Determinants and outcomes of coronary angiography after non-ST-segment elevation myocardial infarction. A cohort study of the Myocardial Ischaemia National Audit Project (MINAP).

OBJECTIVE: To investigate determinants of, and outcomes from, coronary angiography and intervention in patients with non-ST-segment elevation myocardial infarction (NSTEMI). DESIGN: Observational study. SETTING: 44 British hospitals with interventional facilities. PATIENTS: 13,489 admissions with NSTEMI; July 2005 to December 2006. MAIN OUTCOME MEASURES: Rate of angiography during index admission; death and readmission to hospital within 180 days. RESULTS: Significantly lower rates of angiography were seen for women, the elderly, the most deprived and those having cardiac, and most non-cardiac, comorbidities. Performance of angiography, compared with no angiography, was not associated with lower rate of readmission (multiple adjusted hazard ratio (HR) = 0.96, 95% CI 0.74 to 1.24) unless accompanied by coronary intervention (HR = 0.73, 95% CI 0.56 to 0.95). Angiography was associated with reduction in 180-day mortality for survivors of hospitalisation (HR = 0.59, 95% CI 0.49 to 0.72); with greater reduction when followed by an intervention (HR = 0.34, 95% CI 0.28 to 0.42). This mortality benefit after intervention was seen both in women (HR = 0.42, 95% CI 0.29 to 0.60) and men (HR = 0.31, 95% CI 0.24 to 0.41), and across age groups: <65 years (HR = 0.25, 95% CI 0.14 to 0.44), 65-79 years (HR = 0.29, 95% CI 0.22 to 0.39) and > or =80 years (HR = 0.52, 95% CI 0.37 to 0.74). Mortality benefit was not significantly attenuated by the presence of comorbidities. CONCLUSION: Performance of angiography and coronary intervention after NSTEMI was associated with mortality benefit that persisted in the presence of both cardiac and non-cardiac comorbidities. Mortality benefit was seen across age groups and was similar for both sexes.

Evaluation of risk scores for risk stratification of acute coronary syndromes in the Myocardial Infarction National Audit Project (MINAP) database.

OBJECTIVE: To compare the discriminative performance of the PURSUIT, GUSTO-1, GRACE, SRI and EMMACE risk models, assess their performance among risk supergroups and evaluate the EMMACE risk model over the wider spectrum of acute coronary syndrome (ACS). DESIGN: Observational study of a national registry. SETTING: All acute hospitals in England and Wales. PATIENTS: 100 686 cases of ACS between 2003 and 2005. MAIN OUTCOME MEASURES: Model performance (C-index) in predicting the likelihood of death over the time period for which they were designed. The C-index, or area under the receiver-operating curve, range 0-1, is a measure of the discriminative performance of a model. RESULTS: The C-indexes were: PURSUIT C-index 0.79 (95% confidence interval 0.78 to 0.80); GUSTO-1 0.80 (0.79 to 0.81); GRACE in-hospital 0.80 (0.80 to 0.81); GRACE 6-month 0.80 (0.79 to 0.80); SRI 0.79 (0.78 to 0.80); and EMMACE 0.78 (0.77 to 0.78). EMMACE maintained its ability to discriminate 30-day mortality throughout different ACS diagnoses. Recalibration of the model offered no notable improvement in performance over the original risk equation. For all models the discriminative performance was reduced in patients with diabetes, chronic renal failure or angina. CONCLUSION: The five ACS risk models maintained their discriminative performance in a large unselected English and Welsh ACS population, but performed less well in higher-risk supergroups. Simpler risk models had comparable performance to more complex risk models. The EMMACE risk score performed well across the wider spectrum of ACS diagnoses.

Predictors of in-hospital mortality for patients admitted with ST-elevation myocardial infarction: a real-world study using the Myocardial Infarction National Audit Project (MINAP) database.

OBJECTIVE: Although early thrombolysis reduces the risk of death in STEMI patients, mortality remains high. We evaluated factors predicting inpatient mortality for patients with STEMI in a "real-world" population. DESIGN: Analysis of the Myocardial Infarction National Audit Project (MINAP) database using multivariate logistic regression and area under the receiver operating curve analysis. SETTING: All acute hospitals in England and Wales. PATIENTS: 34 722 patients with STEMI from 1 January 2003 to 31 March 2005. RESULTS: Inpatient mortality was 10.6%. The highest odds ratios for inpatient survival were aspirin therapy given acutely and out-of-hospital thrombolysis, independently associated with a mortality risk reduction of over half. A 10-year increase in age doubled inpatient mortality risk, whereas cerebrovascular disease increased it by 1.7. The risk model comprised 14 predictors of mortality, C index = 0.82 (95% CI 0.82 to 0.83, p<0.001). A simple model comprising age, systolic blood pressure (SBP) and heart rate (HR) offered a C index of 0.80 (0.79 to 0.80, p<0.001). CONCLUSION: The strongest predictors of in-hospital survival for STEMI were aspirin therapy given acutely and out-of-hospital thrombolysis, Previous STEMI models have focused on age, SBP and HR We have confirmed the importance of these predictors in the discrimination of death after STEMI, but also demonstrated that other potentially modifiable variables impact upon the prediction of short-term mortality.

Improving care for patients with acute coronary syndromes: initial results from the National Audit of Myocardial Infarction Project (MINAP).

OBJECTIVE: To describe the improvements in care that have followed the introduction of an electronic data entry and analysis system providing contemporary feedback on the management of acute coronary syndromes in 230 hospitals in England and Wales. DESIGN: Observational study METHODS: A secure electronic system was used to transfer encrypted data on patients with acute coronary syndromes from collaborating hospitals to central servers for analysis. Immediate online data entry to the central servers by hospitals allowed contemporary analyses of performance and immediate comparison with the national aggregate performance. RESULTS: The records of 156 902 patients receiving a final diagnosis of acute coronary syndrome during three years between October 2000 and September 2003 were analysed. Of 69 113 patients with ST segment elevation infarction, 75.4% received thrombolytic treatment. Between the first and last years of the study the median interval from hospital arrival to treatment fell for eligible patients from 38 (interquartile range 22-58) to 20 (interquartile range 14-28) minutes. By mid 2003 77.6% were receiving thrombolytic treatment within 30 minutes of arrival. The proportion treated within two hours of onset of symptoms increased from 32.5% to 40.3% (a difference of 7.8 percentage points, p < 0.0001). The use of secondary prevention medication for acute coronary syndromes increased over this period: angiotensin converting enzyme inhibitors, 62.4% to 72.4%; beta blockers, 76.3% to 82.6%; statins, 69.6% to 83.8%; and aspirin, 89.3% to 90.2%. CONCLUSION: The provision of contemporary online performance analyses has underpinned substantial improvement in the care of patients with acute coronary syndromes.

Can successful treatment of cardiac arrest be a performance indicator for hospitals?

BACKGROUND: Although resuscitation from cardiac arrest prevents more deaths from acute myocardial infarction (MI) than any other treatment, results have not been audited widely nor performance standards proposed. METHODS: The Myocardial Infarction National Audit Project (MINAP) uses electronic transmission of a 53-item dataset to a central cardiac audit database (CCAD). From October 2000 to August 2002, transmission by 218 hospitals of data from 55,906 cases of MI with 4934 attempted resuscitations from a first arrest, allowed for examination of factors determining survival, and for possible future measurement of success in resuscitation as a performance indicator. We investigated two possible indicators: (i) numbers of survivors from arrest in ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) per 1000 cases of MI; and (ii) observed/expected (O/E) ratios for survival taking all VF/VT arrests rather than MI as the denominator, and adjusting for differing age structures and admission delays among individual hospitals. FINDINGS: Of the 4934 reported patients suffering a first arrest, 1778 (36%) survived to be discharged from hospital. The presenting rhythm was VF/VT in 2321 (47%) patients of whom 1461 (63%) survived. Survival for all 218 hospitals together had the relatively small 95% confidence limits of 26 (25-27) survivors from VF/VT per 1000 MI. However, the small numbers from individual hospitals made it impossible in most cases, whichever of the two indicators was used, to separate quality of performance and completeness of reporting from the factor of chance. INTERPRETATION: Audit of success in resuscitation is essential if performance in the treatment of MI is to be assessed. However, the relatively small numbers of arrests occurring in individual hospitals means that if year on year improvements are to be documented, audit must be carried out among groups of hospitals or on a national scale.

Trends in the provision of thrombolytic treatment between 1993 and 1997. Myocardial Infarction Audit Group.

OBJECTIVE: To evaluate trends in provision of thrombolytic treatment between 1993 and 1997. DESIGN: Observational study. SUBJECTS: 3714 patients in 15 UK hospitals who had an admission diagnosis of myocardial infarction. MAIN OUTCOME MEASURES: Changes in prehospital and hospital delay before thrombolytic treatment; use of emergency services. RESULTS: Between 1993 and 1997 the proportion of patients who called for help within 30 minutes of the onset of symptoms fell from 42.6% to 36.0%; difference 6.6% (95% confidence intervals (CI) 3.3% to 10%). The direct use of the emergency service by patients and by doctors sending an ambulance without seeing the patient increased by 18.9%. Patients given thrombolytic treatment within 90 minutes of calling for help increased from 28.2% to 39.1%; difference 10.9% (95% CI 7.2% to 14.7%). Over the same period the proportion of patients treated in emergency departments increased from 4.4% to 17.3%, and the median delay from arrival to treatment in emergency departments fell from 53 to 36 minutes. Median delays for patients treated in cardiac care units after assessment in the emergency department fell from 63 to 54 minutes. CONCLUSION: Between 1993 and 1997 there was an increase in the proportion of patients with definite infarction having thrombolytic treatment within 90 minutes of a call for help. This was mainly the result of greater use of the emergency service and more rapid treatment of a larger proportion of eligible patients in emergency departments. Longer delays by patients have cancelled out some of this improvement.

Thrombolytic treatment for myocardial infarction: an examination of practice in 39 United Kingdom hospitals. Myocardial Infarction Audit Group.

OBJECTIVE: To examine use of thrombolytic drugs for myocardial infarction and use of contraindications to treatment in the United Kingdom. DESIGN: Observational study, based on a continuing audit. SETTING: 39 hospitals in the United Kingdom. PATIENTS: 30,029 patients admitted between November 1992 and June 1995 with suspected myocardial infarction. RESULTS: Of 13,628 patients with a final diagnosis of definite myocardial infarction 10,316 (75.7%) were considered eligible for thrombolytic treatment on the basis of typical cardiographic changes or new left bundle branch block. Of these, 8139 (59.7%) were diagnosed at admission to hospital and 6991 (85.9%) were administered thrombolytic drugs; 14.1% were considered too late for treatment or had a clinical contraindication. In 2177 patients (16% of 13,628)-thrombolytic treatment was given in the absence of contraindications and after the diagnosis of infarction had been confirmed by further electrocardiographic evidence. A further 591 (4.3%) with a final diagnosis of definite infarction without typical cardiographic changes also received thrombolytic treatment as did 1018 patients without a final diagnosis of definite infarction. In total, 9459 of 13,628 patients (71.6%) received thrombolytic treatment. The range of use of treatment between hospitals for a final diagnosis of infarction was 49.1-85.4%. This variation reflected differences in the frequency with which a diagnosis of definite myocardial infarction was made at admission, and the subsequent use of clinical contraindications to thrombolytic treatment. CONCLUSIONS: 75.7% of patients with a final diagnosis of definite myocardial infarction were eligible for thrombolytic treatment on the basis of cardiographic changes. Differences between hospitals in the frequency with which a diagnosis of infarction was made on admission, and differences in subsequent use of thrombolytic drugs, results in wide variation in treatment rates. Differences in use of thrombolytic treatment mainly reflect different thresholds for the use of clinical contraindications relating to haemorrhagic risk.

Planning for coronary angioplasty: guidelines for training and continuing competence. British Cardiac Society (BCS) and British Cardiovascular Intervention Society (BCIS) working group on interventional cardiology.

The following recommendations are made: 1 Existing centres undertaking angioplasty should increase their activity, and the target figure of 400 PTCA procedures per million of the United Kingdom population should be achieved by the end of 1996-97, or immediately thereafter. 2 Angioplasty centres should be appropriately equipped to undertake PTCA safely and effectively and provide a reliable emergency service. They should have a minimum of two trained PTCA operators jointly undertaking a minimum of 200 procedures per year at that centre, and have regular meetings to share experience. 3 Angioplasty operators should ensure that where the need arises patients undergoing PTCA can receive immediate attention from a trained operator at any time until discharge from hospital. 4 Trained operators should undertake at least 1-2 PTCA procedures per week (> 60 procedures per year) to maintain competence, and those undertaking so few procedures should increase their activity over the next three years to more than 100 a year. 5 Trainers should have performed at least 500 procedures before formally training others and should undertake a minimum of 125 procedures a year to maintain accreditation as a trainer. 6 Surgical cover for PTCA procedures should be mandatory and on site cover remains the strongly preferred option. Where surgical cover is provided off site, this should be at a centre less than 30 minutes away by road. Whether provided on or off-site it should be possible to establish cardiopulmonary bypass within 90 minutes of the decision being made to refer the patient for surgery. 7 All operators and interventional centres should audit their activity and results, review these data locally with colleagues, and provide regular audit returns to the national database run by BCIS. This will allow future recommendations concerning standards to take more account of risk stratification and actual outcomes, and not place such emphasis merely on volumes of activity. 8 These recommendations should be reviewed in three years.

Time delays in provision of thrombolytic treatment in six district hospitals. Joint Audit Committee of the British Cardiac Society and a Cardiology Committee of Royal College of Physicians of London.

OBJECTIVE: To measure the delays between onset of symptoms and admission to hospital and provision of thrombolysis in patients with possible acute myocardial infarction. DESIGN: Observational study of patients admitted with suspected myocardial infarction during six months. SETTING: Six district general hospitals in Britain. SUBJECTS: 1934 patients admitted with suspected myocardial infarction. MAIN OUTCOME MEASURES: Route of admission to hospital and time to admission and thrombolysis. RESULTS: Patients who made emergency calls did so sooner after onset of symptoms than those who called their doctor (median time 40 (95% confidence interval 30 to 52) minutes v 70 (60 to 90) minutes). General practitioners took a median of 20 (20 to 25) minutes to visit patients, rising to 30 (20 to 30) minutes during 0800-1200. The median time from call to arrival in hospital was 41 (38 to 47) minutes for patients who called an ambulance from home and 90 (90 to 94) minutes for those who contacted their doctor. The median time from arrival at hospital to thrombolysis was 80 (75 to 85) minutes for patients who were treated in the cardiac care unit and 31 (25 to 35) minutes for those treated in the accident and emergency department. CONCLUSION: The time from onset of symptoms to thrombolysis could be reduced substantially by more effective use of emergency services and faster provision of thrombolysis in accident and emergency departments.

Trial of early nifedipine in acute myocardial infarction: the Trent study.

Over 30 months 9292 consecutive patients admitted to nine coronary care units with suspected myocardial infarction were considered for admission to a randomised double blind study comparing the effect on mortality of nifedipine 10 mg four times a day with that of placebo. Among the 4801 patients excluded from the study the overall one month fatality rate was 18.2% and the one month fatality rate in those with definite myocardial infarction 26.8%. A total of 4491 patients fulfilled the entry criteria and were randomly allocated to nifedipine or placebo immediately after assessment in the coronary care unit. Roughly 64% of patients in both treatment groups sustained an acute myocardial infarction. The overall one month fatality rates were 6.3% in the placebo treated group and 6.7% in the nifedipine treated group. Most of the deaths occurred in patients with an in hospital diagnosis of myocardial infarction, and their one month fatality rates were 9.3% for the placebo group and 10.2% for the nifedipine group. These differences were not statistically significant. Subgroup analysis also did not suggest any particular group of patients with suspected acute myocardial infarction who might benefit from early nifedipine treatment in the dose studied.

Heart rate and QT interval in subjects adapted to beta-blockade: bradycardia and hypotension as uncorrelated adaptations.

Subjects in whom it was found that after a month's treatment with beta-blockers there was a fall of not less than 10 mmHg in systolic blood pressure persisting 54 h after cessation of treatment were considered to have "adapted". Significant falls of blood pressure and heart rate were observed, and were still present after two further weeks of treatment with placebo, but these adaptations were not correlated with each other. Fourteen hypertensive patients and five normotensive subjects received oral propranolol 80 mg, or metoprolol 100 mg, twice daily for 5 days. They were studied before treatment, and 54 h after the last dose. Drug administration was continued for a further 26 days, and the subjects were again examined 54 h after cessation of treatment. Blood was withdrawn at the times of study and contained negligible amounts of drug in the plasma. Records were made of blood pressure and ECG at rest and after exercise, the post-exercise QT being measured at a heart rate of exactly 100 beats per minute, obviating the need for any correction of QT. QT intervals were significantly prolonged, both at rest and on exercise. Responses to intravenous propranolol 10 mg or metoprolol 20 mg were also measured during the study periods, and no hypersensitivity to the drugs was found at rest or after exercise.

Identical twins with differing forms of ventricular pre-excitation.

Identical 10-year-old twins, both with electrocardiograms showing a short PR interval and a normal QRS complex but with dramatically different electrophysiological characteristics, are described. One twin experienced episodes of rapid palpitation and on one occasion was resuscitated from ventricular fibrillation. An intracardiac electrophysiological study confirmed the presence of an atrioventricular nodal bypass tract and in addition revealed the presence of an accessory atrioventricular pathway, thus demonstrating that the patient had both the Lown-Ganong-Levine and Wolff-Parkinson-White syndromes. Re-entry tachycardia and atrial fibrillation, with a very rapid ventricular rate, were precipitated. After treatment with amiodarone, the patient became asymptomatic and a repeat study showed that the features of the atrioventricular nodal bypass tract were no longer present and though re-entry tachycardias using the accessory atrioventricular pathway could still be induced, their rates were slower than before treatment. The other twin, in spite of an identical surface electrocardiogram, was asmymptomatic. An electrophysiological study showed the features of an atrioventricular nodal bypass tract but there was no evidence of additional atrioventricular accessory connections and a tachycardia could not be induced.

Dual effect of disopyramide on atrial and atrioventricular conduction and refractory periods.

Disopyramide has been shown in conditions of cholinergic blockade to have a depressant effect upon sinus node automaticity and the atrial refractoriness. It also prolongs atrioventricular conduction and increases atrioventricular refractoriness. These effects may often be masked in vivo by the anticholinergic effects of the drug.