. Of these patients, 278 (62%) were admitted to a community hospital, 125 (28%) to a district general hospital and 48 (11%) were kept at home. The main reasons given for admission to a community hospital were for monitoring and investigation, while the main reasons for admission to a district hospital rather than a community hospital were the relative youth of the patient and the severity of the illness. Acute myocardial infarction was confirmed in 323 (72%) cases, but in 26 (6%) cases the final diagnosis was other than ischaemic heart disease. Patients with acute myocardial infarction who entered a community hospital did so a median of two hours 25 minutes after the onset of symptoms. Among 18 patients admitted to a community hospital in whom resuscitation was attempted after cardiac arrest four (22%) were subsequently discharged from hospital. The mortality rate from acute myocardial infarction in the community studied was 171/418 (41%), of whom 95 died suddenly before coming under medical care. It is concluded that in rural areas of Scotland an acceptable standard of care for patients with acute myocardial infarction, including the administration of thrombolytic therapy, could be provided rapidly by general practitioners working in community hospitals.     

The detection of myoglobin in urine and its application to the diagnosis of myocardial infarction.

An indirect haemaglutination method was developed for the immunochemical detection of myoglobin in human urine. Myoglobin was found in the urine of 84% of 44 patients with acute myocardial infarction. In contrast, it was detected in the urine of 2.7% of 147 control subjects and in none of a control group of 15 patients who had received intramuscular injections. In patients with myocardial infarction, myoglobin was detected in most but not all urine specimens collected between 10 and 50 hours after the onset of chest pain. The results suggest that the detection of myoglobin in urine may be a valuable addition to present tests for the diagnosis of acute myocardial infarction.     

The effect of warfarin on mortality and reinfarction after myocardial infarction

BACKGROUND AND METHODS. The use of oral anticoagulation in the long-term treatment of survivors of acute myocardial infarction has been highly controversial. We therefore randomly assigned 1214 patients who had recovered from acute myocardial infarction (mean interval from the onset of symptoms to randomization, 27 days) to treatment with warfarin (607 patients) or placebo (607 patients) for an average of 37 months (range, 24 to 63). RESULTS. At the end of the treatment period, there had been 123 deaths in the placebo group and 94 in the warfarin group--a reduction in risk of 24 percent (95 percent confidence interval, 4 to 44 percent; P = 0.027). A total of 124 patients in the placebo group had reinfarctions, as compared with 82 in the warfarin group--a reduction of 34 percent (95 percent confidence interval, 19 to 54 percent; P = 0.0007). Furthermore, we observed a reduction of 55 percent (95 percent confidence interval, 30 to 77 percent) in the number of total cerebrovascular accidents in the warfarin group as compared with the placebo group (44 vs. 20; P = 0.0015). Serious bleeding was noted in 0.6 percent of the warfarin-treated patients per year. CONCLUSIONS. Long-term therapy with warfarin has an important beneficial effect after myocardial infarction and can be recommended in the treatment of patients who survive the acute phase.     

Effect of intravenous streptokinase as compared with that of tissue plasminogen activator on left ventricular function after first myocardial infarction

In a double-blind trial comparing two thrombolytic agents as treatment for acute myocardial infarction, we randomized 270 consecutive patients an average (+/- SD) of 2.5 +/- 0.6 hours after the onset of chest pain from a first myocardial infarction--135 to receive intravenous streptokinase (1.5 million units over 30 minutes) and 135 to receive intravenous recombinant tissue plasminogen activator (rt-PA) (100 mg over three hours). The primary end point was left ventricular function as assessed by cineangiography performed three weeks after infarction. The effects of the two agents on left ventricular function were similar. The ejection fraction was identical (58 +/- 12 percent) in both groups. The end-systolic volume was 61 +/- 29 ml in the streptokinase group and 66 +/- 31 ml in the rt-PA group (P not significant). Patency rates at three weeks for the infarct-related artery were also similar (75 percent in the streptokinase group and 76 percent in the rt-PA group). Reinfarction rates at 30 days were the same (5 percent) in both groups. One patient had a fatal intracerebral hemorrhage 13 hours after receiving rt-PA, and another had a fatal cerebellar hemorrhage 21 hours after receiving rt-PA for reinfarction nine days after treatment with streptokinase. An intention-to-treat analysis revealed that mortality at 30 days was 3.7 percent in the rt-PA group as compared with 7.4 percent in the streptokinase group (P greater than 0.2). Follow-up for a mean of 9.0 months revealed no significant difference in survival; we observed 12 deaths (8.9 percent) in the streptokinase group and 8 deaths (5.9 percent) in the rt-PA group (P = 0.34). We conclude that rt-PA and streptokinase, in the doses given, have similar effects on left ventricular function after a first myocardial infarction. Because of the small number of deaths, it is not possible to determine whether their effects on mortality are similar.     

Temporal trends in cardiogenic shock complicating acute myocardial infarction

BACKGROUND: Limited information is available on trends in the incidence of and mortality due to cardiogenic shock complicating acute myocardial infarction. We studied the incidence of cardiogenic shock complicating acute myocardial infarction and in-hospital death rates among patients with this condition in a single community from 1975 through 1997. METHODS: We conducted an observational study of 9076 residents of metropolitan Worcester, Massachusetts, who were hospitalized with confirmed acute myocardial infarction in all local hospitals during 11 one-year periods between 1975 and 1997. Our study included periods before and after the advent of reperfusion therapy. RESULTS: The incidence of cardiogenic shock remained relatively stable over time, averaging 7.1 percent among patients with acute myocardial infarction. The results of a multivariable regression analysis indicated that the patients hospitalized during recent study years were not at a substantially lower risk for shock than patients hospitalized in the mid-to-late 1970s. Patients in whom cardiogenic shock developed had a significantly greater risk of dying during hospitalization (71.7 percent) than those who did not have cardiogenic shock (12.0 percent, P<0.001). A significant trend toward an increase in in-hospital survival among patients with cardiogenic shock in the mid-to-late 1990s was found in crude and adjusted analyses. CONCLUSIONS: Our findings indicate no significant change in the incidence of cardiogenic shock complicating acute myocardial infarction over a 23-year period. However, the short-term survival rate has increased in recent years at the same time as the use of coronary reperfusion strategies has increased.     

Aspirin, heparin, or both to treat acute unstable angina

We tested the usefulness of aspirin (325 mg twice daily), heparin (1000 units per hour by intravenous infusion), and a combination of the two in the early management of acute unstable angina pectoris in a double-blind, randomized, placebo-controlled trial involving 479 patients. The patients entered the study as soon as possible after hospital admission (at a mean [+/- SD] of 7.9 +/- 8.0 hours after the last episode of pain), and the study was ended after 6 +/- 3 days, when definitive therapy had been selected. Major end points--refractory angina, myocardial infarction, and death--occurred in 23, 12, and 1.7 percent of the 118 patients receiving placebo, respectively. Heparin was associated with a decrease in the occurrence of refractory angina (P = 0.002). The incidence of myocardial infarction was significantly reduced in the groups receiving aspirin (3 percent; P = 0.01), heparin (0.8 percent; P less than 0.001), and aspirin plus heparin (1.6 percent, P = 0.003), and no deaths occurred in these groups. There were too few deaths overall to permit evaluation of the effect of treatment on this end point. The combination of aspirin and heparin had no greater protective effect than heparin alone but was associated with slightly more serious bleeding (3.3 vs. 1.7 percent). We conclude that in the acute phase of unstable angina, either aspirin or heparin treatment is associated with a reduced incidence of myocardial infarction, and there is a trend favoring heparin over aspirin. Heparin treatment is also associated with a reduced incidence of refractory angina.     

Assessment of the value of pelvic ultrasonography in pre-menopausal women with right iliac fossa pain

The aim of this study was to determine whether ultrasound examination performed in the acute setting can avoid the need for diagnostic laparoscopy in pre-menopausal women presenting with right iliac fossa pain in whom the diagnosis of acute appendicitis is suspected. All female patients aged fifty or under, who presented to the Emergency Department with right iliac fossa pain over an eighteen-month period, and who went on to have a diagnostic laparoscopy performed, were included in the study. Ultrasound and operative findings were recorded. 147 patients fulfilling the study criteria were identified. 38 (26%) had pre-operative ultrasound performed. 15 of these had normal findings, 10 had gynaecological pathology identified, 8 had non-specific findings. Of the 38 patients who had pelvic ultrasound pre-operatively, 26 (68%) had acute appendicitis at laparoscopy, only 5 of whom had a sonographic diagnosis of acute appendicitis made pre-operatively. We conclude that while positive ultrasound findings in cases of acute appendicitis are helpful, negative studies do not exclude the diagnosis. Patients in whom there is a strong clinical suspicion of acute appendicitis should proceed directly to laparoscopy while patients in whom the diagnosis is less certain, should be admitted for a period of observation facilitating repeated clinical evaluation. In this subgroup of patients, further imaging studies such as computed tomography may be indicated.