A national scheme for public access defibrillation in England and Wales: early results.

BACKGROUND: Automated external defibrillators (AEDs) operated by lay persons are used in the UK in a National Defibrillator Programme promoting public access defibrillation (PAD). METHODS: Two strategies are used: (1) Static AEDs installed permanently in busy public places operated by those working nearby. (2) Mobile AEDs operated by community first responders (CFRs) who travel to the casualty. RESULTS: One thousand five hundred and thirty resuscitation attempts. With static AEDs, return of spontaneous circulation (ROSC) was achieved in 170/437 (39%) patients, hospital discharge in 113/437 (26%). With mobile AEDs, ROSC was achieved in 110/1093 (10%), hospital discharge in 32 (2.9%) (P<0.001 for both variables). More shocks were administered with static AEDS 347/437 (79%) than mobile AEDs 388/1093 (35.5%) P<0.001. Highly significant advantages existed for witnessed arrests, administration of shocks, bystander CPR before arrival of AED and short delays to start CPR and attach AED. These factors were more common with static AEDs. For CFRs, patients at home did less well than those at other locations for ROSC (P<0.001) and survival (P=.006). Patients at home were older, more arrests were unwitnessed, fewer shocks were given, delays to start CPR and attach electrodes were longer. CONCLUSIONS: PAD is a highly effective strategy for patients with sudden cardiac arrest due to ventricular fibrillation who arrest in public places where AEDs are installed. Community responders who travel with an AED are less effective, but offer some prospect of resuscitation for many patients who would otherwise receive no treatment. Both strategies merit continuing development.

Quality of life after coronary angioplasty or continued medical treatment for angina: three-year follow-up in the RITA-2 trial. Randomized Intervention Treatment of Angina.

OBJECTIVES: We sought to evaluate the impact of percutaneous transluminal coronary angioplasty (PTCA) and medical treatment on self-perceived quality of life among patients with angina. BACKGROUND: The second Randomized Intervention Treatment of Angina trial (RITA-2) implemented initial policies of PTCA or continued medical treatment in patients with angina, allowing assessment of long-term health consequences. METHODS: A total of 1,018 patients were randomly assigned (504 to PTCA and 514 to medical treatment). The short form 36 (SF-36) self-administered quality-of-life questionnaire was completed at randomization and three months, one year and three years later. To date, 98% of patients reached one year and 67% reached three years. RESULTS: The PTCA group had significantly greater improvements in physical functioning, vitality and general health at both three months and one year, but not at three years. These quality-of-life scores were strongly related to breathlessness, angina grade and treadmill exercise time both at baseline and at one year. The treatment differences in quality of life are explained by the PTCA group's improvements in breathlessness, angina and exercise time. The attenuation of treatment difference at three years is partly attributed to 27% of medically treated patients receiving nonrandomized interventions in the interim. For both groups, there were also improvements in ratings of physical role functioning, emotional role functioning, social functioning, pain and mental health, but for these the superiority of PTCA over medical treatment was less pronounced. After one year, 33% and 22% of the PTCA and medical groups, respectively, rated their health much better. CONCLUSIONS: Coronary angioplasty substantially improves patient-perceived quality of life, especially physical functioning and vitality, as compared with continued medical treatment. These differences are attributed to alleviation of cardiac symptoms (specifically, breathlessness and angina), but must be balanced against the small procedure-related risks of PTCA.

Unanswered questions in thrombolysis.

Data available experimentally and from major trials suggest that the beneficial effects of thrombolysis depend on more than simple reperfusion. New knowledge regarding the dynamic nature of clot formation and clot lysis enables us to understand more of the processes involved in thrombolysis. The breakdown of systemic fibrinogen may be important because of the anticoagulant effect this can produce. Other beneficial effects of thrombolysis remain unproved or obscure. It is unlikely that any thrombolytic agent can be completely free of risk because no distinction is possible between a hemostatic plug and a pathologic thrombus. There may, however, be differences between agents in the likelihood of reocclusion. The value of active intervention with angioplasty or bypass grafting after thrombolysis remains undefined. Three major trials suggest that little erosion of initial benefit occurs over the first 12 months even when management is largely conservative. If thrombolysis leads to smaller infarct size, however, prognosis should be influenced favorably over a prolonged period. Parallel mortality curves between treated and placebo groups therefore suggest that some attrition is occurring to counteract what might otherwise be continuing prognostic benefit. The ideal thrombolytic agent should be inexpensive to manufacture, have a low risk of hemorrhagic complications, be nonallergenic, provide rapid and complete thrombolysis, have some anticoagulant properties, be easy to administer and suitable for readministration. However, a low risk of hemorrhage is probably incompatible with effective thrombolysis. A comparison of mortality results with the 3 existing agents are awaited with interest.

Evolution of late potential activity in the first six weeks after acute myocardial infarction.

The evolution of surface ventricular late potential activity was studied in 50 patients during the 6 weeks after first acute myocardial infarction (AMI). In 15 of 47 patients (32%) late potential activity appeared within 6 hours of the onset of major symptoms. Its prevalence overall remained approximately 30% at each recording time but with marked individual variability in appearance. Late potential activity was associated with late ventricular arrhythmias (greater than 24 hours after AMI) but not with early ventricular arrhythmias (less than 24 hours after AMI). Late ventricular arrhythmias or sudden death occurred only in the 6 patients with late potential activity (p less than 0.05). Early ventricular fibrillation (15 patients) occurred equally in the patients with and without late potential activity. Thus, late potential activity occurs at some stage in the first 6 weeks after AMI in 50% of patients, but its timing is variable. It is a sensitive but not specific predictor of late ventricular arrhythmias and sudden death, but not of early ventricular fibrillation.

Combined receptor intervention and myocardial infarction.

The aims of treatment in acute myocardial infarction are to limit evolving muscle necrosis, prevent heart failure, maintain electrical stability, and preserve the coronary circulation to avoid progressive or recurrent infarction. No single treatment achieves all these objectives. The rationale for the use of adrenoceptor blocking drugs is that they will oppose the effects of the increased sympathomimetic activity which follows acute infarction and which may adversely affect outcome. More is known of the clinical use of pure beta-blockade than of combined alpha- and beta-blockade with labetalol but in theory combined receptor blockade will produce additional beneficial effects over beta-blockade alone. beta-Adrenoceptor antagonists have a theoretical role in limiting infarct size. They may reduce the oxygen deficit of jeopardised though potentially viable tissue, limiting infarct size by their favourable effect on heart rate, systolic pressure, contractility, and metabolic pathways. That beta-blockade reduces myocardial damage has been confirmed in animal studies. Studies in man using enzyme release or R wave scoring as indicators of infarct size also suggest that oral or intravenous beta-blockers after infarction encourage myocardial salvage. Few studies have been reported in which the effects of combined alpha- and beta-blockade on infarct size have been determined. The actions of a dual blocking agent are more complex and the outcome less predictable than from beta-blockade alone: the advantages of the beta-blocking component will be retained while the alpha-blocking component may conceivably further diminish oxygen demand by reducing systolic pressure and heart size. Less favourably, coronary perfusion pressure may also fall. It is apparent that further clinical studies are needed. Adrenergic blockade may be used to prevent or treat ventricular arrhythmias which develop after infarction in the face of heightened sympathetic tone and continued ischaemia. Clinical and experimental evidence points to the efficacy of beta-blockade in ischaemia-related arrhythmias, but beta-blockade alone is probably ineffective against arrhythmias arising during reperfusion. In experimental studies, alpha-blockers are effective against both forms of arrhythmia although the doses required for reperfusion effects may produce unacceptable hypotension in clinical use. It is possible that combined alpha- and beta-blockade may have broader antiarrhythmic activity than beta-blockers alone but present clinical data on the value of labetalol in controlling postinfarction arrhythmias are sparse.(ABSTRACT TRUNCATED AT 400 WORDS)

Ocular changes resulting from therapy with amiodarone.

Amiodarone, a powerful antiarrhythmic agent recently made available in Britain, is known to cause corneal changes, but the clinical implications of this unwanted effect are still controversial. We have made serial observations on 105 patients treated with the drug for periods ranging from 3 months to over 7 years. Corneal abnormalities were detected by slit-lamp examination in 103 patients (98%). These always progressed over several months but subsequently showed a stable pattern which changed only with alteration of dose. The abnormalities regressed and disappeared within 7 months in the 16 patients whose treatment was discontinued for reasons unconnected with ocular changes. No macular changes or permanent sequelae occurred. Ocular symptoms were unusual: 6 patients had reactions in the skin of the eyelids, and 6 others had minor symptoms related to the corneal changes. We do not believe that ophthalmological surveillance is mandatory in asymptomatic patients on long-term amiodarone therapy.

Electrical injury to the heart may cause long-term damage to conducting tissue: a hypothesis and review of the literature.

Electrical injury, particularly alternating current, may lead to disease of conducting tissue, myocardial damage or may cause sudden cardiac death. Subtle abnormalities, particularly of sinus node function, may pose diagnostic difficulties and may not present for many years. The long-term follow-up of patients, perhaps as part of a registry, will help to define the clinical spectrum of cardiac presentations of electrical injury.

Automated external defibrillation: laboratory evaluation.

Twelve samples of ventricular fibrillation were fed into nine automated external defibrillator-pacemakers ( AEDP , "Heart Aid") of recent design. All the devices recognised and defibrillated ventricular fibrillation in seven of the samples within 30 sec. None of the devices reacted to two of the samples; in the remaining three there was inter-device variation ranging from an appropriate response to no response, as well as inappropriate pacing or delay in recognition and treatment. Poor recognition of some ventricular fibrillation waveforms with considerable inter-device variation limits the usefulness of this model. A new prototype responded more consistently and future models may be of value in community resuscitation. The difficulty of evaluating the diagnostic capability of AEDP devices in clinical use makes comprehensive laboratory testing essential prior to release.

Multiple microemboli after disintegration of clot during thrombolysis for acute myocardial infarction.

Seven of 475 consecutive patients treated with thrombolysis for acute myocardial infarction had severe embolic complications that were believed to be caused by disintegration of pre-existing clot. Three patients had symptoms that persisted for many weeks, and five died. Any potential site of pre-existing blood clot within the vascular system, notably an enlarged left atrium, ventricular aneurysm, or aortic aneurysms, should be regarded as a contraindication to treatment with thrombolytic agents.

A comparison of aspirin and anticoagulation following thrombolysis for myocardial infarction (the AFTER study): a multicentre unblinded randomised clinical trial.

OBJECTIVE: To compare aspirin with anticoagulation with regard to risk of cardiac death and reinfarction in patients who received anistreplase thrombolysis for myocardial infarction. DESIGN: A multicentre unblinded randomised clinical trial. SETTING: 38 hospitals in six countries. SUBJECTS: 1036 patients who had been treated with anistreplase for myocardial infarction were randomly assigned to either aspirin (150 mg daily) or anticoagulation (intravenous heparin followed by warfarin or other oral anticoagulant). The trial was stopped earlier than originally intended because of the slowing rate of recruitment. MAIN OUTCOME MEASURE: Cardiac death or recurrent myocardial infarction at 30 days. RESULTS: After 30 days cardiac death or reinfarction, occurred in 11.0% (57/517) of the patients treated with anticoagulation and 11.2% (58/519) of the patients treated with aspirin (odds ratio 1.02, 95% confidence interval 0.69 to 1.50, P = 0.92). Corresponding findings at three months were 13.2% (68/517) and 12.1% (63/519) (0.91, 0.63 to 1.32, P = 0.67). Patients receiving anticoagulation were more likely than patients receiving aspirin to have had severe bleeding or a stroke by three months (3.9% v 1.7% (0.44, 0.20 to 0.97, P = 0.04)). CONCLUSION: No evidence of a difference in the incidence of cardiac events was found between the two treatment groups, though the trial is too small to claim treatment equivalence confidently. A higher incidence of severe bleeding events and strokes was detected in the group receiving anticoagulation, suggesting that aspirin may be the drug of choice for most patients in this context.

Survey of 3765 cardiopulmonary resuscitations in British hospitals (the BRESUS Study): methods and overall results.

OBJECTIVE: To determine the circumstances, incidence, and outcome of cardiopulmonary resuscitation in British hospitals. DESIGN: Hospitals registered all cardiopulmonary resuscitation attempts for 12 months or longer and followed survival to one year. SETTING: 12 metropolitan, provincial, teaching, and non-teaching hospitals across Britain. SUBJECTS: 3765 patients in whom a resuscitation attempt was performed, including 927 in whom the onset of arrest was outside the hospital. MAIN OUTCOME MEASURE: Survival after initial resuscitation, at 24 hours, at discharge from hospital, and at one year, calculated by the life table method. RESULTS: There were 417 known survivors at one year, with 214 lost to follow up. By life table analysis for every eight attempted resuscitations there were three immediate survivors, two at 24 hours, 1.5 leaving hospital alive, and one alive at one year. Survival at one year was 12.5% including out of hospital cases and 15.0% not including these cases. Each hospital year averaged 30 survivors at one year: three who had an arrest outside hospital, seven who had one in the accident and emergency department, seven in the cardiac care unit, 10 in the general wards, and three in other, non-ward areas. Within the hospitals survival rates were best in those who had an arrest in the accident and emergency department, the cardiac care unit, or other specialised units. Outcome varied 12-fold in subgroups defined by age, type of arrest, and place of arrest. CONCLUSION: 71% of the mortality at one year in patients undergoing attempted resuscitation occurred during the initial arrest. Hospital resuscitation is life saving and cost effective and warrants appropriate attention, training, coordination, and equipment.