To Examine the Effectiveness of a Hospital-Based Nurse-Led Secondary Prevention Clinic

Modification of cardiovascular risk factors can reduce the incidence of myocardial infarction (MI), effectively extend survival, decrease the need for interventional procedures, and improve quality of life in persons with known cardiovascular disease. Pharmacological treatments and important lifestyle changes reduce people's risks substantially (by 1/3 to 2/3) and can slow and perhaps reverse progression of established coronary disease. When used appropriately, these interventions are more cost-effective than many other treatments, currently provided by the National Health Service [Department of Health National Service Frameworks: coronary heart disease. Preventing coronary heart disease in high risk patients. 2000. HMSO.] Secondary prevention clinics are effective means by which to ensure targets are achieved and assist primary care in long-term maintenance of lifestyle change and drug optimisation.

A 2-year hospital-based pilot project was established at the Royal Hospitals, April 2001–April 2003. The aim of the project was to target patients with coronary heart disease, post-MI and/or coronary artery bypass grafting and/or percutaneous coronary intervention, 6 months following their cardiac event. The plan was to assess patient risk factors and medication a minimum of 6 months following their cardiac event to ascertain if government targets were being achieved; secondly, to examine the effectiveness of a hospital-based nurse-led secondary prevention clinic on modifying risk factors and optimising drug therapies.

Strategies to attenuate micro-vascular obstruction during P-PCI: the randomized reperfusion facilitated by local adjunctive therapy in ST-elevation myocardial infarction trial

Background

Microvascular obstruction (MVO) following primary percutaneous coronary intervention (PPCI) treatment of ST-segment elevation myocardial infarction (STEMI) contributes to infarct expansion, left ventricular (LV) remodelling, and worse clinical outcomes. The REFLO-STEMI trial tested whether intra-coronary (IC) high-dose adenosine or sodium nitroprusside (SNP) reduce infarct size and/or MVO determined by cardiac magnetic resonance (CMR).

Methods and results

REFLO-STEMI, a prospective, open-label, multi-centre trial with blinded endpoints, randomized (1:1:1) 247 STEMI patients with single vessel disease presenting within 6 h of symptom onset to IC adenosine (2–3 mg total) or SNP (500 μg total) immediately following thrombectomy and again following stenting, or to standard PPCI. The primary endpoint was infarct size % LV mass (%LVM) on CMR undertaken 24–96 h after PPCI (n = 197). Clinical follow-up was to 6 months. There was no significant difference in infarct size (%LVM, median, interquartile range, IQR) between adenosine (10.1, 4.7–16.2), SNP (10.0, 4.2–15.8), and control (8.3, 1.9–14.0), P = 0.062 and P = 0.160, respectively, vs. control. MVO (% LVM, median, IQR) was similar across groups (1.0, 0.0–3.7, P = 0.205 and 0.6, 0.0–2.4, P = 0.244 for adenosine and SNP, respectively, vs. control 0.3, 0.0–2.8). On per-protocol analysis, infarct size (%LV mass, 12.0 vs. 8.3, P = 0.031), major adverse cardiac events (hazard ratio, HR, 5.39 [1.18–24.60], P = 0.04) at 30 days and 6 months (HR 6.53 [1.46–29.2], P = 0.01) were increased and ejection fraction reduced (42.5 ± 7.2% vs. 45.7 ± 8.0%, P = 0.027) in adenosine-treated patients compared with control.

Conclusions

High-dose IC adenosine and SNP during PPCI did not reduce infarct size or MVO measured by CMR. Furthermore, adenosine may adversely affect mid-term clinical outcome.

Clinical Trial registration

ClinicalTrials.gov Identifier: NCT01747174; https://clinicaltrials.gov/ct2/show/NCT01747174

ST elevation on the exercise ECG in patients presenting with chest pain and no prior history of myocardial infarction

OBJECTIVE

To assess the aetiology, and prognosis of ST-segment elevation (STE) on the exercise electrocardiogram in patients with chest pain without a prior history of myocardial infarction (MI).

METHODS

Between January 1998 and December 2005, 14 941 exercise stress tests were performed to assess chest pain in patients without a prior history of MI. Those who developed STE were identified.

RESULTS

STE occurred in 0.78% (116/14 941). Coronary angiography was performed in 108 patients. All patients had at least one severe coronary artery stenosis (>70%). The site of STE on exercise ECG was shown to be 95.4% predictive of a severe stenosis in the coronary artery supplying that area. Lateral STE was rare (1/116). Ninety-eight patients underwent revascularisation; 67 patients had percutaneous coronary intervention (PCI) and 31 underwent coronary artery bypass grafting (CABG). Follow-up included recording of death, MI, cerebrovascular event, heart failure and target vessel revascularisation. The projected 7-year event-free survival probability was 62.1% for those undergoing CABG, 77.1% for those who had PCI and 68.6% for those not undergoing revascularisation (no difference between these three groups, log rank p = 0.802).

CONCLUSIONS

STE on the exercise ECG is rare but specific for ischaemic heart disease and is predictive of a severe stenosis in the corresponding coronary artery. Prognosis is favourable following revascularisation.

Biphasic energy selection for transthoracic cardioversion of atrial fibrillation. The BEST AF Trial

AIMS

To compare the efficacy and safety of an escalating energy protocol with a non-escalating energy protocol using an impedance compensated biphasic defibrillator for direct current cardioversion of atrial fibrillation (AF).

METHODS AND RESULTS

This prospective multicentre randomised trial enrolled 380 patients (248 male, mean (SD) age 67 (10) years) with AF. Patients were randomised to either an escalating energy protocol (protocol A: 100 J, 150 J, 200 J, 200 J), or a non-escalating energy protocol (protocol B: 200 J, 200 J, 200 J). Cardioversion was performed using an impedance compensated biphasic waveform. First-shock success was significantly higher for those randomised to 200 J than 100 J (71% vs 48%; p<0.01) and for patients with a body mass index (BMI) >25 kg/m(2) (75% vs 44%; p = 0.01). In patients with a normal BMI there was no significant difference in first-shock success. There was also no significant difference between subsequent shocks or overall success. The use of a non-escalating protocol (protocol B) resulted in fewer shocks but with a higher cumulative energy. There was no difference in duration of procedure, amount of sedation administered or post-shock erythema between the groups.

CONCLUSION

First-shock success was significantly higher, particularly in patients with a BMI >25 kg/m(2), when a non-escalating initial 200 J energy was selected. The overall success, duration of procedure and amount of sedation administered, however, did not differ significantly between the two protocols.

The obstacles to maximising the impact of public access defibrillation: an assessment of the dispatch mechanism for out-of-hospital cardiac arrest

OBJECTIVES

To determine the diagnostic accuracy of advanced medical priority dispatch system (AMPDS) software used to dispatch public access defibrillation first responders to out-of-hospital cardiac arrests (OHCA).

DESIGN

All true OHCA events in North and West Belfast in 2004 were prospectively collated. This was achieved by a comprehensive search of all manually completed Patient Report Forms compiled by paramedics, together with autopsy reports, death certificates and medical records. The dispatch coding of all emergency calls by AMPDS software was also obtained for the same time period and region, and a comparison was made between these two datasets.

SETTING

A single urban ambulance control centre in Northern Ireland.

POPULATION

All 238 individuals with a presumed or actual OHCA in the North and West Belfast Health and Social Services Trust population of 138 591 (2001 Census), as defined by the Utstein Criteria.

MAIN OUTCOME MEASURES

The accurate dispatch of an emergency ambulance to a true OHCA.

RESULTS

The sensitivity of the dispatch mechanism for detecting OHCA was 68.9% (115/167, 95% confidence interval (CI) 61.3% to 75.8%). However, the sensitivity for arrests with ventricular fibrillation (VF) was 44.4% (12/27) with sensitivity for witnessed VF of 47.1% (8/17). The positive predictive value was 63.5% (115/181, 95% CI 56.1% to 70.6%).

CONCLUSIONS

The sensitivity of this dispatch process for cardiac arrest is moderate and will constrain the effectiveness of Public Access Defibrillation (PAD) schemes which utilise it.

TRIAL REGISTRATION

controlled-trials.com ISRCTN07286796.

The Northern Ireland Public Access Defibrillation (NIPAD) study: effectiveness in urban and rural populations

OBJECTIVE

To assess the impact of mobile automated external defibrillators (AEDs) on out-of-hospital cardiac arrests (OHCAs) in urban and rural populations.

DESIGN

Prospective before and after intervention, population study.

SETTING

Urban and rural areas of 160,000 each. Patients, interventions and

MAIN OUTCOME MEASURES

In 2004-6 the demographics of OHCAs were assessed. In 2005-6 AEDs were deployed (29 urban, 53 rural): 335 urban first responders (FRs) and 493 rural FRs were trained in AED use and dispatched to OHCAs. Call-to-response interval (CRI), resuscitation and survival-to-discharge rates for OHCA were compared.

RESULTS

In 2004 there were 163 urban OHCAs and the emergency medical services (EMS) attended 158 (ventricular fibrillation (VF) 27/158 (17.1%)). In 2005-6 there were 226 OHCAs, EMS attended 216 (VF 30/216 (13.9%)). In 2005-6 FRs were paged to 128 OHCAs (56.6%), FRs attended 88/128 (68.8%): 18/128 (14.1%) reached before the EMS. The best combined FR/EMS mean (SD) CRI in 2005-6 (5 min 56 s (4)) was better than the EMS alone in 2004 (7 min (3); p = 0.002). Survival rate was 5.1% in 2004, 1.4% in 2005-6 (p = NS). In 2004 there were 131 rural OHCAs, EMS attended 121 (VF 19/121 (15.7%)). In 2005-6 there were 122 OHCAs, EMS attended 114 (VF 19/114 (16.7%)). In 2005-6 FRs were paged to 49 OHCAs, FRs attended 42/49 (85.7%): 23/49 (46.9%) reached before the EMS. The best combined FR/EMS mean (SD) CRI in 2005-6 (9 min 22 s (6)) was better than the EMS alone in 2004 (11 min 2 s (6); p = 0.018). Survival rate was 2.5% in 2004, 3.5% in 2005-6 (p = NS).

CONCLUSIONS

Despite improvement in CRI there was no impact on survival (witnessed arrest 32.8%, VF 15.6%).

TRIAL REGISTRATION NUMBER

ISRCTN07286796.

Giant true saphenous vein graft aneurysm causing cardiac compression: a rare cause of atrial flutter

A 67 year old man presented with new-onset atrial flutter. He had a history of coronary artery bypass graft (CABG) surgery on two occasions. Subsequent investigation revealed the presence of a large saphenous vein graft (SVG) aneurysm compressing the right heart. We postulate that the SVG aneurysm was the precipitating cause for the atrial flutter. This case is the first in the literature to document an atrial arrhythmia as the presenting feature of a SVG aneurysm.

Novel rectangular biphasic and monophasic waveforms delivered by a radiofrequency-powered defibrillator compared with conventional capacitor-based waveforms in transvenous cardioversion of atrial fibrillation

AIMS

To investigate the feasibility and efficacy of novel low-tilt biphasic waveforms in transvenous cardioversion of atrial fibrillation (AF), delivered by a radiofrequency-powered defibrillator.

METHODS AND RESULTS

The investigation was performed in three phases in an animal model of AF: a feasibility and efficacy study (in 10 adult Large White Landrace swine), comparison with low-tilt monophasic and standard capacitor-based waveforms, and an assessment of sequential shocks delivered over several pathways (in 15 adult Suffolk sheep). Defibrillation electrodes were positioned transvenously under fluoroscopic control in the high lateral right atrium and distal coronary sinus. When multiple defibrillation pathways were tested, a third electrode was also attached to the lower interatrial septum. The electrodes were then connected to a radiofrequency (RF)-powered defibrillator or a standard defibrillator. After confirmation of successful induction of sustained AF, defibrillation was attempted. Percentage success was calculated from the effects of all shocks delivered to all the animals within each set of experiments. Of the low-tilt (RF) biphasic waveforms delivered during internal atrial cardioversion, 100% success was achieved with a 6/6 ms 100/-50 V waveform (1.45+/-0.01 J). This waveform was similar in efficacy to low-tilt (RF) monophasic waveforms (88 vs. 92% success, 1.58+/-0.01 vs. 2.67+/-0.03 J; P=NS; delivered energy 41% lower) and superior to equivalent voltage standard monophasic (50% success, 0.67+/-0.00 J; P<0.001) and biphasic waveforms (72% success, 0.69+/-0.00 J; P=0.03). Sequential shocks delivered over dual pathways did not improve the efficacy of low-tilt biphasic waveforms.

CONCLUSION

A low-tilt biphasic waveform from a RF-powered defibrillator (6/6 ms 100/-50 V) is more efficacious than standard monophasic or biphasic waveforms (equivalent voltage) and is similar in efficacy to low-tilt monophasic waveforms.

Usefulness of body surface maps to demonstrate ventricular activation patterns during left ventricular pacing and reentrant activation during ventricular tachycardia in men with coronary heart disease and left ventricular dysfunction

Epicardial electrical events were reconstructed using an inverse model for left ventricular (LV) pacing and during ventricular tachycardia (VT) induced during implantation of a biventricular pacemaker and/or internal defibrillator. The electrocardiographic position of the pacing lead, determined from the region of most negative potential 30 ms after the pacing spike, was compared with the radiographic position. Activation characterized by isochronal maps was correlated with the echocardiographic/myocardial scintigraphic data. Reconstructed epicardial isopotential/isochronal maps during VT were used to determine the presence of reentry. In 7 patients during LV pacing, epicardial isopotential maps located the maximum negative potentials anterolaterally (n = 3), posterolaterally (n = 2), and posteriorly (n = 2). Isochronal maps demonstrated activation patterns including regions of delayed activation that, in 5 patients, correlated with areas of akinesia/hypokinesia or fixed defects on echocardiography/myocardial scintigraphy. The mean difference between the radiographically measured right ventricular to LV pacing lead distance and calculated electrocardiographic right ventricular to LV pacing site distance was 1.7 cm. During VT, induced in 5 patients, single-loop reentry was observed in 3 and figure-of-8 reentry in 2. Exit site and regions of fast/slow conduction and conduction block that correlated with anatomic areas of infarction defined by echocardiography/myocardial scintigraphy were demonstrated. In conclusion, epicardial maps reconstructed from the body surface map can identify LV pacing sites and demonstrate reentry during VT. The body surface map could thus identify optimal pacing sites for LV pacing and targets for VT ablation.

Demographic and temporal trends in out of hospital sudden cardiac death in Belfast

OBJECTIVE

To determine the epidemiology of out of hospital sudden cardiac death (OHSCD) in Belfast from 1 August 2003 to 31 July 2004.

DESIGN

Prospective examination of out of hospital cardiac arrests by using the Utstein style and necropsy reports. World Health Organization criteria were applied to determine the number of sudden cardiac deaths.

RESULTS

Of 300 OHSCDs, 197 (66%) in men, mean age (SD) 68 (14) years, 234 (78%) occurred at home. The emergency medical services (EMS) attended 279 (93%). Rhythm on EMS arrival was ventricular fibrillation (VF) in 75 (27%). The call to response interval (CRI) was mean (SD) 8 (3) minutes. Among patients attended by the EMS, 9.7% were resuscitated and 7.2% survived to leave hospital alive. The CRI for survivors was mean (SD) 5 (2) minutes and for non-survivors, 8 (3) minutes (p < 0.001). Ninety one (30%) OHSCDs were witnessed; of these 91 patients 48 (53%) had VF on EMS arrival. The survival rate for witnessed VF arrests was 20 of 48 (41.7%): all 20 survivors had VF as the presenting rhythm and CRI < or = 7 minutes. The European age standardised incidence for OHSCD was 122/100,000 (95% confidence interval 111 to 133) for men and 41/100,000 (95% confidence interval 36 to 46) for women.

CONCLUSION

Despite a 37% reduction in heart attack mortality in Ireland over the past 20 years, the incidence of OHSCD in Belfast has not fallen. In this study, 78% of OHSCDs occurred at home.

The role of biphasic shocks for transthoracic cardioversion of atrial fibrillation

The modern generation of transthoracic defibrillators now employ impedance compensated biphasic waveforms. These new devices are superior to those with monophasic waveforms and practice is currently switching to biphasic defibrillators for the treatment of both ventricular and atrial fibrillation. However, there is no universal guideline for the use of biphasic defibrillators in direct current cardioversion of atrial fibrillation. This article reviews the use of biphasic defibrillation waveforms for transthoracic cardioversion of atrial fibrillation.

Clopidogrel in non-ST segment elevation acute coronary syndromes: an overview of the submission by the British Cardiac Society and the Royal College of Physicians of London to the National Institute for Clinical Excellence, and beyond

A comprehensive appraisal was undertaken on behalf of the British Cardiac Society and the Royal College of Physicians of London to assess the use of clopidogrel in acute coronary syndromes. The appraisal was submitted to the National Institute for Clinical Excellence (NICE) in August 2003 and contributed to the development of the recently published guidelines for the use of clopidogrel in acute coronary syndromes. The submission to NICE and more recent publications evaluating the use of clopidogrel are reviewed.

Impedance compensated biphasic waveforms for transthoracic cardioversion of atrial fibrillation: a multi-centre comparison of antero-apical and antero-posterior pad positions

AIMS

To compare the success rate for transthoracic direct current cardioversion (DCC) of atrial fibrillation (AF) with antero-posterior (AP) and antero-apical (AA) electrode positions using an impedance compensated biphasic (ICB) waveform.

METHODS AND RESULTS

Three-hundred and seven patients [mean age 66 (SD+/-13), 195 male] with AF were recruited in three centres. Patients were randomized to an AA (n=150) or AP (n=144) pad position. Thirteen patients with implanted pacemakers were defaulted to the AP pad position. Cardioversion was performed using an ICB waveform with a 70, 100, 150, and 200 J energy selection protocol. If the fourth shock was unsuccessful, the pads were crossed over to the alternative position for a final 200 J shock. Shock 1 was successful in 54/150 (36%) AA and 45/144 (31%) AP patients, whereas success was achieved by shock 2 in 99/150 (66%) AA and 74/144 (51%) AP, by shock 3 in 123/150 (82%) AA and 109/144 (76%) AP, and by shock 4 in 143/150 (95%) AA and 127/144 (88%) AP and after cross-over in 144/150 (96%) AA and 135/144 (94%) AP. Overall success rate was higher than expected at 95%. Pad position was not associated significantly with success. There was a trend towards an improved outcome with the AA configuration (P=0.05).

CONCLUSION

The influence of pad position for DCC of AF may be less pertinent with ICB waveforms than with monophasic waveforms.

Percutaneous coronary intervention and 1 year survival in patients treated with fibrinolytic therapy for acute ST-elevation myocardial infarction

AIMS

To assess the predictors of 1 year mortality in patients treated with fibrinolytic therapy for ST-segment elevation myocardial infarction (STEMI) and to determine whether a strategy of early percutaneous coronary intervention (PCI) improves outcome.

METHODS AND RESULTS

Consecutive patients (n = 474) admitted to our unit (1998-2001) with STEMI were treated with fibrinolytic therapy. For each patient, age, gender, admission via mobile coronary care unit (MCCU), infarct location, initial systolic blood pressure and Killip class, prior history of ischaemic heart disease, hypertension, diabetes mellitus, smoking status, family history, hyperlipidaemia, and in-hospital PCI (n = 154) were recorded. Mortality at 1 year was obtained from medical records (n = 473). Binary logistic regression analysis was performed to determine independent predictors of 1 year mortality. Mortality in the non-PCI group was 21 vs. 7% in the PCI group. Independent predictors of 1 year mortality were age (risk ratio 1.12, 95% CI 1.08-1.15, P < 0.0001), initial SBP < or = 80 mmHg (risk ratio 4.34, 95% CI 1.68-11.2, P = 0.002), initial Killip class > or = 3 (risk ratio 2.97, 95% CI 1.42-6.2, P = 0.004), and lack of in-hospital PCI (risk ratio 0.39, 95% CI 0.19-0.81, P = 0.012). Although the PCI group were younger (P = 0.007), more likely to be admitted via the MCCU (P = 0.008), with a shorter pain to needle time (P = 0.04), multivariable analysis adjusted for these differences.

CONCLUSION

In-hospital PCI in patients treated with fibrinolytic therapy for STEMI is associated with a substantial reduction in 1 year mortality.

Considerations in combination therapy: fibrinolytics plus glycoprotein IIb/IIIa receptor inhibitors in acute myocardial infarction

The combined use of a fibrinolytic and a platelet glycoprotein (GP) IIb/IIIa receptor inhibitor to target the fibrin and platelet components of occlusive thrombi offers the potential for more rapid and complete reperfusion in patients with acute myocardial infarction (MI), although there have been concerns about the safety of this combination therapy. Data from the recent GUSTO-V and the ASSENT-3 trials support the use of this regimen in that the 30-day death or nonfatal reinfarction rate (7 days) in GUSTO-V and death or in-hospital reinfarction or in-hospital refractory ischemia rate in ASSENT-3 were reduced (p = 0.001 and p = 0.0001, respectively). The need for revascularization in both these trials was also reduced significantly. There was no increased risk of intracranial hemorrhage or stroke with the combination therapy, but an increased rate of nonintracranial severe or major bleeding was observed. At present, patients aged > 75 years should not receive combination therapy. Further studies in subgroup patient populations are warranted.

Prehospital 80-LAD mapping: Does it add significantly to the diagnosis of acute coronary syndromes?

Early detection of acute myocardial infarction (MI) is vital in the management of acute coronary syndromes (ACS). Hence we compared the diagnostic capability of the standard 12-lead electrocardiogram (ECG) with the 80-lead ECG body surface map (BSM) prehospital.

METHODS

Consecutive patients (n = 294) presenting prehospital with ischemic type chest pain were included. All had an ECG and BSM pretreatment and a baseline and 12-hour cardiac troponin-T or I (cTnT or cTnI). Acute MI was defined as cTnT > 0.09 or cTnI > 0.1 ng/mL. Acute MI on the BSM was defined as ST elevation measured at the J-point, > or = 1 mm inferior/right ventricular/high right anterior/lateral regions, > or = 2 mm anterior region, > or = 0.5 mm posterior region.

RESULTS

Acute MI occurred in 182/294 (62%) based on cTnT or I. ST elevation on the standard ECG predicted acute MI in 103 (sensitivity 57%, specificity 94%; c-statistic 0.73). The optimal model for the standard ECG included ST elevation, summed ST depression and past history of MI (c-statistic 0.82; Chi-square (Wald) 120.7, 3df). The BSM predicted acute MI in 146 (sensitivity 80%, specificity 92%; c-statistic 0.86). The optimal model for the BSM included BSM criteria for acute MI and past history of MI (c-statistic 0.91; Chi-square (Wald) 180.3, 2df).

CONCLUSION

The 80-lead BSM is superior to the standard 12-lead ECG in predicting acute MI prehospital.

Efficacy of distinct energy delivery protocols comparing two biphasic defibrillators for cardiac arrest

Limited data have been published on the use of external defibrillators that deliver impedance compensated biphasic (ICB) waveforms in patients. We compared 2 ICB defibrillators, the Heartstream XL (150-150-150 J protocol) and Heartsine Samaritan (100-150-200 J protocol) in 78 consecutive patients in cardiac arrest. The performance of the 2 devices over the first 2 shocks was statistically equivalent. By the third shock, the Heartsine Samaritan had significantly better performance in removing ventricular fibrillation (p = 0.029). Energy selection for ICB waveforms requires further validation.

Managing high-risk patients with acute coronary syndromes: the Prospective Registry of Acute Ischaemic Syndromes in the UK (PRAIS-UK)

A study was carried out to find out whether more intense treatment (both medical and revascularisation) is targeted towards higher-risk patients with acute coronary syndromes. A prospective UK registry of patients admitted with non-ST elevation acute coronary syndromes was established to examine practice patterns and clinical outcomes with respect to the risk profile of the patients. Clinically important high-risk subgroups included the elderly, diabetics, those with heart failure and those with ST depression or bundle branch block on the presenting ECG. Elderly patients were less likely to receive evidence-based treatments, including beta blockers, statins and revascularisation. Diabetics received more revascularisation procedures but the overall revascularisation rate was low. Heart failure patients received less evidence-based treatment, with the exception of angiotensin-converting enzyme (ACE) inhibitors. Heparin was used less frequently in those with a normal ECG, although rates of revascularisation were not different when compared with those with ECG abnormalities. The conclusions of the study were that groups of patients with particularly high event rates are readily identified by their clinical characteristics, but use of evidence-based treatments and invasive investigations do not appear to be targeted towards those at greatest risk. Risk stratification and the appropriate application of treatments for patients with acute coronary syndromes need to be reviewed in the clinical setting.

Body surface potential mapping improves detection of ST segment alteration during percutaneous coronary intervention

BACKGROUND

The 12-lead electrocardiogram underestimates ST segment alteration in acute coronary syndromes compared with multi-lead body surface mapping. We assessed whether 80-lead mapping would improve detection of ST alteration during percutaneous coronary intervention.

METHODS

Simultaneous maps and 12-lead electrocardiograms were recorded pre-procedure, during balloon inflation and post-procedure from patients undergoing elective intervention to native coronary arteries. Recordings were obtained from 39 inflations (19 patients). All arteries were successfully stented.

RESULTS

Mean 'lead specific' ST alteration (the difference in ST elevation/depression between pre-procedure and inflation recordings in the lead showing maximal ST alteration) was greater on the map than on electrocardiogram, both for ST elevation (0.16+/-0.02 vs. 0.06+/-0.01 mV; p<0.001) and ST depression (0.11+/-0.017 vs. -0.03+/-0.006 mV; p<0.001). During first inflations (n=19), mean lead specific ST elevation and depression on map were greater than on electrocardiogram (0.20+/-0.034 vs. 0.07+/-0.015 mV; p<0.001 and 0.11+/-0.029 vs. 0.03+/-0.009 mV; p=0.001, respectively). Mapping detected greater summated ST elevation and depression during inflation than electrocardiogram (0.04+/-0.005 vs. 0.021+/-0.003 mV; p<0.001 and 0.026+/-0.004 vs. 0.011+/-0.002 mV; p<0.001, respectively). Qualitative analysis of maps and electrocardiograms showed that 21/39 (53.8%) maps recorded during inflation met criteria for myocardial ischaemia compared with 7/39 (17.9%) electrocardiograms (p<0.001).

CONCLUSION

Body surface mapping compared with the 12-lead electrocardiogram improves detection of myocardial ischaemia during intervention.

Novel uses for recombinant erythropoietin therapy in unlicensed indications

Clinical uses for recombinant human erythropoietin (rHuEPO) therapy continue to expand. Initial use was in anaemia associated with end-stage renal disease, but more recently there have been many reports of the benefits of erythropoietin in other clinical situations such as cancer-related anaemia. Recombinant erythropoietin reduces the need for blood transfusion and hence exposure to donor blood products as well as improving quality of life. We report four patients who were transfusion dependent, none of whom had licensed indications for the use of recombinant erythropoietin. Two patients had microangiopathic haemolytic anaemia secondary to mechanical valve haemolysis and were unsuitable for any further cardiac intervention. One patient had anaemia of chronic disease and anti-Vel red cell antibodies, making compatible blood transfusions difficult to obtain. The fourth patient had primary thrombocythaemia and developed transfusion-dependent anaemia secondary to myelosuppressive agents. All four patients had a relative deficiency in endogenous erythropoietin levels ranging between 7 and 41 IU/l. After commencing recombinant erythropoietin therapy, all had a response in haemoglobin of at least 1 g/dl with an overall improvement in their quality of life. We conclude that rHuEPO is a very convenient and useful form of treatment in transfusion-dependent anaemia and in some cases beyond the licensed indications.

Collaborative Angiographic Patency Trial Of Recombinant Staphylokinase (CAPTORS II)

AIMS

A fibrinolytic agent more effective than streptokinase available for bolus injection with reasonable cost-effectiveness is a desirable goal. Pilot studies with bolus pegulated staphylokinase (PEG-Sak) have revealed excellent Thrombolysis In Myocardial Infarction (TIMI) 3 60-minute flow.

METHODS AND RESULTS

We evaluated patients with acute ST-elevation myocardial infarction within 6 hours of chest pain onset to determine a dose of PEG-Sak that had at least equal efficacy to recombinant tissue plasminogen activator (rt-PA) while maintaining an acceptable safety profile. After the initial study of 38 patients, of whom 27 received PEG-Sak, enrollment was temporarily halted because 3 patients receiving PEG-Sak had intracranial hemorrhage: 1 at a dose of 0.15 mg/kg and 2 at a dose of 0.05 mg/kg. Overall, 378 patients were studied across a PEG-Sak dose range from 0.01 mg/kg to 0.015 mg/kg, and 122 patients received accelerated rt-PA. At the lowest dose of PEG-Sak studied, 0.01 mg/kg, there was suggestive evidence of attenuation of efficacy; the point estimate for TIMI 3 flow was 24% (95% CI 9%-38%). At doses of 0.01875 to 0.0375 mg/kg (n = 314), TIMI 3 flow rates were 33% (95% CI 27%-38%), whereas the TIMI 3 flow was 41% (95% CI 20%-61%) at the highest PEG-Sak dose studied, 0.05 mg/kg (n = 23), which was similar to that found with rt-PA, 41% (95% CI 32%-50%).

CONCLUSION

The efficacy of PEG-Sak, coupled with its ease of administration, provide further impetus for further study in acute myocardial infarction.

Body surface mapping improves early diagnosis of acute myocardial infarction in patients with chest pain and left bundle branch block

OBJECTIVE

To test prospectively depolarisation and repolarisation body surface maps (BSMs) for mirror image reversal, which is less susceptible to artefact, in patients with acute ischaemic-type chest pain, and to compare these BSM criteria with previously published 12 lead ECG criteria.

METHODS

An 80 lead portable BSM system was used to map patients presenting with acute ischaemic-type chest pain and a 12 lead ECG with left bundle branch block (LBBB). Acute myocardial infarction (AMI) was defined by serial cardiac enzymes. Each 12 lead ECG was assessed by the criteria of Sgarbossa et al and Hands et al for diagnosis of AMI. Depolarisation and repolarisation BSMs were assessed for loss of mirror image reversal of QRS with ST-T isointegral map patterns and a change in vector angle from QRS to ST-T outside 180+/-15 degrees -findings typically seen in LBBB with AMI.

RESULTS

Of 56 patients with chest pain and LBBB, 18 had enzymatically confirmed AMI. Patients with loss of BSM image reversal were significantly more likely to have AMI (odds ratio 4.9, 95% confidence interval 1.5 to 16.4, p = 0.007). Loss of BSM image reversal was significantly more sensitive (67%) for AMI than either 12 lead ECG method (17%, 33%) albeit with some loss in specificity (BSM 71%, 12 lead ECG 87%, 97%). Patients with AMI compared with those without AMI had a greater mean change in vector angle outside the normal range (180+/-15 degrees ), particularly between QRS isointegral and ST60 isopotential (the potential 60 ms after the J point at each electrode site) BSMs (19 degrees v 9 degrees, p = 0.038). Loss of image reversal and QRS-ST60 vector change outside 180+/-15 degrees had 61% sensitivity and 82% specificity for AMI (odds ratio 7.0, 95% confidence interval 2.0 to 24.4, p = 0.001).

CONCLUSIONS

BSM compared with the 12 lead ECG improved the early diagnosis of AMI in the presence of LBBB.

Comparison of the 80-lead body surface map to physician and to 12-lead electrocardiogram in detection of acute myocardial infarction

Diagnosis of non-ST-elevation acute myocardial infarction (AMI) by a 12-lead electrocardiogram has poor sensitivity and specificity and, therefore, relies on biochemical markers of myocardial necrosis, which can only be reliably detected within 14 to 16 hours from symptom onset. The body surface map (BSM) improves AMI detection but is limited by its interpretation by inexperienced medical staff. To facilitate interpretation, an automated BSM algorithm was developed and is evaluated in this study. One hundred three patients with ischemic-type chest pain were recruited for this study from December 2001 to April 2002. A 12-lead electrocardiogram (Marquette Mac 5K) and BSM (PRIME-ECG) were recorded at initial presentation, and cardiac troponin I and/or creatine kinase-MB levels measured at 12 hours after symptom onset. The admitting physician's 12-lead electrocardiographic (ECG) interpretation, 12-lead ECG algorithm (Marquette 12 SL V233) diagnosis, and BSM algorithm diagnosis were documented for each patient. AMI, defined by elevation of troponin I to >1 microg/L and/or creatine kinase-MB to >25U/L, occurred in 53 patients. The admitting physician diagnosed 24 patients with AMI (sensitivity 45%, specificity 94%), the 12-lead ECG algorithm diagnosed 17 patients with AMI (sensitivity 32%, specificity 98%), and the BSM algorithm diagnosed 34 patients with AMI (sensitivity 64%, specificity 94%). The BSM algorithm improved the diagnostic sensitivity by 2.0 (p <0.001) and 1.4 (p = 0.002) compared with the 12-lead ECG algorithm or the admitting physician, respectively. There was no significant difference in specificity. Thus, the BSM algorithm improves detection of AMI compared with the 12-lead ECG algorithm or physician's 12-lead ECG interpretation.

Efficacy and safety of tenecteplase in combination with the low-molecular-weight heparin enoxaparin or unfractionated heparin in the prehospital setting: the Assessment of the Safety and Efficacy of a New Thrombolytic Regimen (ASSENT)-3 PLUS randomized trial in acute myocardial infarction

BACKGROUND

The combination of a single-bolus fibrinolytic and a low-molecular-weight heparin may facilitate prehospital reperfusion and further improve clinical outcome in patients with ST-elevation myocardial infarction.

METHODS AND RESULTS

In the prehospital setting, 1639 patients with ST-elevation myocardial infarction were randomly assigned to treatment with tenecteplase and either (1) intravenous bolus of 30 mg enoxaparin (ENOX) followed by 1 mg/kg subcutaneously BID for a maximum of 7 days or (2) weight-adjusted unfractionated heparin (UFH) for 48 hours. The median treatment delay was 115 minutes after symptom onset (53% within 2 hours). ENOX tended to reduce the composite of 30-day mortality or in-hospital reinfarction, or in-hospital refractory ischemia to 14.2% versus 17.4% for UFH (P=0.080), although there was no difference for this composite end point plus in-hospital intracranial hemorrhage or major bleeding (18.3% versus 20.3%, P=0.30). Correspondingly, there were reductions in in-hospital reinfarction (3.5% versus 5.8%, P=0.028) and refractory ischemia (4.4% versus 6.5%, P=0.067) but increases in total stroke (2.9% versus 1.3%, P=0.026) and intracranial hemorrhage (2.20% versus 0.97%, P=0.047). The increase in intracranial hemorrhage was seen in patients >75 years of age.

CONCLUSIONS

Prehospital fibrinolysis allows 53% of patients to receive reperfusion treatment within 2 hours after symptom onset. The combination of tenecteplase with ENOX reduces early ischemic events, but lower doses of ENOX need to be tested in elderly patients. At present, therefore, tenecteplase and UFH are recommended as the routine pharmacological reperfusion treatment in the prehospital setting.

Prediction of Recurrent Events by D-Dimer and Inflammatory Markers in Patients with Normal Cardiac Troponin I (PREDICT) Study

BACKGROUND

The independent predictive value of d-dimer and inflammatory markers for the risk of recurrent adverse events in patients with acute chest pain but normal levels of cardiac troponin I (cTnI) remains unclear.

METHODS

We studied 391 patients admitted to the hospital in 1 year with acute ischemic-type chest pain. Creatine kinase-myocardial band isoenzyme (CK-MB) mass and cTnI levels were measured in initial and 12-hour samples. Soluble intercellular adhesion molecule (sICAM)-1, vascular cell adhesion molecule (sVCAM)-1, sP-selectin, sE-selectin, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6), fibrinogen, and d-dimer levels were measured in initial samples. A 1-year incidence of death, myocardial infarction (MI), revascularization, or readmission with chest pain was determined (with death/MI as the primary end point).

RESULTS

Patients with normal levels of CK-MB(mass) and cTnI (195/391[50%]) were at a lower risk than patients with elevated levels of CK-MB(mass) or cTnI, but still had an important incidence of events (77/195[39%]). Marker elevation was defined as >75th percentile (upper quartile). Elevated d-dimer levels (>580 ng/mL) was predictive of death/MI (odds ratio, 5.4; 95% CI, 1.5-20.2; P =.005). Elevated sP-selectin levels (>152 ng/mL; odds ratio, 3.2; 95% CI, 0.9-11.6; P =.06) trended to increased death/MI rates, with weaker trends for elevated levels of hsCRP (>7.1 mg/L), IL6 (>10.7 pg/mL), and ST depression. Other markers, other electrocardiogram changes, or classic risk factors were not predictive of death/MI. With a multivariate analysis, d-dimer and sP-selectin were found to be of independent significance for death/MI after adjustment for inflammatory, hemostatic, and electrocardiogram markers and d-dimer after adjustment for classic risk factors.

CONCLUSION

Normal cTnI levels after acute chest pain does not confer absence of future risk. Concurrent assessment of d-dimer and inflammatory markers may improve risk stratification.

Impact of pre-hospital care in patients with acute myocardial infarction compared with those first managed in-hospital

AIMS

To compare prospectively the impact of pre-hospital care by a physician-staffed mobile coronary care unit with patients managed initially in-hospital, all with acute myocardial infarction.

METHODS AND RESULTS

This was a single centre registry of consecutive patients (n=750) admitted with acute myocardial infarction to the coronary care unit and cardiology wards of the Royal Victoria Hospital, Belfast between 1998 and 2001. For the 750 patients, in-hospital mortality was 11% and was significantly lower for those managed pre-hospital (8% vs 13%, P=0.04): patients who received fibrinolytic therapy (n=474), the in-hospital mortality was significantly lower in the pre-hospital group (7% vs 13%, P=0.02). Those managed pre-hospital had significant reduction in the median delay times (25th, 75th percentiles) from onset of symptoms to call for help 1.0 (0.5, 2.2) vs 2.0 (0.9, 6.0) h, P<0.001, from call for help to receiving fibrinolytic therapy 1.0 (0.8, 1.5) vs 1.8 (1.2, 2.5) h, P<0.001 resulting in a shorter pain-to-needle time for fibrinolytic therapy 2.3 (1.5, 3.8) vs 4.0 (2.6, 7.2) h, P<0.001. For all patients, older age, haemodynamic indicators on admission (hypotension, higher heart rate, heart failure) and managed by the in-hospital route were significant independent variables for an adverse in-hospital mortality. Although for patients aged >or=75 years no statistical significant reduction in mortality occurred for those managed pre-hospital (P=0.051), nevertheless patients in this age group first treated pre-hospital who received fibrinolytic therapy had a significantly lower mortality than those first treated in-hospital (21% vs 43%, P=0.02).

CONCLUSIONS

Consecutive patients with acute myocardial infarction seen and managed initially out-of-hospital by a physician-staffed mobile coronary care unit had significantly lower in-hospital mortality.

A multicenter study of the tolerability of tirofiban versus placebo in patients undergoing planned intracoronary stent placement

BACKGROUND

The use of intravenous glycoprotein IIb/IIIa-receptor antagonists has been shown to improve outcomes in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). Tirofiban has shown benefit in a wide range of patients presenting with acute coronary syndromes. Although this agent has been used in patients undergoing percutaneous coronary intervention, a literature search identified no prospective data comparing tirofiban with placebo in patients undergoing planned intracoronary stent placement.

OBJECTIVE

This study examined the tolerability of tirofiban in patients undergoing percutaneous intervention with planned intracoronary stent placement.

METHODS

This was a multinational, multicenter, prospective, randomized, double-blind, placebo-controlled trial in patients scheduled to undergo PTCA with planned intracoronary stent placement. Patients were randomized in a 3:2 ratio to receive tirofiban as an intravenous bolus (10 microg/kg over 3 minutes) and maintenance infusion (0.10 microg/kg per minute for 36 hours) or a bolus and infusion of placebo. All patients received periprocedural aspirin and heparin and an optional postprocedural thienopyridine (ticlopidine or clopidogrel). Laboratory and safety monitoring were performed throughout the 36 hours after the procedure and at hour 40 or hospital discharge. The primary end point was the proportion of patients with bleeding, defined according to Thrombolysis in Myocardial Infarction (TIMI) trial criteria. The number of patients with cardiac events (death, myo- cardial infarction, urgent revascularization) during the first 30 days after stent placement was also assessed.

RESULTS

Eight hundred ninety-four patients (536 tirofiban, 358 placebo) were enrolled, all of whom received aspirin and heparin periprocedurally and optional ticlopidine or clopidogrel after the procedure. No significant between-group differences were observed in the incidence of TIMI major bleeding (0.2% tirofiban, 0.6% placebo) or any TIMI bleeding (3.2% and 1.7%, respectively). The incidence of TIMI minor bleeding was higher with tirofiban than with placebo (2.8% vs 0.6%). The 30-day incidence of the composite end point of any cardiac event was 3.9% in both groups.

CONCLUSIONS

On a background of concomitant aspirin, heparin, and a thienopyridine, tirofiban was generally well tolerated in patients undergoing PTCA with planned intracoronary stent placement. Further investigation is needed to ascertain the optimal dosing of tirofiban and heparin to achieve reductions in ischemic complications of intracoronary stenting with an acceptable incidence of bleeding complications.

Optimization of transthoracic ventricular defibrillation-biphasic and triphasic shocks, waveform rounding, and synchronized shock delivery

The aim of this study is to optimize the truncated exponential waveform for transthoracic ventricular defibrillation. Discharge of a capacitor gives a fast-rising waveform with a spike; rounding of the waveform slows the rate of rise and removes the spike. Defibrillation thresholds for electrically induced VF were determined for rounded and conventional biphasic and triphasic waveforms (apex-anterior paddles; 130 microF capacitor; 3-10 ms phase duration), and for the Lown waveform in 29 anesthetized pigs. Rounding of the leading edge of the biphasic waveform reduced the threshold voltage and current for defibrillation at 3 + 3 ms and 6 + 6 ms phase duration, relative to the conventional unrounded biphasic or the Lown waveforms. The threshold delivered energy was lower for rounded truncated exponential biphasic shocks at 3 + 3 ms (55.3 +/- 2.5 J) than at 6 + 6 ms (67.6 +/- 2.9 J; reduction 15.9 +/- 3.8%; P <.001; n = 29) phase duration. Triphasic shocks (total duration 6-12 ms) showed no advantages over biphasic shocks in this model. The rounded waveform (6 + 6 ms phase duration) had a reduced delivered energy at threshold (9%) with transthoracic shock delivery synchronized to peak (71.1 +/- 4.2 J) or trough (71.5 +/- 4.9 J) of the high amplitude body surface electrocardiogram signal in ventricular fibrillation, compared with unsynchronized shocks (78.7 +/- 4.7 J; P <.05). In this study a biphasic, rounded waveform of total duration 6 or 12 ms, was optimal for the correction of electrically-induced ventricular fibrillation. Synchronization to the peak or trough of the high amplitude electrocardiogram signal gave a further reduction in the energy to defibrillate.

Resuscitation in the past, the present and the future

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Usefulness of the presenting electrocardiogram in predicting myocardial salvage with thrombolytic therapy in patients with a first acute myocardial infarction

AIMS

Patients with Q waves and T-wave inversion are generally at a later stage of the infarction process than patients without these changes. Our aim was to investigate whether a single assessment of electrocardiographic parameters at presentation would predict the proportion of myocardium salvageable by thrombolytic therapy.

METHODS AND RESULTS

Electrocardiographic algorithms to calculate the potential and final infarct size have been developed and allow the proportion of myocardium salvageable with therapy to be calculated. This was measured in 146 patients with acute myocardial infarction who had angiography at a median of 91 min after streptokinase. The relationship between myocardial salvage and the electrocardiographic parameters at presentation (Q waves, T-wave inversion, quantitative ST segment changes, and the initial QRS score), was examined together with the 90-min angiographic parameters (TIMI flow grade and collateral grade), clinical parameters (haemodynamics and age), and time to therapy. Parameters that correlated with myocardial salvage included the initial QRS score (r=-0.56, P<0.0001), Q wave grade (r=-0.36, P<0.0001), number of leads with ST depression (r=0.28, P<0.001), maximum ST depression (r=0.27, P<0.01), T-inversion grade (r=-0.26, P<0.01), and TIMI flow grade at 90 min (r=0.21, P<0.02). The time from symptom onset to thrombolytic therapy did not correlate with salvage (r=-0.09). On multivariate analysis, only the initial QRS score and T-inversion grade on the initial electrocardiogram were independent predictors of salvage (multivariate r using both variables combined=0.57, P<0.001).

CONCLUSIONS

The QRS score and T-wave inversion grade on the presenting electrocardiogram provide important information in predicting myocardial salvage. These parameters may help triage patients to appropriate therapies.

Eptifibatide and low-dose tissue plasminogen activator in acute myocardial infarction: the integrilin and low-dose thrombolysis in acute myocardial infarction (INTRO AMI) trial

OBJECTIVES

This study was designed to test the hypothesis that eptifibatide and reduced-dose tissue plasminogen activator (t-PA) will enhance infarct artery patency at 60 min in patients with acute myocardial infarction (AMI).

BACKGROUND

Combination fibrin and platelet lysis improves epicardial and myocardial reperfusion in AMI.

METHODS

Patients were enrolled in a dose finding (Phase A, n = 344) followed by a dose confirmation (Phase B, n = 305) protocol. All patients received aspirin and weight-adjusted heparin and underwent angiography at 60 and 90 min. In Phase A, eptifibatide in a single or double bolus (30 min apart) of 180, 180/90 or 180/180 microg/kg followed by an infusion of 1.33 or 2.0 microg/kg per min was sequentially added to 25 or 50 mg of t-PA. In Phase B, patients were randomized to: 1) double-bolus eptifibatide 180/90 (30 min apart) and 1.33 microg/kg per min infusion with 50 mg t-PA (Group I); 2) 180/90 (10 min apart) and 2.0 g/kg per min with 50 mg t-PA (Group II); or 3) full-dose, weight-adjusted t-PA (Group III).

RESULTS

In Phase A, the best rate of Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 was achieved using 180/90/1.33 microg/kg per min eptifibatide with 50 mg t-PA: 65% and 78% at 60 and 90 min, respectively. In Phase B, the incidence of TIMI flow grade 3 at 60 min was 42%, 56% and 40%, for Groups I through III, respectively (p = 0.04, Group II vs. Group III). The median corrected TIMI frame count was 38, 33 and 50, respectively (p = 0.02). TIMI major bleeding was reported in 8%, 11% and 6%, respectively; intracranial hemorrhage occurred in 1%, 3% and 2% of patients (p > 0.5 for both). The incidences of death (4%, 5% and 7%), reinfarction or revascularization at 30 days were similar among the three treatment groups.

CONCLUSIONS

In comparison with standard t-PA regimen, double-bolus eptifibatide (10 min apart) with a 48-h infusion and half-dose t-PA (Group II) is associated with improved quality and speed of reperfusion. The safety profile of this therapy is similar to that of other combination regimens.

Current management of unstable angina: lessons from the TACTICS-TIMI 18 trial

Patients presenting with unstable angina pectoris or non-Q-wave myocardial infarction (MI), if treated inadequately, are at a high risk of MI and subsequent mortality. The use of intravenous small molecule glycoprotein IIb/IIIa inhibitors along with standard therapeutic management options improves outcome. Since the publication of the Thrombolysis in Myocardial Ischemia IIIB, Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) and Fragmin and Fast Revascularization during InStability in Coronary artery disease II (FRISC II) studies, there is great debate about the advantages of following an early 'invasive' treatment option with coronary angiography and revascularization after initial medical therapy compared with the 'conservative' approach, where angiography is reserved for those who remain symptomatic. The Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy--Thrombolysis in Myocardial Infarction 18 (TACTICS-TIMI 18) study has helped to resolve some of the controversies since it was designed with more current medical (early and routine use of tirofiban) and revascularization (use of stents during percutaneous coronary interventions) options as part of the invasive treatment protocol. This study indicated that an early invasive strategy in risk stratified patients combined with early use of tirofiban with standard medical therapy significantly improves outcome and appears well tolerated.