Cardiac procedures in ST-segment-elevation myocardial infarction - the influence of age, geography and Aboriginality.

BACKGROUND: Timely restoration of bloodflow acute ST-segment elevation myocardial infarction (STEMI) reduces myocardial damage and improves prognosis. The objective of this study was describe the association of demographic factors with hospitalisation rates for STEMI and time to angiography, Percutaneous Coronary Intervention (PCI) and Coronary Artery Bypass Graft (CABG) in New South Wales (NSW) and the Australian Capital Territory (ACT), Australia. METHODS: This was an observational cohort study using linked population health data. We used linked records of NSW and the ACT hospitalisations and the Australian Government Medicare Benefits Schedule (MBS) for persons aged 35 and over hospitalised with STEMI in the period 1 July 2010 to 30 June 2014. Survival analysis was used to determine the time between STEMI admission and angiography, PCI and CABG, with a competing risk of death without cardiac procedure. RESULTS: Of 13,117 STEMI hospitalisations, 71% were among males; 55% were 65-plus years; 64% lived in major cities, and 2.6% were Aboriginal people. STEMI hospitalisation occurred at a younger age in males than females. Angiography and PCI rates decreased with age: angiography 69% vs 42% and PCI 60% vs 34% on day 0 for ages 35-44 and 75-plus respectively. Lower angiography and PCI rates and higher CABG rates were observed outside major cities. Aboriginal people with STEMI were younger and more likely to live outside a major city. Angiography, PCI and CABG rates were similar for Aboriginal and non-Aboriginal people of the same age and remoteness area. CONCLUSIONS: There is a need to improve access to definitive revascularisation for STEMI among appropriately selected older patients and in regional areas. Aboriginal people with STEMI, as a population, are disproportionately affected by access to definitive revascularisation outside major cities. Improving access to timely definitive revascularisation in regional areas may assist in closing the gap in cardiovascular outcomes between Aboriginal and non-Aboriginal people.

The Mental Health Acute Assessment Team: a collaborative approach to treating mental health patients in the community.

OBJECTIVE: Many models of community-based mental health crisis teams have been reported. We present our experience of an outreach team made up of a paramedic and mental health nurse. METHODS: A proof-of-concept was conducted in Western Sydney. The primary outcome was the proportion of patients where the team were able to facilitate the most appropriate care. RESULTS: Nearly 70% of patients were able to be treated outside the Emergency Department, with about two-thirds being transported directly to a mental health facility. CONCLUSION: We have demonstrated that our model of care is successful in enabling appropriate physical and mental health care for patients suffering an acute mental health crisis.

Biphasic versus monophasic waveforms for transthoracic defibrillation in out-of-hospital cardiac arrest.

BACKGROUND: Transthoracic defibrillation is a potentially life-saving treatment for people with ventricular fibrillation (VF) and haemodynamically unstable ventricular tachycardia (VT). In recent years, biphasic waveforms have become more commonly used for defibrillation than monophasic waveforms. Clinical trials of internal defibrillation and transthoracic defibrillation of short-duration arrhythmias of up to 30 seconds have demonstrated the superiority of biphasic waveforms over monophasic waveforms. However, out-of-hospital cardiac arrest (OHCA) involves a duration of VF/VT of several minutes before defibrillation is attempted. OBJECTIVES: To determine the efficacy and safety of biphasic defibrillation waveforms, compared to monophasic, for resuscitation of people experiencing out-of-hospital cardiac arrest. SEARCH METHODS: We searched the following electronic databases for potentially relevant studies up to 10 September 2014: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Also we checked the bibliographies of relevant studies and review articles, contacted authors of published reviews and reviewed webpages (including those of device manufacturers) relevant to the review topic. We handsearched the abstracts of conference proceedings for the American Heart Association, American College of Cardiology, European Society of Cardiology, European Resuscitation Council, Society of Critical Care Medicine and European Society of Intensive Care Medicine. Regarding language restrictions, we did not apply any. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared biphasic and monophasic waveform defibrillation in adults with OHCA. Two review authors independently screened the literature search results. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from the included trials and performed 'Risk of bias' assessments. We resolved any disagreements by discussion and consensus. The primary outcome was the risk of failure to achieve return of spontaneous circulation (ROSC). Secondary outcomes included risk of failure to revert VF to an organised rhythm following the first shock or up to three shocks, survival to hospital admission and survival to discharge. MAIN RESULTS: We included four trials (552 participants) that compared biphasic and monophasic waveform defibrillation in people with OHCA. Based on the assessment of five quality domains, we identified two trials that were at high risk of bias, one trial at unclear risk of bias and one trial at low risk of bias. The risk ratio (RR) for failure to achieve ROSC after biphasic compared to monophasic waveform defibrillation was 0.86 (95% CI 0.62 to 1.20; four trials, 552 participants). The RR for failure to defibrillate on the first shock following biphasic defibrillation compared to monophasic was 0.84 (95% CI 0.70 to 1.01; three trials, 450 participants); and 0.81 (95% CI 0.61 to 1.09; two trials, 317 participants) for one to three stacked shocks. The RR for failure to achieve ROSC after the first shock was 0.92 (95% CI 0.81 to 1.04; two trials, 285 participants). Biphasic waveforms did not reduce the risk of death before hospital admission (RR 1.05, 95% CI 0.90 to 1.23; three trials, 383 participants) or before hospital discharge (RR 1.05, 95% CI 0.78 to 1.42; four trials, 550 participants). There was no statistically significant heterogeneity in any of the pooled analyses. None of the included trials reported adverse events. AUTHORS' CONCLUSIONS: It is uncertain whether biphasic defibrillators have an important effect on defibrillation success in people with OHCA. Further large studies are needed to provide adequate statistical power.

Late Outcomes of Patients With Prehospital ST-Segment Elevation and Appropriate Cardiac Catheterization Laboratory Nonactivation.

Background Patients with suspected ST-segment-elevation myocardial infarction (STEMI) and cardiac catheterization laboratory nonactivation (CCL-NA) or cancellation have reportedly similar crude and higher adjusted risks of death compared with those with CCL activation, though reasons for these poor outcomes are not clear. We determined late clinical outcomes among patients with prehospital ECG STEMI criteria who had CCL-NA compared with those who had CCL activation. Methods and Results We identified consecutive prehospital ECG transmissions between June 2, 2010 to October 6, 2016. Diagnoses according to the Fourth Universal Definition of myocardial infarction (MI), particularly rates of myocardial injury, were adjudicated. The primary outcome was all-cause death. Secondary outcomes included cardiovascular death/MI/stroke and noncardiovascular death. To explore competing risks, cause-specific hazard ratios (HRs) were obtained. Among 1033 included ECG transmissions, there were 569 (55%) CCL activations and 464 (45%) CCL-NAs (1.8% were inappropriate CCL-NAs). In the CCL activation group, adjudicated index diagnoses included MI (n=534, 94%, of which 99.6% were STEMI and 0.4% non-STEMI), acute myocardial injury (n=15, 2.6%), and chronic myocardial injury (n=6, 1.1%). In the CCL-NA group, diagnoses included MI (n=173, 37%, of which 61% were non-STEMI and 39% STEMI), chronic myocardial injury (n=107, 23%), and acute myocardial injury (n=47, 10%). At 2 years, the risk of all-cause death was higher in patients who had CCL-NA compared with CCL activation (23% versus 7.9%, adjusted risk ratio, 1.58, 95% CI, 1.24-2.00), primarily because of an excess in noncardiovascular deaths (adjusted HR, 3.56, 95% CI, 2.07-6.13). There was no significant difference in the adjusted risk for cardiovascular death/MI/stroke between the 2 groups (HR, 1.23, 95% CI, 0.87-1.73). Conclusions CCL-NA was not primarily attributable to missed STEMI, but attributable to "masquerading" with high rates of non-STEMI and myocardial injury. These patients had worse late outcomes than patients who had CCL activation, mainly because of higher rates of noncardiovascular deaths.

Reconfirmation algorithms should be the standard of care in automated external defibrillators.

Non-sustained and self-terminating arrhythmias pose a significant challenge during resuscitation. Delivery of a defibrillation shock to a non-shockable rhythm has a poorly understood effect on the heart. The importance of assessing rhythm right up until the delivery of a shock is of increased importance when "blind" shocks are being delivered by automatic defibrillators or minimally trained rescuers. Reconfirmation algorithms are common in current-generation implantable defibrillators but this investigation of current-generation AEDs shows that only 71% of devices presently available have reconfirmation algorithms. A case of spontaneous reversion of a non-sustained arrhythmia is presented. The implications of delivering a defibrillator shock to a non-shockable rhythm are discussed.

Towards new models of cardiopulmonary resuscitation teaching: the role of practical scenario training on surf lifesavers' perceptions of resuscitation efficacy.

INTRODUCTION: Surf lifesavers in Australia undertake numerous resuscitation scenarios in the course of their training and examination. The standard teaching and examination strategy is for the scenario to end with return of spontaneous circulation (ROSC) and then breathing. This study was performed to assess the effect of this training technique on lifesavers' expectation of successful resuscitation and to determine the effect of experience on these expectations. METHODS: Participants were lifesavers from Surf Life Saving Sydney Northern Beaches (SLSSNB). Data was collected by questionnaire. Questionnaires were applied to newly qualified lifesavers, a random sample of patrolling lifesavers and a strategic group of lifesavers with extensive experience in resuscitation. Anticipation of ROSC was recorded on a visual analogue scale (VAS). RESULTS: The mean VAS for the expected likelihood of successful resuscitation was 55.0+/-19.2% (95% CI: 51.3-58.6%). Published rates of ROSC range from 9 to 36.4%. Nearly 80% of our respondents expected better than 36.4% chance of ROSC. There was no difference in anticipation of ROSC between the three groups (F=0.41; 2,99df; P=0.67). Time since learning cardiopulmonary resuscitation (CPR) did not affect the expectancy of ROSC (F=0.92; 5,101df; P=0.47). Similarly, the number of resuscitations performed by an individual did not affect anticipation of successful outcome (F=0.13; 3,102df; P=0.94). CONCLUSIONS: Surf lifesavers in the Sydney Northern Beaches branch have an exaggerated expectation of the chances of successful CPR following cardiac arrest. This expectation did not change with time since learning CPR or participation in actual resuscitations. New models for CPR education need to be investigated.

Biphasic and monophasic shocks for transthoracic defibrillation: a meta analysis of randomised controlled trials.

INTRODUCTION: Biphasic waveforms are routinely used for implantable defibrillators. These waveforms have been less readily adopted for external defibrillation. This study was performed in order to evaluate the efficacy and harms of biphasic waveforms over monophasic waveforms for the transthoracic defibrillation of patients in ventricular fibrillation (VF) or haemodynamically unstable ventricular tachycardia. METHODS: Studies included randomised controlled trials comparing monophasic and biphasic external defibrillation for participants with VF or hemodynamically unstable ventricular tachycardia. Seven trials (1129 patients) were included in the analysis. All trials were conducted during electrophysiology procedures or implantable cardioverter/defibrillator testing. RESULTS: Compared with 200 J monophasic shocks, 200 J biphasic shocks reduced the risk of post-first shock asystole or persistent VF by 81% (relative risk (RR) 0.19; 95% confidence intervals (CI) 0.06-0.60) for the first shock. Reducing the energy of the biphasic waveform to 115-130 J resulted in similar effectiveness compared with the monophasic waveform at 200 J (RR 1.07, CI 0.66-1.74). Low energy biphasic shocks produce less myocardial injury than higher energy monophasic shocks as determined by ST segment deflection after shock. CONCLUSIONS: Biphasic waveforms defibrillate with similar efficacy at lower energies than standard 200 J monophasic waveforms, and greater efficacy than monophasic shocks of the same energy. Available data suggests that lower delivered energy and voltage result in less post-shock myocardial injury.

Exercise training in patients with stable chronic heart failure: effects on thoracic impedance cardiography and B-type natriuretic peptide.

PURPOSE: Recent evidence has suggested that patients with stable chronic heart failure (CHF) may respond favorably to a progressive exercise program. The use of noninvasive hemodynamic monitoring and B-type natriuretic peptide (BNP) measurement in these patients is not well reported. This study investigated the utility of noninvasive hemodynamic monitoring and point-of-care BNP in a cardiac rehabilitation outpatient setting. METHODS: Patients with stable CHF were assigned to a supervised 12-week exercise program (n = 13) or control (n = 6). At baseline and at the end of the study period, patients were assessed for functional and quality-of-life status. Point-of-care BNP and noninvasive hemodynamic parameters were also obtained. RESULTS: As expected, patients assigned to the exercise group showed significant improvement in quality of life and distance covered by the 6-minute walk test, but control subjects showed no such changes. There was a trend toward improved BNP in the exercise group, with 73% of these patients showing a decrease in comparison with 67% of controls showing an increase. There was a significant improvement in stroke volume in the exercise group but not in the control group. CONCLUSIONS: Both BNP and noninvasive hemodynamic monitoring can be utilized in the cardiac rehabilitation outpatient setting and seem to mirror the favorable response to exercise of other functional tests.