Biomedical subjects

Jennifer Adgey

Publications and source records attributed to Jennifer Adgey.

8 recordsLinked to original sources

PubMed2006

Prehospital fibrinolysis with dual antiplatelet therapy in ST-elevation acute myocardial infarction: a substudy of the randomized double blind CLARITY-TIMI 28 trial.

BACKGROUND: Fibrinolytic therapy for acute ST-elevation myocardial infarction (STEMI) is frequently limited by delays in administration and by incomplete reperfusion or reocclusion of the infarct-related artery. Intensified prehospital management of STEMI may shorten time to treatment and improve outcomes. METHODS: We carried out a prospective substudy in 11 ambulance systems in 216 of the 3,491 patients with STEMI who were enrolled in the CLARITY-TIMI 28 trial. They were randomized in the ambulance to clopidogrel (n = 109) or placebo (n = 107) along with fibrinolysis, aspirin, and heparin. The primary endpoint was the composite of an occluded infarct-related artery (TIMI flow grade 0 or 1), or death or recurrent myocardial infarction before angiography. RESULTS: All patients received a fibrin-specific lytic and the baseline characteristics in both groups were comparable. The incidence of the primary endpoint was 16.5% in the clopidogrel-treated and 27.1% in the placebo patients (adj OR 0.62, 95% CI 0.31-1.21, p = 0.16), an effect that was consistent with the effects seen in the in-hospital patients in the main CLARITY-TIMI 28 trial. Prehospital clopidogrel therapy reduced the incidence of an occluded infarct-related artery on the predischarge angiogram (11.8% vs. 22.3%, adj OR 0.52, 95% CI 0.24-1.13, p = 0.10). The 30-day incidence of cardiovascular death, recurrent MI or recurrent myocardial ischemia requiring urgent revascularization was 12.8% vs. 14.0% (adj OR 1.07, 95% CI 0.48-2.39, p = 0.87). Early TIMI major bleeding occurred in no clopidogrel patients compared with two placebo patients (1.9%). CONCLUSIONS: Addition of clopidogrel to medical reperfusion of STEMI with fibrinolysis, heparin, and aspirin before reaching the hospital is feasible in medically equipped ambulances without an apparent increase in bleeding. Furthermore, prehospital clopidogrel tended to show better early coronary patency compared to placebo, a result consistent with that observed in patients randomized in-hospital in the CLARITY-TIMI 28 trial.

Aged↗

PubMed2006

Age, outcomes, and treatment effects of fibrinolytic and antithrombotic combinations: findings from Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT)-3 and ASSENT-3 PLUS.

BACKGROUND: Elderly patients with acute myocardial infarction are at particularly high risk for death and bleeding complications. The efficacy and safety of antithrombotic strategies in these patients remain unclear. METHODS: To provide more insight into the risk and benefit of antithrombotic strategies in the elderly, we examined patients from the ASSENT-3 and ASSENT-3 PLUS trials with STEMI who were treated with tenecteplase (TNK) and unfractionated heparin (UFH) or enoxaparin, or half-dose TNK with abciximab and reduced-dose UFH. RESULTS: Older patients had a higher risk profile, and lower use of concomitant therapies and revascularization procedures. We found an interaction between age and treatment effect for the efficacy end point (P = .0007) and the efficacy plus safety end point (P < .0001). Younger patients (<65 years) had a lower risk of the composite efficacy plus safety end point with enoxaparin (relative risk [RR] 0.84, 95% CI 0.74-0.94) or abciximab (RR 0.79, 95% CI 0.69-0.90) compared with UFH. In patients >65 years of age, the benefit of enoxaparin appeared to be offset by an increased risk of bleeding complications. The risk of the efficacy plus safety end point tended to be higher in elderly patients receiving abciximab and half-dose TNK (RR 1.18, 95% CI 0.91-1.51 for 76-85 years of age and RR 1.48, 95% CI 0.88-2.49 for >85 years of age). CONCLUSIONS: Although TNK with either enoxaparin or abciximab appeared to be more effective than with standard UHF in younger patients, these combinations tended to be less effective and even may be unsafe in the elderly. Development of new combination strategies and dosing schemes of fibrinolytics and antithrombotics with improved efficacy and safety in the elderly remains a high priority.

Aged↗

PubMed2005

Improved detection of acute myocardial infarction using a diagnostic algorithm based on calculated epicardial potentials.

BACKGROUND: New methods for detecting myocardial infarction in patients with suspected acute coronary syndromes are needed particularly in an era where the majority of patients with myocardial infarction present with non-diagnostic 12-lead electrocardiograms (ECG). We compared a novel epicardial diagnostic algorithm using epicardial potentials from the 80-lead body surface map with other electrocardiographic techniques in detection of myocardial infarction. METHODS: Between February 1999 and February 2001, consecutive patients (n=427) with ischemic type chest pain had an initial 12-lead ECG and body surface map recorded. Detecting myocardial infarction using an epicardial algorithm was first performed in a training set (n=213) and tested in a validation set of patients (n=214). The results from this epicardial algorithm in myocardial infarction detection were compared with the physician's interpretation of the 12-lead ECG, the body surface map algorithm (PRIME) and physician's interpretation of the body surface map. RESULTS: Myocardial infarction occurred in 205 patients (creatine kinase >or=2x upper limit of normal with creatine kinase-MB >or=7% CK). The physician's interpretation of the 12-lead ECG identified 122 with myocardial infarction (sensitivity 60%, specificity 99%), the body surface map algorithm 137 (sensitivity 67%, specificity 89%), the physician's interpretation of the body surface map 153 (sensitivity 75%, specificity 91%) and the epicardial algorithm 158 (sensitivity 77% specificity 99%). Combining the physician's interpretation of the 12-lead ECG with the epicardial algorithm increased significantly the detection of myocardial infarction (sensitivity 85%, specificity 98%, p<0.001) compared with the 12-lead ECG. CONCLUSIONS: An epicardial algorithm based on epicardial potentials increases significantly the detection of myocardial infarction particularly among those with non-diagnostic 12-lead ECG's.

Aged↗

PubMed2004

Comparing the efficacy and safety of a novel monophasic waveform delivered by the passive implantable atrial defibrillator with biphasic waveforms in cardioversion of atrial fibrillation.

BACKGROUND: The passive implantable atrial defibrillator (PIAD) (with no battery or discharging capacitor and powered transcutaneously by radio-frequency energy) delivering a novel monophasic low-tilt waveform is more efficacious than the standard monophasic waveform at atrial defibrillation. Standard biphasic (STB) waveforms, however, are more efficacious and safer than monophasic waveforms. This study compared the efficacy and safety of the PIAD waveform with biphasic waveforms. METHODS AND RESULTS: Sustained atrial fibrillation (AF) was induced by rapid atrial pacing. Cardioversion was attempted via 2 atrial defibrillation leads. The efficacy of the PIAD was compared with 3 biphasic waveforms (standard, single rounded, and double rounded) at varying voltage settings in 10 pigs. After a synchronized shock, hemodynamic changes between the PIAD, standard biphasic, and monophasic waveforms were compared at 1.5 and 3.0 J in 12 pigs. Myocardial injury (biochemical and histological) after ten 5-J PIAD shocks was compared with a no-shock group in 14 pigs. The PIAD 100-V setting was significantly more efficacious than the STB (100/-50 V: 100% [1.88+/-0.02 J] versus 90% [0.89+/-0.0 J]; P=0.025). No arrhythmic, hemodynamic, or myocardial injury was observed with the PIAD waveform. CONCLUSIONS: Defibrillation with the PIAD is more efficacious than with the STB waveform and appears safe. This device could provide a more effective option for cardioversion.

Animals↗

PubMed2004

Mortality following non-ST elevation acute coronary syndrome: 4 years follow-up of the PRAIS UK Registry (Prospective Registry of Acute Ischaemic Syndromes in the UK).

AIM: To present information on long-term prognosis and risk factors following an admission with non-ST elevation acute coronary syndrome. METHODS: A cohort of 653 patients was followed for mortality and causes of death using data from the UK Office of National Statistics (ONS). Cox proportional hazards model was used to identify the prognostic factors. RESULTS: Overall survival at a maximum follow-up of 45 months was 77.8% (95% CI 74.1-81.1%). Seventy-three per cent of the deaths were clearly due to a cardiovascular cause. Age, male gender, heart failure, ST depression or bundle branch block were all associated with higher short- and long-term risk. Taking aspirin or having a revascularization procedure, over the period of six months following initial hospitalisation were both associated with a lower long-term risk. CONCLUSION: Non-ST elevation acute coronary syndromes carry a high risk of death over a 4-year period. Conventional risk factors can predict both short- and long-term risk. More invasive management and the use of evidence-based therapies appear to be associated with a lower risk.

Adult↗

PubMed2004

Variations in pre-hospital fibrinolysis process of care: insights from the Assessment of the Safety and Efficacy of a New Thrombolytic 3 Plus international acute myocardial infarction pre-hospital care survey.

The Assessment of the Safety and Efficacy of a New Thrombolytic 3 (ASSENT 3 PLUS) Plus trial (n=1639) was an international trial of pre-hospital fibrinolysis with tenecteplase randomly assigned to enoxaparin or unfractionated heparin, involving 106 sites in 12 countries. Given the potential impact of process of care delivery in various healthcare systems, we undertook a comprehensive validated survey of population demographics, geographical factors, emergency medical services, methods of electrocardiogram interpretation and pre-hospital fibrinolysis administration. The potential study population was 42.4 x 10(6) with 70% urban. The land areas of individual emergency medical services sites varied from 6 to 20000/km(2). Three emergency medical services personnel (range 2-5) attended each ambulance with the highest level of training, consisting of a physician (65%), registered nurse (20%) or paramedic. Before the initiation of the study, 72% of sites administered pre-hospital fibrinolysis (range 1-20 years). Electrocardiograms were interpreted on the scene in 60% and transmitted for physician's interpretation in the remainder; 41% of patients (679/1639) were enrolled at sites without a physician at the scene. The ASSENT 3 Plus trial incorporated a wide variation in population density, emergency medical services resources, and physician's interpretation of ECG and administering pre-hospital fibrinolysis. Understanding this diversity will help in evaluating the general applicability and feasibility of pre-hospital fibrinolysis in various health systems, as well as the pre-hospital care of ST elevation myocardial infarction patients regardless of reperfusion strategies.

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PubMed2003

Novel passive implantable atrial defibrillator using transcutaneous radiofrequency energy transmission successfully cardioverts atrial fibrillation.

BACKGROUND: Conventional methods for cardioversion of atrial fibrillation (AF) to sinus rhythm have numerous difficulties. A novel method for cardioversion using the passive implantable atrial defibrillator (PIAD) was tested in acute animal models. This device does not have a battery or a capacitor to store energy and is activated by transferring RF energy across the skin from an external transmitter to the subcutaneously implanted defibrillator. On activation, a novel monophasic shock waveform with 5% tilt is delivered to the heart via 2 intracardiac defibrillation leads. METHODS AND RESULTS: Cardioversion attempts with the device were assessed in 2 phases: a feasibility and efficacy study and randomized comparison against standard waveforms. Defibrillation leads were placed transvenously into the distal coronary sinus and the right atrial appendage. These were connected to the subcutaneously implanted PIAD. Sustained AF was induced by rapid atrial pacing. The transmitter coil was placed on the skin overlying the defibrillator, and defibrillation synchronized to the R wave was attempted. The method was found to be efficacious at very low voltage and energy, with 100% cardioversion success observed for 10-ms 100-V shocks (mean energy, 1.54+/-0.02 J). The PIAD waveform had a higher cardioversion success rate than a truncated, 70% tilt monophasic exponential pulse (100 V, 100% versus 78.0+/-7.57%; P=0.001). There were no postshock complications. CONCLUSIONS: Considering these animal results, this method is promising for cardioverting AF in symptomatic patients.

Animals↗

PubMed2003

The use of calculated epicardial potentials improves significantly the sensitivity of a diagnostic algorithm in the detection of acute myocardial infarction.

Inverse electrocardiography can calculate epicardial potentials (EP) from body surface potentials (BSP) taking into account a thoracic volume conductor model (TVCM). Previous studies have shown that a tailored TVCM is superior to a general TVCM in calculating EP. However, construction of a tailored TVCM for a patient in an acute clinical setting is impractical. In this study we used a general TVCM in our EP calculations to determine whether this improves detection of acute myocardial infarction (AMI) using a diagnostic algorithm. BSP were derived from the 80-lead body surface map (BSM). Consecutive patients (n=379) with ischemic type chest pain were recruited. The BSM and a 12-lead electrocardiogram (ECG) were recorded at initial presentation and creatine kinase (CK) and/or CK-MB were measured initially, 12 and 24 hours postsymptom onset. A physician interpreted the 12-lead electrocardiogram and documented ST elevation if present. AMI was defined by the World Health Organization (WHO) criteria. The diagnostic algorithm result for each patient using BSP and calculated EP were documented. AMI occurred in 171 patients. The diagnostic algorithm using BSP identified 106 of these as ST elevation AMI (STEMI) (sensitivity 62%, specificity 80%). The same algorithm using EP identified 133 as STEMI (sensitivity 78%, specificity 80%). Calculated EP improved the algorithm's diagnostic sensitivity by a factor of 1.25 (P<.001) with no significant difference in specificity. Calculated EP using a general TVCM significantly improves the sensitivity of a diagnostic algorithm based on BSP in detection of AMI with no significant loss in specificity.

Algorithms↗