Statement of the ad hoc committee on the laboratory diagnosis of infectious and serum hepatitis.

A prospective study was carried out to determine the prognostic factors in patients with second-degree and complete heart block following acute myocardial infarction and to re-examine the indications for artificial transvenous pacing. Of the 117 consecutive patients with proved acute myocardial infarction, 15 developed advanced heart block (second degree and complete). The presence of the following factors, either alone or in combinations, were attended with poor prognosis: preceding Stokes-Adams syndrome, cardiogenic shock, congestive heart failure, complications secondary to cardiac arrest, anterior infarction and wide QRS complex. In the nine cases requiring artificial transvenous pacemaker because of Stokes-Adams attacks, congestive heart failure or frequent multifocal ventricular ectopic beats, there were five deaths. The remaining six patients, who were without complications and were not paced, all survived; these patients had normal QRS duration with heart rates above 60 per minute. This study indicates that prophylactic transvenous catheter insertion in acute heart block does not appear justified unless specific indication(s) arise. Postmortem studies revealed significant narrowing of all the major coronary vessels in all five fatalities. The overall mortality in this series of cases of acute heart block was 33%.     

Effect of Digoxin on A-V Conduction

The effect of digoxin on A-V conduction in 19 patients with known disease of their conduction tissue was studied while a demand pacing system was in position. Fifteen had transient complete heart block after myocardial infarction and four had chronic intermittent complete heart block. The patients were studied on return to sinus rhythm.In no instance was a return to either second- or third-degree heart block precipitated in these patients despite therapeutic levels and, in some cases, high serum level of digoxin for a period of seven days.The duration of complete heart block after myocardial infarction was 4·3 days in those taking digoxin while in heart block and 3·3 days in those who started digoxin only after return to sinus rhythm.     

Immunoscintigraphy for detecting acute myocardial infarction without electrocardiographic changes.

OBJECTIVE--To establish whether immunoscintigraphy with antibody to myosin may detect acute myocardial infarction without electrocardiographic changes. DESIGN--Prospective study of patients with suspected acute myocardial infarction or unstable angina with cardiac imaging with 111indium myosin antibody, estimation of cardiac enzyme concentrations, electrocardiography, 201thallium imaging, and radionuclide ventriculography. SETTING--Coronary care unit in a district general hospital. PATIENTS--119 Consecutive patients with suspected acute myocardial infarction or unstable angina. Patients with cardiomyopathy, myocarditis, valvular heart disease, myocardial infarction or cardiac surgery in the previous two weeks or with left bundle branch block and women of childbearing age were excluded. RESULTS--Of 75 patients with suspected acute myocardial infarction, seven had no diagnostic electrocardiographic changes despite normal conduction patterns. Immunoscintigraphy with myosin antibody disclosed necrosis in all seven patients, which was localised in regions supplied by diseased coronary arteries in all but one. Six patients had abnormal images on 201thallium imaging, and all seven had abnormal wall motion at the site of antibody uptake. One patient with minimal left main stem and right coronary artery atheroma had uptake of antibody at two discrete sites. CONCLUSIONS--Immunoscintigraphy with antibody to myosin confirms myocardial infarction in the absence of electrocardiographic changes and discloses the site of infarction.     

The Implantable Cardiac Pacemaker

The transistorized implanted pacemaker is proving to be an effective and reliable method for long-term pacing of the heart. All patients suffering from Stokes-Adams seizures were first given a trial period of conservative therapy, including isoproterenol (Isuprel), ephedrine, atropine and steroids. Twenty-four pacemaker implants were performed on 23 patients over a 21-month period. The preoperative insertion of a pacemaker cardiac catheter was a very valuable safety precaution. In this way the heart could be safely and reliably paced during the period of preoperative assessment and during the critical periods of anesthetic induction and thoracotomy. Infection did not occur, probably because of careful gas sterilization of the units. Various models of pacemakers are compared, and the reasons for two pacemaker failures are presented. There were two early deaths and one late death in the series. The relationship of progressive coronary disease to recent infarction is stressed. Patients having intermittent heart block frequently showed the picture of “competing pacemakers” postoperatively, but without deleterious effect. Twenty patients, between 54 and 88 years of age, are alive and well at the time of reporting, with excellent pacemaker response and no further Stokes-Adams attacks.     

Artificial Cardiac Pacemakers

Nine patients with complete heart block and Stokes-Adams disease were treated with subcutaneously implanted, fixed-rate, artificial cardiac pacemakers. All of these patients were refractory to medical treatment and confined to bed by the frequency of their attacks. One patient died in uremia one month after operation; in the remaining eight, the implanted pacemakers are providing adequate stimulation at present. These patients are free of seizures and show an improvement in the amount of their physical activity. A fixed rate of 60 to 65 per minute was adequate in all cases. The results of our clinical experience with cardiac pacemakers is satisfactory, but the possibility of mechanical failure limits their use to situations in which the patient is incapacitated despite medical treatment.     

Bundle-branch Block in Acute Myocardial Infarction

Bundle-branch block was present in 41 out of 415 patients admitted to a coronary care unit with acute myocardial infarction and was associated with more severe clinical infarction and an overall mortality of 56%. It is probable that permanent bundle-branch block develops soon after infarction and that most of the patients with permanent block have had clinically severe infarction. Bundle-branch block developing during observation is usually transient, and the later it develops the sooner it resolves.Analysis of the arrhythmias and clinical course of the patients suggests that those with bundle-branch block and shock and those in whom bundle-branch block is present on admission may benefit from the use of a demand pacemaker attached to a transvenous pacemaker catheter, though the dividends of pacing may be small and the risks of the procedure significant. Post-mortem examination of 17 hearts showed extensive infarction, usually involving the septum, and severe coronary artery disease.     

The Artificial Cardiac Pacemaker—Indications for Implantation

Extensive clinical experience has demonstrated that implantable cardiac pacemakers are safe and effective mechanisms for controlling symptoms and preventing the hazards of third degree heart block with Stokes-Adams syncope. Medical management of this disease does not provide reliable protection and life expectancy averages about two years after diagnosis. Hence the negligible surgical morbidity and mortality associated with pacemaker implantation justifies broad indications to implant one of the four commercially available battery-powered units.Elective implantation of a pacemaker should be considered in patients with persistent third degree heart block who have had: One or more episodes of Stokes-Adams syncope; surgical injury to the conduction system, regardless of syncopal attacks; evidence of low cardiac output with cardiomegaly secondary to bradycardia. Few if any other cardiac arrythmias are satisfactorily controlled by an electrical pacemaker.Emergency pacemaker control is obviously necessary for patients developing intractable or recurrent bouts of asystole. During the interval until an implantable unit can be obtained and sterilized, the patient may be controlled by intravenous isoproterenol or by an external pacemaker attached to a transvenous catheter electrode, a precordial skin electrode or a percutaneous myocardial wire electrode.     

Advanced Heart Block During Acute Myocardial Infarction Treated with an Electrode Pacing Catheter

The mortality rate is high from advanced atrioventricular block associated with acute myocardial infarction. There is reason to believe that if in these patients the hearts are electrically paced with an endocardial pacing catheter, the mortality rate can be considerably decreased. Five patients in second- and third-degree heart block associated with acute myocardial infarction were paced with a considerable lowering of the expected mortality rate. Twenty-three cases from the literature are also presented and discussed. A silastic bipolar electrode catheter was used in these five cases. Four of the five cases returned to normal sinus rhythm within the first 10 days. The average duration of pacing was 6.7 days. It is the opinion of the author that second- and third-degree heart block associated with acute myocardial infarction should have a pacing catheter introduced at the earliest possible moment for continuous or demand endocardial pacing.     

Indications for Treatment of Complete Atrioventricular Dissociation

For purposes of correct treatment it is important to recognize that patients with complete atrioventricular dissociation fall into three groups: Group I—established third-degree heart block with and without Stokes-Adams attacks; Group II—periodic third-degree heart block with and without Stokes-Adams attacks; Group III—established third-degree heart block with cardiac failure. Most patients in Group I present no technical problems when a pacemaker is implanted. In Group II it is advisable to insert a temporary intracardiac catheter electrode and maintain a rate of 60 to 64 during the periods of third-degree heart block. Sudden reversion, in this group, from sinus rhythm can be fatal. Group III patients will often require a pacemaker set in excess of 74 beats until they are free of cardiac failure. Fifteen of 20 patients with complete atrioventricular dissociation showed marked functional improvement after insertion of a pacemaker. The development, in our laboratory, of a 4″ portable pacemaker impulse detector has been invaluable in locating the cause of failure in an implanted pacemaker.     

Emergency aorto-coronary venous bypass graft in cardiogenic shock

The mortality rate of shock complicating myocardial infarction is extremely high (80-100%) despite intensive medical management. Five patients with acute myocardial infarction and cardiogenic shock received an emergency aorto-coronary bypass graft, from three hours to five days after the onset of infarction and three to nine hours after the onset of shock. Selective coronary angiography was performed in all cases prior to operation. Four of the five patients survived and were discharged from hospital. Two cases with A-V dissociation and complete heart block reverted to normal sinus rhythm after the operation. This limited experience indicates that emergency aortocoronary bypass graft surgery can reduce mortality significantly in properly selected cases of cardiogenic shock.     

Does glycoprotein IIB/IIIA resistance exist?

Platelet function testing is not embedded into routine clinical practice, because no optimal, easy, reproducible and multipathway platelet aggregation test can be accomplished in vitro. Only recently, the relationship between the level of platelet aggregation inhibition by platelet inhibitors and clinical outcome in acute myocardial infarction became more clear.1-5 High platelet reactivity was found in patients who experienced stent thrombosis, and patients with clopidogrel resistance were at increased risk of recurrent atherothrombotic events.1,2 Furthermore, in ST-elevation myocardial infarction (STEMI) increased levels of platelet aggregation were found compared with unstable angina or control patients.4 In a thrombolysis study, higher platelet receptor occupancy was coupled with better angiographic and electrocardiographic outcome.     

Hyponatraemia and severity and outcome of myocardial infarction.

A total of 235 consecutive patients admitted to a coronary care unit were investigated for serum electrolyte and urea concentrations; activities of aspartate amino-transferase, lactate dehydrogenase, and lactate dehydrogenase isoenzymes; electrocardiographic changes; clinical state; and outcome. Hyponatraemia, hypochloraemia, and uraemia were common in patients with confirmed myocardial infarctions, the degree of infarction correlating well with all the above indices of severity. The day-to-day variability of plasma sodium, chloride, and potassium concentrations was often increased above normal. Disturbances were greater in patients given diuretics. It is concluded that plasma sodium concentration fall after infarction and that the extent and duration of the fall are indices of the severity of the infarction.     

Intravenous diazoxide in treatment of hypertension associated with recent myocardial infarction

Twenty patients with blood pressure over 180/110 mm Hg one hour after admission to a coronary care unit with recent acute myocardial infarction were given intravenous diazoxide in a bolus of 300 mg. The average blood pressure before diazoxide was 194/122 mm Hg. Blood pressure fell considerably in all patients, though six patients required two injections. The average fall was 58 mm Hg systolic and 40 mm Hg diastolic. No patient became severely hypotensive. The heart rate increased by an average of 10 beats/min. In nine patients the electrocardiographic changes immediately after the administration of diazoxide suggested an increase in myocardial injury. Though none of the patients seemed to deteriorate clinically from the diazoxide the electrocardiographic changes suggested that the use of intravenous diazoxide to lower blood pressure in patients with acute myocardial infarction might possibly be deleterious.     

急性下壁心肌梗死急诊PCI术中应用临时起搏器与阿托品的对比研究

目的：探讨临时起搏器与阿托品在急性下壁心肌梗死急诊经皮冠状动脉介入治疗（PCI）中应用的疗效。方法：入选2012 年2 月至2013 年8 月我院收治的发病12 小时内,诊断为急性下壁心肌梗死并接受急诊PCI治疗的患者92 例,依据治疗方法的不同 将病例分为临时起搏组和阿托品组,并对病例进行为期一年的追踪随访,收集患者平均住院天数、平均住院费用、再灌注心律失 常、心肌梗死后心绞痛、心肌梗死后心衰发生率资料。结果：临时起搏组的平均住院天数、平均住院费用、心肌梗死后心绞痛、心肌 梗死后心衰发生率均显著低于阿托品治疗组（P 均<0.05）,阿托品治疗组的再灌注心律失常发生率则明显低于临时起搏组（P<0. 05）。结论：急性下壁心肌梗死急诊PCI中应用临时起搏器,具有治疗成本低,降低心血管事件发生率的优点,而阿托品治疗在改 善再灌注心律失常的疗效上则显著优于临时起搏治疗。     

Effect of "fast track" admission for acute myocardial infarction on delay to thrombolysis.

OBJECTIVE--To evaluate the impact of a fast track triage system for patients with acute myocardial infarction. DESIGN--Comparison of delays in admission to hospital and in receiving thrombolytic treatment before and after introducing fast track system with delays recorded in 1987-8. Patients fulfilling clinical and electrocardiographic criteria for myocardial infarction were selected for rapid access to the cardiac care team, bypassing evaluation by the medical registrar. SETTING--Major accident and emergency, cardiac and trauma centre. SUBJECTS--359 patients admitted to the cardiac care unit during 1 February to 31 July 1990 with suspected acute infarction. MAIN OUTCOME MEASURES--Accuracy of diagnosis and delay from arrival at hospital to thrombolytic treatment. RESULTS--248 of the 359 patients had myocardial infarction confirmed, of whom 127 received thrombolytic treatment. The fast track system correctly identified 79 out of 127 (62%) patients who subsequently required thrombolytic treatment. 95% (79/83) of patients treated with thrombolysis after fast track admission had the diagnosis confirmed by electrocardiography and enzyme analysis. The median delay from hospital admission to thrombolytic treatment fell from 93 minutes in 1987-8 to 49 minutes in fast track patients (p less than 0.001). Delay in admission to the cardiac care unit was reduced by 47% for fast tract patients (median 60 minutes in 1987-8 v 32 minutes in 1990, p less than 0.001) and by 25% for all patients (60 minutes v 45 minutes, p less than 0.001). CONCLUSION--This fast track system requires no additional staff or equipment, and it halves inhospital delay to thrombolytic treatment without affecting the accuracy of diagnosis among patients requiring thrombolysis.     

Cardiac conduction abnormalities and Stokes-Adams attacks in myotonic dystrophy.

Myotonic dystrophy is a well known cause of cardiomyopathy. While various cardiac conduction abnormalities have been described in patients with myotonic dystrophy, so far only sporadic cases of Stokes-Adams attacks have been reported. Of 27 patients with this disease various conduction disturbances were detected in 17 (63%), 5 of whom presented with Stokes-Adams attacks and were found to have intracardiac conduction defects. The prognosis in four of the five patients was greatly improved with permanent pacemaker implantation.     

Indications for admission to a coronary care unit in patients with unstable angina.

One hundred cases with an admission diagnosis of acute coronary insufficiency or unstable angina were reviewed to establish criteria for admission to a coronary care unit. Myocardial infarction was subsequently diagnosed in 20 of the patients. Ventricular tachycardia occurred in 16 patients and ventricular fibrillation in 1 patient. Clinical features found to predict an increased risk of myocardial infarction included chest pain for more than 30 minutes within 24 hours prior to admission, new nonspecific electrocardiographic abnormalities consistent with ischemia, and diaphoresis. All patients with ventricular tachydysrhythmias had presented with both prolonged chest pain prior to admission and new electrocardiographic changes. The sensitivity, specificity and predictive value of various clinical criteria for identifying patients likely to have a myocardial infarction were calculated, and criteria with very high (greater than 90%) sensitivity were identified. These could be used to establish which patients are at increased risk of myocardial infarction and therefore require admission to a coronary care unit.     

临时起搏器经皮冠状动脉介入术治疗高风险冠状动脉病变的效果观察

目的分析并总结采用临时起搏器在实施经皮冠状动脉介入术治疗高风险冠状动脉病变中的应用效果。方法回顾性分析在临时起搏器支持下实施PCI的18例高危病人的临床资料,分析临时起搏器置入以及冠脉介入的操作情况。结果本组病人置入临时起搏电极起搏成功率达到100％。结论联合应用临时起搏器与经皮冠脉介入术治疗急性心肌梗死（AMI）与慢性血管闭塞性病变患者,能够降低经皮冠脉介入术治疗中由于严重心律失常导致的血液动力学改变,使病人尽快恢复正常心率以及各主要脏器的供血,减少患者的病死率,具有较高的安全性,值得在临床上广泛推广应用。     

Decreases in Electrocardiographic R-Wave Amplitude and QT Interval Predict Myocardial Ischemic Infarction in Rhesus Monkeys with Left Anterior Descending Artery Ligation

Clinical studies have demonstrated the predictive values of changes in electrocardiographic (ECG) parameters for the preexisting myocardial ischemic infarction. However, a simple and early predictor for the subsequent development of myocardial infarction during the ischemic phase is of significant value for the identification of ischemic patients at high risk. The present study was undertaken by using non-human primate model of myocardial ischemic infarction to fulfill this gap. Twenty male Rhesus monkeys at age of 2–3 years old were subjected to left anterior descending artery ligation. This ligation was performed at varying position along the artery so that it produced varying sizes of myocardial infarction at the late stage. The ECG recording was undertaken before the surgical procedure, at 2 h after the ligation, and 8 weeks after the surgery for each animal. The correlation of the changes in the ECG waves in the early or the late stage with the myocardial infarction size was analyzed. The R wave depression and the QT shortening in the early ischemic stage were found to have an inverse correlation with the myocardial infarction size. At the late stage, the R wave depression, the QT prolongation, the QRS score, and the ST segment elevation were all closely correlated with the developed infarction size. The poor R wave progression was identified at both the early ischemic and the late infarction stages. Therefore, the present study using non-human primate model of myocardial ischemic infarction identified the decreases in the R wave and the QT interval as early predictors of myocardial infarction. Validation of these parameters in clinical studies would greatly help identifying patients with myocardial ischemia at high risk for the subsequent development of myocardial infarction.     

Psychological rehabilitation after myocardial infarction.

The value of psychological counselling in rehabilitating patients after myocardial infarction was assessed. A total of 143 men who had recently had a myocardial infarction were randomly allocated to either a group receiving intensive rehabilitation or a control group, their outcome being examined after six months. Patients with neurotic, introverted personalities had a poor outcome in the control group but a satisfactory outcome when rehabilitated. Neurotic personalities responded to help, and rehabilitative measures did not increase neurosis. In addition all patients with a negative attitude towards their illness and future had a poor outcome but those with a positive attitude did well. Selection by simple methods of patients who would benefit from psychological rehabilitation seems desirable.