Prediction rules for patients with suspected myocardial infarction. Applying guidelines in community hospitals

Several clinical prediction rules have been developed to assist physicians in managing intensive care resources for patients with suspected myocardial infarction. These guidelines, developed in university settings, attempt to identify patients at high or low risk for developing life-threatening complications or death. Since some prediction rules have not performed well when applied to different patient populations, we applied these rules to 397 patients with suspected myocardial infarction who were admitted to community hospital coronary care units. The relative risk of dying associated with an abnormal initial electrocardiogram declined from 17 in the academic center to 2.9 in the community hospital. In contrast, a guideline that uses data available after 24 hours of observation did segregate patients at higher and lower risk in both the community and academic hospitals. This study shows that clinical prediction rules that were developed in academic medical centers should be validated before applying them in community hospital settings.     

老年人急性心肌梗死近期转归分析

目的探讨老年急性心肌梗死（ＡＭＩ）患者近期转归的影响因素，为降低病死率提供理论依据。方法连续住院的３０５例首次ＡＭＩ老年患者，男１４６例，女１５９例，对比分析其临床基础情况、梗死表现、治疗及临床经过、住院病死率及死亡原因，并对影响转归的变量进行多元回归分析。结果老年女性并存高血压和糖尿病的百分率较男性高（分别为５６％对２９％，３３％对１８％），男性吸烟者较女性多（４０％对２％），差异均有显著性（均为Ｐ＜０．０１）。老年女性的心力衰竭、休克、机械并发症和住院病死率均高于男性（均为Ｐ＜０．０５）。然而，多元回归分析显示，性别并不是住院死亡的独立危险因子（ＯＲ，０．７３；９５％ＣＩ，０．２５～２．２３），而心功能Ｋｉｌｉｐ分级（ＯＲ，６．８２；９５％ＣＩ，２．５０～１８．９１）、机械并发症（ＯＲ，５３．１８；９５％ＣＩ，１１．５６～４０１．３０）、肌酸激酶（ＣＰＫ）峰值（ＯＲ，１．６９；９５％ＣＩ，１．１８～２．４７）等可能有重要预后价值。结论老年ＡＭＩ患者死亡危险性增加与心脏本身的危险因子有关，而性别无重要影响。     

Prediction of death and myocardial infarction by radionuclide angiocardiography in patients with suspected coronary artery disease

The prognostic value of radionuclide angiocardiography was examined in patients with suspected coronary artery disease. Nine hundred and eight patients who underwent rest and exercise radionuclide angiocardiography without subsequent cardiac catheterization were followed for a median of 4.6 years. Fifty-two cardiovascular deaths and 28 nonfatal myocardial infarctions occurred during the follow-up period. Thirty-nine radionuclide angiocardiographic and clinical variables were analyzed in association with the end points of cardiovascular death, total cardiac events and death from all causes using the Cox proportional hazards model and Kaplan-Meier survival estimates. Univariable analysis identified the exercise ejection fraction as the best predictor of cardiovascular death (chi-square = 82), total cardiac events (chi-square = 84) and death from all causes (chi-square = 66). A small subset of patients (n = 45) with an exercise ejection fraction less than 0.35 were at high risk for future cardiac events, whereas most patients (n = 776) had an exercise ejection fraction greater than or equal to 0.50 and a low probability of a subsequent event. Three variables--the exercise ejection fraction, the exercise change in heart rate, and gender--contained independent prognostic information determined by multivariable analysis. The exercise ejection fraction was the strongest independent predictor (p less than 0.0001) for every end point. The measurement of ventricular function during exercise provides important independent prognostic information in patients with suspected coronary artery disease. Radionuclide angiocardiography successfully identifies patients requiring invasive assessment, and the low probability of cardiac events in patients with good exercise ventricular function obviates the need for interventional therapy.     

肾小球滤过率对老年急性心肌梗死近期预后的影响

目的探讨入院时估测肾小球滤过率(eGFR)对老年急性心肌梗死(AMI)住院患者近期(30d内)预后的影响。方法入选2001年1月至2007年12月因AMI收住的327例老年患者为研究对象。根据入院时eGFR水平ml/(min·1.73m2)分为4组:肾功能正常组(eGFR≥80),轻度肾功能不全组(eGFR60～79),中度肾功能不全组(eGFR30～59)及重度肾功能不全组(eGFR30)。统计分析30d心源性病死和心脏并发症(心源性休克、心力衰竭或室速/室颤)的发生率及影响近期预后的相关因素。结果 4组患者30d病死率分别为3.7%、12.1%、23.6%和28.6%,心脏并发症的发生率分别为15.4%、37.4%、59.7%和64.3%(均P0.01)。单因素分析显示,年龄,糖尿病、脑卒中病史,贫血,首发症状呼吸困难,并发心源性休克、心力衰竭或室速/室颤及入院时eGFR减低是30d病死率的危险因素(均P0.05)。多因素分析显示,入院时eGFR减低、年龄、伴糖尿病者30d病死率均增高,比值比(OR)分别为1.6095%可信区间(CI)1.08～2.36、1.07(95%CI1.02～1.13)和3.34(95%CI1.34～8.34);住院期间发生心源性休克、心力衰竭及室速/室颤者同样也增加30d病死率,OR分别为16.18(95%CI4.68～55.97)、5.33(95%CI2.26～12.56)和3.99(95%CI1.29～12.33)。结论老年AMI患者入院时eGFR降低是急性期预后的独立预测因子。     

不同入院心率水平与ST段抬高型心肌梗死患者预后的关系

目的 探讨入院时心率水平与ST段抬高型心肌梗死(STEMI)患者近期病死率的相关性.方法分析国际大规模临床试验CREATE研究数据库中7485例中国STEMI患者,以入院不同心率水平分为＜ 60次/min组(991例)、60～69次/min组(1491例)、70～79次/min组(1743例)、80～89次/min组(1495例)、90～99次/min组(794例)和≥100次/min组(971例),分析各组患者30 d的心血管终点事件发生情况.结果基线资料显示,心率≥90次/min的2组患者中,入院血糖水平,女性、前壁梗死、既往高血压、糖尿病、心功能killipⅡ～Ⅳ级发生率均高于60～69次/min组(P＜0.05).心率＜ 60次/min组病死率高于60～69次/min组(9.6％比6.3％,P＜0.05),心率≥60次/min的所有患者中,随心率水平升高,各组间病死率呈增加趋势(依次为6.3％、8.1％、9.2％、12.6％和24.6％,P＜0.05);30 d联合终点事件发生率呈现先降低后升高的变化[心率＜60次/min 组27.0％、60～69次/min组12.5％、70～9次/min组13.7％、80～89次/min组14.3％、90～99次/min组17.5％、≥100次/min组31.1％(P＜0.001)].多因素回归分析结果显示,与心率60～69次/min组相比,＜60次/min组患者30 d病死率差异无统计学意义(p＞0.05),其余各组随心率水平升高30 d死亡风险逐步增加(心率70～79次/min组:OR=1.391,95％ CI 1.028～1.883,P＜0.05;80～89次/min组:OR=1.447,95％ CI 1.066～1.966,P＜0.05;90～99次/min组:OR=1.834,95％ CI1.303～2.582,P＜0.05;≥100次/min组:OR=2.579,95％ CI 1.893～3.515,P＜0.001);与心率60～69次/min组比较,心率＜60次/min和＞90次/min患者联合终点事件风险明显增加(OR值分别为1.532,1.436,1.893,P均＜0.05).结论STEMI患者入院心率是近期预后的危险因素.     

Rapid serial enzyme measurements in evaluation of patients with suspected myocardial infarction

Because clinical and laboratory criteria cannot accurately establish the presence or absence of acute myocardial infarction (AMI) at the time of initial presentation, this diagnosis is not confirmed in the majority of patients admitted to coronary care units. To study the effectiveness of serial changes in enzyme activity in specimens taken at presentation and 8 hours later in establishing the likelihood of AMI, the results in 1,214 patients with acute cardiac symptoms of less than 24 hours' duration were retrospectively evaluated. In 1,007 patients with initially normal creatine kinase (CK), an increase in CK (positive delta-CK) occurred in 98% of patients with AMI and 16% of patients without AMI. In 196 patients with elevated total CK, a low ratio of CK to aspartate aminotransferase was found in 98% of patients with AMI and 33% of patients without AMI. These 2 enzyme ratios had a sensitivity greater than 90% in patients with typical and atypical histories. The overall predictive value of serial enzyme measurements for AMI was 53%, compared with 18% in patients selected for admission. These results suggest that serial enzyme measurements could be used in the initial evaluation of patients with suspected AMI, and have the potential to reduce the number of patients admitted to coronary care units who do not have AMI.     

New biomarkers in the risk stratification of patients with suspected acute myocardial infarction

The acute coronary syndromes (ACS) remain a diagnostic and prognostic challenge for today’s physician. Over the past decade, studies have identified several serologic biomarkers to aid the clinician in assessing risk and predicting outcomes in ACS. Still others are being identified that show promise for increasing the accuracy with which this risk is assessed. However, further research remains necessary to identify the perfect cardiac biomarker or combination of markers and to define their roles in clinical management of ACS patients.     

Prediction of short-term outcome in newly admitted psychogeriatric patients.

Thirty-six consecutive admissions to a geriatric service recently reorganized to function within a community psychiatric framework were evaluated by means of a series of behavioral and psychologic measures. Assessments upon admission and at three, five and eight weeks and five months afterward, revealed that the greatest therapeutic responses and the most discharges occurred within the first few weeks after admission. Patients remaining for longer periods tended to stabilize at a lower level of functioning or to deteriorate. A combination of two simple measures used in evaluation upon admission and relating to physical and mental functioning was found to predict the patient's status at five months (still in the hospital, dead, or discharged) with 75 percent accuracy. Use of the lambda statistic for judging the predictive power of measures is suggested.     

Effect of labetalol on indices of myocardial necrosis in patients with suspected acute infarction

The role of combined alpha and beta blockade as a means of limitinginfarct size has been studied in a randomised controlled trialusing labetalol. Only 166 of 630 (26%) consecutive patientsadmitted to a cardiac care unit with suspected myocardial infarctionwere deemed suitable for inclusion; most of the remainder haddelayed admission to hospital, were over the age limit of 75,or had complications which precluded the use of labetalol. Thoseon active treatment received a loading dose followed by a slowintravenous infusion over six hours, and oral therapy for thesubsequent five days. Doses were adjusted to maintain systolicpressure in the range 100 to 120 mmHg. The control group receivedonly conventional therapy. Labetalol caused lowering of theblood pressure and heart rate during the phase of intravenoustreatment, but little effect occurred subsequently because oraldosage was constrained by low systolic pressures. The groupthat received active treatment had significantly greater releaseof CKMB enzyme. Little difference was observed in R wave scoresor ejection fraction. Only low doses of labetalol can be usedfor most patients with acute myocardial infarction. Labetalolcannot be recommended as routine treatment for normotensivepatients admitted to hospital with suspected infarction.     

Prediction of arrhythmic events in patients following myocardial infarction

The value of techniques used to predict arrhythmic events (sudden cardiac death not preceded by reinfarction and spontaneous sustained ventricular tachycardia) after acute myocardial infarction is reviewed. A full clinical assessment allows the detection of patients with major infarction, present in the majority of those suffering arrhythmic events during follow-up. More sophisticated noninvasive tests, including Holter monitoring, and the high gain, signal averaged ECG, add prognostic accuracy to clinical assessment in patients with major infarction but are by themselves nonspecific. Noninvasive assessment of autonomic function from baroreceptor sensitivity analysis and heart rate variability measurement may also provide useful prognostic information. The results of programmed ventricular stimulation studies in patients with recent acute infarction have been contradictory, though many of the disagreements can be explained by methodological differences. At best this technique is highly invasive, and probably adds little to what can be discovered from a thorough noninvasive assessment. The treatment to be adopted in those judged to be at high risk remains to be established, and this may include nonpharmacological modalities such as the implantable defibrillator and surgical ablation as alternatives to drug therapy.     

Effect of mobile paramedic units on outcome in patients with myocardial infarction

To investigate the effect of mobile paramedic units on outcome, we prospectively studied for two years all patients with myocardial infarction admitted to the LDS Hospital emergency department who sought aid prior to cardiac arrest. One hundred thirty-four patients who received prehospital care from a mobile paramedic unit were compared with 101 patients who selected another means of initial care. Mortality, occurrence of life-threatening arrhythmias, and change in Killip class at 24 and 48 hours were the outcome variables. Data analysis by multiple logistic regression revealed that outcome was not improved, but a 29-minute median delay in hospital arrival occurred in paramedic-treated patients. Defibrillation was the only beneficial treatment performed by paramedics that could be identified. Current mobile paramedic unit procedures may need to be streamlined to eliminate the delay in hospital arrival resulting from extensive prehospital care.     

长程与短程心率变异性的结合对于急性心肌梗死患者预后的意义

目的 比较长程与短程心率变异性（ＨＲＶ）分析对于急性心肌梗死（ＡＭＩ）患者预后的不同预测价值。方法 选择１９９５年１０月至１９９６年１２月入我院的ＡＭＩ患者５０例,结合时域与频域的方法,分别进行长程（２４小时）,短程（１－３小时）分析。结果 长程短程ＨＲＶ分析相关性很强,相关系数在０．７４～０．９８之间。 长程分析还是短程分析ＨＲＶ,在６个月随访死亡病例中均降低,除高频（ＨＦ）低高频比值（ＬＦ／Ｈ     

Prophylactic lidocaine in suspected acute myocardial infarction

We gave 50 consecutive patients with suspected acute myocardial infarction prophylactically lidocaine 300 mg intramuscularly and 100 mg intravenously. Although therapeutic plasma levels were reached, 2 of 24 (8%) patients with acute myocardial infarction had ventricular tachycardia or ventricular fibrillation and 3 of 50 (6%) became hypotensive during the first hour of lidocaine.     

Clinical and angiographic outcome of patients with acute inferior myocardial infarction

OBJECTIVES: This study sought to determine the procedural success and the in-hospital outcome after primary coronary angioplasty in patients with acute inferior myocardial infarction and right ventricular involvement (RVI). BACKGROUND: RVI represents an easily detectable, highly prevalent subset of acute inferior infarction associated with poor outcome even in the era of thrombolysis. Primary PTCA may offer advantages in patients with inferior infarction involving the right ventricle. METHODS: Primary coronary angioplasty with optimal stenting was performed in 87 of 88 consecutive patients presenting within 24 hours after onset of acute inferior myocardial infarction. On the basis of right precordial ST segment elevations at admission, patients were classified into those without (n=61) and those with RVI (n=27). The patients were followed prospectively for angiographic success at 10 days and for in-hospital clinical outcome. RESULTS: Baseline characteristics including age, severity of coronary artery disease, proportion of stent implantation, and occurrence of cardiogenic shock were comparable. Patients with RVI had larger infarct sizes (lactate dehydrogenase level: 962 vs 580 U/l, P=0.03), developed more often complete atrioventricular block (18.5 vs. 2%, p=0.0038), needed more often parasympatholytics (48.1 vs 18.8%, p<0.001), and had a substantially higher incidence of the Bezold-Jarisch reflex (29.6 vs 6.6%, p<0.01) following reperfusion.Success of recanalization therapy acutely and at 10 days, as well as in hospital mortality were similar in patients with and without RVI (88.5 vs. 85.2%, 79.3 vs. 84.7%, 7.4 vs 9.8%). However, patients with RVI revealed a greater lumen gain acutely after PTCA (2.49 vs. 2.13 mm, p=0.025) and experienced less frequently major cardiac events (14.8 vs. 36.1%, p=0.04) which included reinfarction, re-ischemia, coronary bypass grafting, stent thrombosis, and cardiac death. In addition, procedural success was established more rapidly (fluoroscopy time: 10 vs 15 min., p=0.032) and with less contrast material (242 vs 295 ml, p=0.015) in patients with RVI. This is probably due to the more proximal location (84.6 vs 6.6%, p<0.0001) and the larger reference diameter (3.17 vs. 2.79 mm, p=0.03) of the occluded right coronary artery. CONCLUSIONS: Primary PTCA is an appropriate reperfusion strategy in patients with RVI. Further comparative studies are required to compare the effectiveness of primary PTCA with early thrombolytic therapy in this high risk setting.