Introduction Supraventricular tachycardias (SVTs) are a common cause of acute hospital presentations. Adenosine is an effective treatment. To date, no studies have directly compared paramedic-with hospital-delivered treatment of acute SVT with adenosine. Method Randomised controlled trial comparing the treatment of SVT and discharge by paramedics with conventional emergency department (ED)-based care. Patients were excluded if they had structural heart disease or contraindication to adenosine. Discharge time, follow-up management, costs and patient satisfaction were compared. Results Eighty-six patients were enrolled: 44 were randomised to paramedic-delivered adenosine (PARA) and 42 to conventional care (ED). Of the 37 patients in the PARA group given adenosine, the tachycardia was successfully terminated in 81%. There was a 98% correlation between the paramedics' ECG diagnosis and that of two electrophysiologists. No patients had any documented adverse events in either group. The discharge time was lower in the PARA group than in the ED group (125 min (range 55–9513) vs 222 min (range 72–26 153); p=0.01), and this treatment strategy was more cost-effective (£282 vs £423; p=0.01). The majority of patients preferred this management approach. Being treated and discharged by paramedics did not result in the patients being less likely to receive ongoing management of their arrhythmia and cardiology follow-up. Conclusions Patients with SVT can effectively and safely be treated with adenosine delivered by trained paramedics. Implementation of paramedic-delivered acute SVT care has the potential to reduce healthcare costs without compromising patient care. Trial registration number NCT02216240.

Objective To assess whether a novel ‘direct access pathway’ (DAP) for the management of high-risk non-ST-elevation acute coronary syndromes (NSTEACS) is safe, results in ‘shorter time to intervention and shorter admission times’. This pathway was developed locally to enable London Ambulance Service to rapidly transfer suspected high-risk NSTEACS from the community to our regional heart attack centre for consideration of early angiography. Methods This is a retrospective case–control analysis of 289 patients comparing patients with high-risk NSTEACS admitted via DAP with age-matched controls from the standard pan-London high-risk ACS pathway (PLP) and the conventional pathway (CP). The primary end point of the study was time from admission to coronary angiography/intervention. Secondary end point was total length of hospital stay. Results Over a period of 43 months, 101 patients were admitted by DAP, 109 matched patients by PLP and 79 matched patients through CP. Median times from admission to coronary angiography for DAP, PLP and CP were 2.8 (1.5–9), 16.6 (6–50) and 60 (33–116) hours, respectively (p<0.001). Median length of hospital stay for DAP and PLP was similar at 3.0 (2.0–5.0) days in comparison to 5 (3–7) days for CP (p<0.001). Conclusions DAP resulted in a significant reduction in time to angiography for patients with high-risk NSTEACS when compared to existing pathways.

Background Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated whether direct transfer to a cardiac centre performing primary percutaneous coronary intervention (PPCI) leads to improved survival compared with transfer via a non-PPCI performing hospital in STEMI patients in a regional network. Methods This was an observational cohort study of 10 108 patients with STEMI treated with PPCI between 2004 and 2011 at eight tertiary cardiac centres across London, UK. Patient9s details were recorded at the time of the procedure into the British Cardiac Intervention Society (BCIS) database. Outcome was assessed by all-cause mortality. Anonymous datasets from the eight centres were merged for analysis. The primary end-point was all-cause mortality at a median follow-up of 3.0 years (IQR range 1.2–4.6 years). Results 6492 patients (64.2%) were transferred directly to a PCI performing centre (direct) and 3616, (35.8%) were transferred via a non-PCI performing centre (indirect). There were higher rates of previous MI and previous CABG in the indirect group, with higher rates of poor LV function in the direct group (table 1). Median time to reperfusion (symptom to balloon) in transferred patients was 58 min longer compared to patients admitted directly (p<0.001). However, symptom to first hospital door times were similar. Transferred patients had significantly lower rates of infarct-related artery (IRA) TIMI 0 flow (54.5% vs 62.9%, p<0.0001) and higher rates of IRA TIMI 3 flow (17% vs 10.7%, p>0.0001) at presentation compared to those transferred directly. Kaplan-Meier analysis demonstrated no significant difference in mortality rates between patients with and without transfer (12.3% direct vs 14.3% indirect, p=0.060). Age-adjusted Cox analysis revealed inter-hospital transfer for PPCI was associated with all cause mortality (HR 0.89 (95% CI 0.79 to 0.99)), however this was not maintained after multivariate adjustment (HR 0.84 (95% CI 0.62 to 1.14)). Conclusions In this large registry survival appear comparable in patients with STEMI admitted directly versus transferred for primary PCI. This is despite longer symptom to balloon times. This unexpected finding may reflect the earlier initiation of medical therapy (eg, anti-platelets and GpIIb/IIIa receptor inhibitors) and earlier pharmacological reperfusion, reflected by lower IRA TIMI 0 rates at angiography in the patients transferred from a non-PCI hospital.

Background Limited information exists regarding procedural success and clinical outcomes of ST-segment elevation myocardial infarction (STEMI) in patients with previous CABG undergoing primary PCI. We sought to compare outcomes in STEMI patients undergoing primary percutaneous coronary intervention (PCI) with or without previous coronary artery bypass grafts (CABG). Methods This was an observational cohort study of 10,920 patients with STEMI who were treated with PPCI between 2004 and 2011 at eight tertiary cardiac centres across London, UK. Patient's details were recorded at the time of the procedure into the British Cardiac Intervention Society (BCIS) database. Outcome was assessed by all-cause mortality. Anonymous datasets from the eight centres were merged for analysis. The primary end-point was all-cause mortality at a mean follow-up of 3.0 years. Results 347 (3.2%) patients had previous CABG. Patients with previous CABG were older and had more associated comorbidities than patients who have never had CABG. In patients with previous CABG, the infarct related artery (IRA) was split evenly between a bypass graft and a native vessel. Procedural success (defined as TIMI 3 flow at the end of procedure) was less likely in patients with previous CABG than in patients who had never undergone CABG (80.7 vs 88.2% respectively, p<0.001). Patients with previous CABG had higher all-cause mortality (30.1% vs 16.7%, p<=0.0001) during the follow-up period (figure 1). After multivariate adjustment this difference persisted (HR: 1.3, 95% CI 1.11 to 1.63, p=0.02). When stratifying prior CABG patients by the type of IRA (figure 2); long term MACE were significant more likely in patients who had bypass graft PCI than in patients that had native vessel PCI, 35.7% versus 20.4% (p=0.03). Figure 1 Figure 2 Conclusions Previous CABG patients with STEMI treated with primary PCI have higher long-term adverse events. The long-term outcome is also worse if the IRA is a bypass graft rather than a native coronary artery.

Introduction The use of primary percutaneous coronary intervention (PCI) in octogenarians to treat ST elevation myocardial infarction (STEMI) is less than in other age groups. This is due in part to underrepresentation in clinical trials and perceived increased risk. We present long-term survival of a large cohort of elderly patients following primary PCI in London. Table 1 Under 80 Over 80 p Value Gender (female) 1800 (19.6%) 474 (45.4%) <0.0001 Hypertension 3692 (42.3%) 501 (51.3%) 0.02 Hypercholesterolaemia 3708 (42.5%) 548 (56.1%) <0.0001 Previous MI 1442 (16.9%) 182 (18.7%) 0.150 Previous CABG 264 (3.0%) 46 (4.6%) 0.010 Multi vessel disease 3821 (41.8%) 562 (54.0%) <0.0001 GPIIb/IIIa 6515 (74.4%) 530 (53.8%) <0.0001 DES use 4058 (45.9%) 311 (30.9%) <0.0001 Access (radial) 2115 (23.4%) 194 (18.8%) 0.001 Procedural success 6932 (88.3%) 736 (84.7%) 0.003 Methods This was an observational study of 10 249 consecutive patients undergoing primary PCI for STEMI at eight London heart attack centres between January 2005 and November 2011. Patient's details were recorded at the time of procedure into the British Cardiac Intervention Society (BCIS) database. Outcome was assessed by all-cause mortality. Anonymous datasets from the eight centres were merged for analysis. The primary end-point was all-cause mortality at a median follow-up of 3.0 years (IQR range 1.2–4.6 years). Results A total of 1051 octogenarians (10.3% of the study population) with an average age of 84.2 years (IQR 80–101) were treated with primary PCI during the study period. Over time, the annual proportion of octogenarians gradually increased from 9.1% in 2005 to 10.5% in 2010. Unsurprisingly, when compared to patients under 80, octogenarian STEMI patients included a higher proportion of women, and had a higher prevalence of hypertension, hypercholesterolaemia, multi-vessel disease, previous infarction and previous CABG (table 1). They additionally were less likely to undergo radial access, receive GPIIb/IIIa inhibitors or a drug-eluting stent. When compared with younger patients, primary PCI in octogenarians was less likely to achieve TIMI flow grade 3. However between 2005 and 2011 the rates of post-procedural TIMI flow grade 3 increased significantly from 80.5% in 2005 to 90% in 2011 (p for trend 0.05). The cumulative incidence of all-cause mortality during follow-up was significantly higher in the octogenarian group compared to the younger subgroup (51.6% vs 12.8%, p<0.0001) (figure 1). As expected, the hazard of death during follow-up increased with age (unadjusted HR 1.069 per year increase (95% CI 1.064 to 1.074), p<0.0001), which persisted after adjustment for other predictors of mortality (HR of 1.059 (95% CI 1.048 to 1.071), p<0.0001). Figure 1 Conclusions Octogenarians constitute an important subgroup of STEMI patients. Data from London's experience would suggest that primary PCI rates are increasing in this group and that despite the high long term mortality, acute/year one rates survival rates are very encouraging.

IntroductionTreatment of supraventricular tachycardia (SVT) with adenosine by paramedics has been investigated and proven to be safe in the USA, but patients (pts) are transferred to hospital. We hypothesised that paramedics can safely treat and discharge pts with regular SVT without transfer to an accident and emergency department and tested this in a randomised controlled trial.MethodsPts presenting with regular narrow complex tachycardia on 12 lead ECG who were heamodynamically stable, with no history of structural or ischaemic heart disease and without contraindication to adenosine were considered for enrolment. Pts were randomised to paramedic treatment (PARA) or admission to hospital (A&E). PARA pts received valsalva manoeuvre at the scene with subsequent administration of 6 mg and 12 mg of adenosine unless the SVT terminated. Pts were taken to A&E if the tachycardia did not terminate, restarted, or the patient (pt) had continuing symptoms, a persistently abnormal ECG (other than T wave inversion) or was heamodynamically unstable. Prior to discharge from the ambulance pts received an information pack and a referral letter for their GP to refer them to an arrhythmia clinic. Pts randomised to A&E were treated as normal and given no information other than that pertaining to the study.ResultsOf the 60 pts (33=F, age 52±19 years) enroled to date, 56% pts had previously attended A&E with palpitations. 2 pts withdrawn as lost to follow up. Results table 1 PARA discharge times were relatively long because 12 pts randomised to PARA were transported to A&E (5 did not terminate arrhythmia, 1 abnormal observations, 4 paramedic felt ECG abnormal (confirmed as minor abnormalitites by expert panel that would not require treatment), 2 abnormal ECG requiring treatment). A panel of 2 arrhythmia experts reviewed records for all PARA pts and confirmed treatment was appropriate for all but would have further assessed 1 pt with lung disease.ConclusionsParamedic treatment and discharge of pts with regular SVT is safe, efficacious and reduces admissions. Cost effectiveness analysis is ongoing.

Introduction During Primary Percutaneous Coronary Intervention (PPCI) post ST-Segment Myocardial Infarction (STEMI), distal embolisation of thrombus may lead to failure to re-establish normal flow in the infarct-related artery. Manual thrombus aspiration has been shown to improve coronary perfusion as assessed by time to ST-segment resolution and myocardial blush grade. Evidence supporting the benefit of thrombus aspiration on clinical outcomes, however, is limited and inconsistent. We aimed to assess the impact of manual thrombectomy on mortality in patients presenting with STEMI across all PPCI centres in London over a 5 year period from 2007 until 2012. Methods This was an observational cohort study of 9935 consecutive patients with STEMI treated with PPCI between 2007 and 2012 at eight tertiary cardiac centres across London, UK. Patient9s details were recorded at the time of the procedure into the British Cardiac Intervention Society (BCIS) database. Outcome was assessed by all-cause mortality. Anonymous datasets from the eight centres were merged for analysis. The primary end-point was all-cause mortality at a median follow-up of 2.0 years (IQR range 1.1–3.1 years). Results Of the 9935 consecutive STEMI patients presenting for PPCI, 2859 had mechanical thrombectomy. Patients who had manual thrombectomy were significantly younger (average age 60.6 vs 62.9) and were less likely to have had a previous myocardial infarction (11.9% of thrombectomy patients vs 14.7% of non-thrombectomy patients). Patients receiving manual thromectomy were found to be significantly more likely to have had PPCI via a radial approach (33.1% in thrombectomy patients vs 19.9% in non-thromectomy patients). Procedural success (defined as TIMI 3 flow at the end of procedure) was found to be significantly more likely in patients receiving manual thrombectomy (89.5% vs 86.7%) (table 1). Patients with thrombectomy use had similar unadjusted all-cause mortality rates to those without thrombectomy use (12.7% vs 16.5%, p=NS) during the 5-year follow-up period (figure 1). After multivariable adjustment thrombectomy use was associated with significantly decreased mortality rates (HR: 0.82, 95% CI 0.68 to 0.9, p=0.04). Conclusion Mechanical thrombectomy use appears to be associated with improved outcome, in the form of decreased mortality, in this large observational trial.

Background Out of hospital cardiac arrest (OOHCA) is an increasingly common clinical conundrum for the interventional cardiologist, largely because paramedic resuscitation is becoming more effective. The 2011–2012 audit of the London Ambulance Service showed an increase in survival to hospital in patients with return of spontaneous circulation (ROSC) from 14% in 2007/2008 to 30% in 2011/2012. We analysed the survival of our cardiac arrest survivors and how eventual diagnosis impacted on outcome. Methods A retrospective analysis of intensive therapy unit (ITU) data over a 20 month period was performed. Patients were either admitted through the Emergency Department or taken directly to the catheterisation laboratory depending on the presence of ST elevation on the presenting ECG. Those attending the catheter laboratory received primary revascularisation (PR) if appropriate. From a variety of sources we obtained survival rates in ITU, hospital and at 30 day post-discharge. Results 108 patients with OOHCA were admitted to our institution during the study period. Of these 55 (51%) patients were admitted via the A&E and 53 (49%) were taken straight to the cath lab. Of the OOHCA taken to the cath lab all patients underwent coronary angiography. PR was performed only on OOHCA patients with conclusive evidence of an occluded vessel 44/108 (41%). The total number of OOHCA that left ITU alive irrespective of cause was 55/108 (51%). The number of OOHCA patients who left ITU after PR was 26/44 (59%) compared with those that did not receive PR 29/64 (45%). The total number of OOHCA patients who left hospital was 49/108 (45%). The total number of patients with PR who left hospital was 23/44 (52%) and those who received no PR was 26/64 (41%). The overall survival at 30 days for OOHCA at KCH was 48/108 (44%). The 30 day survival for those patients receiving PR was 23/44 (52%) and those not receiving PR was 25/64 (39%). The eventual diagnosis in the no ST elevation group was extremely varied and included cardiac and non-cardiac aetiologies. Discussion Improved effectiveness of paramedic resuscitation is increasing the number of OOHCA survivors with ROSC delivered to all major cardiac centres. This is a growing cohort of patients and consensus about optimal care pathways has yet to be reached in the UK. Overall survival in this cohort was higher than expected. It seems from these data that directing patients according to the presence of ST elevation in the ECG is reasonable. Those patients with ST elevation undergoing PR have the best prognosis.

Purpose: The 2005 American Heart Association Guidelines noted the potential use of ventricular fibrillation (VF) waveform analysis to "include prediction of success of cardioversion… and optimization of timing of defibrillation relative to CPR and medication delivery."1 This prospective double-blinded randomized controlled trial was designed to assess the use of a VF waveform analysis algorithm to improve survival.Methods: Out-of-hospital cardiac arrest (OOHCA) patients from two large metropolitan EMS systems were treated with automated external defibrillators (AEDs) randomized to a universal shock-first or VF waveform analysis protocol. Study inclusion was limited to presenting VF of primary cardiac aetiology. VF waveform characteristics were used to calculate a novel score representing VF quality. Patients whose score was below a predefined threshold received either immediate defibrillation or a 2-min period of CPR prior to defibrillation based on AED randomization. The primary outcome was survival to hospital discharge.Results: Between May 5, 2006 and June 30, 2009, a total of 6738 OOHCA patients were enrolled. 5751 patients were excluded, the majority (85%) due to a non-VF presenting rhythm. Of the 987 included cases, 540 (54.7%) presented below threshold and comprised the primary analysis group. Based on the AED randomization, 262/540 patients were given two minutes of CPR prior to defibrillation and 278/540 patients were treated with a shock-first protocol. The initial VF score was highly predictive (p < 0.001) for survival to hospital discharge overall. For subjects below threshold, no significant differences were identified between the shock-first and CPR-first protocols for ROSC (27% vs. 29%, p = 0.57), sustained ROSC (20% vs. 22%, p = 0.75), and survival to admission (23% vs. 22%, p = 1.00) or discharge (7% vs. 7%, p = 1.00).Conclusions: Initial VF score is highly predictive for subsequent survival to hospital discharge. However, its use to guide initial CPR treatment for patients with low quality VF did not alter survival. Purpose: The 2005 American Heart Association Guidelines noted the potential use of ventricular fibrillation (VF) waveform analysis to "include prediction of success of cardioversion… and optimization of timing of defibrillation relative to CPR and medication delivery."1 This prospective double-blinded randomized controlled trial was designed to assess the use of a VF waveform analysis algorithm to improve survival. Methods: Out-of-hospital cardiac arrest (OOHCA) patients from two large metropolitan EMS systems were treated with automated external defibrillators (AEDs) randomized to a universal shock-first or VF waveform analysis protocol. Study inclusion was limited to presenting VF of primary cardiac aetiology. VF waveform characteristics were used to calculate a novel score representing VF quality. Patients whose score was below a predefined threshold received either immediate defibrillation or a 2-min period of CPR prior to defibrillation based on AED randomization. The primary outcome was survival to hospital discharge. Results: Between May 5, 2006 and June 30, 2009, a total of 6738 OOHCA patients were enrolled. 5751 patients were excluded, the majority (85%) due to a non-VF presenting rhythm. Of the 987 included cases, 540 (54.7%) presented below threshold and comprised the primary analysis group. Based on the AED randomization, 262/540 patients were given two minutes of CPR prior to defibrillation and 278/540 patients were treated with a shock-first protocol. The initial VF score was highly predictive (p < 0.001) for survival to hospital discharge overall. For subjects below threshold, no significant differences were identified between the shock-first and CPR-first protocols for ROSC (27% vs. 29%, p = 0.57), sustained ROSC (20% vs. 22%, p = 0.75), and survival to admission (23% vs. 22%, p = 1.00) or discharge (7% vs. 7%, p = 1.00). Conclusions: Initial VF score is highly predictive for subsequent survival to hospital discharge. However, its use to guide initial CPR treatment for patients with low quality VF did not alter survival.

Purpose: Significant variation has been described among Emergency Medical Services (EMS) systems throughout the world with respect to out-of-hospital cardiac arrest (OOHCA). We sought to describe such variation among two of the world's busiest EMS systems, each responding to over one million calls annually.1–3 Methods: Data collected as part of a large randomized controlled out-of-hospital resuscitation trial in New York City (NYC) and London were analyzed. Enrollment began in London on May 5, 2006 and in NYC on May 13, 2007. Both sites concluded enrolment on June 30, 2009. Results: A total of 6738 OOHCA cases were enrolled. Ventricular fibrillation (VF) was less likely to be the presenting rhythm among patients in NYC (16.1% vs 22.3%, p < 0.0001), though the annual incidence of VF was higher in that system (3.46 vs 2.16 per 100,000). Among patients presenting with bradyasystolic rhythms, survival was better in London though poor in both cities (1.89% vs 1.01%, p = .02). VF patients in NYC were typically younger (median age 62 years vs 70 years), less likely to have received bystander CPR (24.4% vs 46.9%, p < 0.0001), and experienced shorter EMS response time (median = 3 min, 38 s vs 5 min, 24 s). No differences were noted in return of spontaneous circulation (42.5% vs 41.2%, p = .70), though VF patients in NYC were more likely to be declared deceased in the field (8.9% vs 2.0%, p < .0001). There were no differences in survival to admission (33.5% vs 38.2%, p = .12) or survival to discharge (15.5% vs 17.8%, p = .34). Among the subgroup of EMS-witnessed VF cardiac arrest patients (n = 52), there was also no difference in survival to admission (50.0% vs 56.7%, p = .78) or discharge (31.8% vs 40.0%, p = .58). Conclusions: Despite differences in the characteristics of OOHCA in New York and London, the overall survival rates were remarkably similar between the two cities.

Purpose: We compared characteristics of the ventricular fibrillation (VF) waveform and Emergency Medical Service (EMS) response time in their ability to predict patient outcomes from out-of-hospital cardiac arrest (OOHCA). Although some studies have shown EMS response time to be a strong predictor of patient outcome, it is difficult to measure and may not accurately reflect patient down-time.1–4 Methods: ECG data collected during a large multi-center study involving 987 out-of-hospital cardiac arrests with patients presenting in VF was analyzed. The ECG was recorded on Philips Healthcare FR2 automatic external defibrillators (AEDs) and a 5 s segment of the initial recorded rhythm was analyzed using a proprietary algorithm to calculate a VF score. EMS response time was measured from call to ambulance arrival on scene. Using logistic regression, the predictive ability of the VF waveform score and EMS response time was assessed for the following outcomes: return of spontaneous circulation (ROSC), sustained-ROSC, hospital admission and discharged alive from hospital. Results: Odds ratios [95% confidence limits] for the VF score and EMS response time respectively, ROSC: 3.84 (2.98–4.95) p < 0.0001, vs. 0.96 (0.91–1.01) p = 0.12; S-ROSC: 3.95 (3.02–5.17) p < 0.0001 vs. 0.98 (0.93–1.04) p = 0.51; admission: 4.04 (3.10–5.27) p < 0.0001 vs. 0.99 (0.93–1.05) p = 0.66; discharge: 5.15 (3.65–7.31) p < 0.0001 vs. 0.98 (0.92–1.05) p = 0.61. The Pearson correlation coefficient between VF score and EMS response time was −0.05 (p = 0.12). Conclusions: Using the presenting VF rhythm, we were able to calculate a score which was highly predictive of patient outcomes. EMS response time was not a strong predictor. This VF waveform analysis may be used to direct resuscitations by identifying patients who are likely to respond well to standard treatment with positive outcomes and those patients who may benefit from alternative procedures.

Purpose: This study examined the impact of three critical environmental and societal factors on the initial ECG waveform and eventual patient outcomes: bystander witness, bystander CPR and EMS witness using a VF score. This score predicts survival outcomes in out-of-hospital-cardiac arrest (OOHCA) patients better than traditional predictors such as response times.1Russell J.K. White R.D. Crone W.E. Analysis of the ventricular fibrillation waveform in refibrillation.Crit Care Med. 2006; 34: S432-S437Crossref PubMed Scopus (5) Google ScholarMethods: ECG data was collected during a multi-center, randomized controlled trial on OOHCA patients presenting in VF. Waveform characteristics were used to calculate a novel score representing VF quality using a Philips Healthcare AED algorithm.Results: Cardiac arrests were witnessed by EMS in 5.3% (52/980) of the study population. In 77% (755/980) of the cases, the cardiac arrest was bystander witnessed. Bystander CPR was provided in 38.4% of these cases. The median score of the presenting VF in EMS witnessed arrests was 71% higher than that of non-witnessed arrests with a corresponding improvement in survival of 27.2%. When compared to VF scores of patients who had a bystander witnessed cardiac arrest, the EMS witnessed VF score was 46% higher with a corresponding improvement in survival of 19.6%. Similarly, the effect of bystander witness alone versus not witnessed resulted in a 17% higher VF score with a 7.6% increase in survival. These three gains in VF score and survival were significant (p < 0.0001, Kruskal–Wallis). Bystander CPR, resulted in a VF score gain of 26.3% (Wilcoxan p < 0.0001) and a corresponding significant increase in survival of 11.4% when compared with cardiac arrests that were bystander witnessed but received no bystander CPR.Conclusions: Presenting VF scores and corresponding survival rates are significantly higher for patients who have a witnessed cardiac arrest and received bystander CPR. Thus the VF score is not only reflective of the VF quality but also inherently related to treatability and highly predictive of survival and thereby could be used to guide protocols. Purpose: This study examined the impact of three critical environmental and societal factors on the initial ECG waveform and eventual patient outcomes: bystander witness, bystander CPR and EMS witness using a VF score. This score predicts survival outcomes in out-of-hospital-cardiac arrest (OOHCA) patients better than traditional predictors such as response times.1Russell J.K. White R.D. Crone W.E. Analysis of the ventricular fibrillation waveform in refibrillation.Crit Care Med. 2006; 34: S432-S437Crossref PubMed Scopus (5) Google Scholar Methods: ECG data was collected during a multi-center, randomized controlled trial on OOHCA patients presenting in VF. Waveform characteristics were used to calculate a novel score representing VF quality using a Philips Healthcare AED algorithm. Results: Cardiac arrests were witnessed by EMS in 5.3% (52/980) of the study population. In 77% (755/980) of the cases, the cardiac arrest was bystander witnessed. Bystander CPR was provided in 38.4% of these cases. The median score of the presenting VF in EMS witnessed arrests was 71% higher than that of non-witnessed arrests with a corresponding improvement in survival of 27.2%. When compared to VF scores of patients who had a bystander witnessed cardiac arrest, the EMS witnessed VF score was 46% higher with a corresponding improvement in survival of 19.6%. Similarly, the effect of bystander witness alone versus not witnessed resulted in a 17% higher VF score with a 7.6% increase in survival. These three gains in VF score and survival were significant (p < 0.0001, Kruskal–Wallis). Bystander CPR, resulted in a VF score gain of 26.3% (Wilcoxan p < 0.0001) and a corresponding significant increase in survival of 11.4% when compared with cardiac arrests that were bystander witnessed but received no bystander CPR. Conclusions: Presenting VF scores and corresponding survival rates are significantly higher for patients who have a witnessed cardiac arrest and received bystander CPR. Thus the VF score is not only reflective of the VF quality but also inherently related to treatability and highly predictive of survival and thereby could be used to guide protocols.

Introduction: The 2005 American Heart Association Guidelines recommend defibrillation "as soon as possible" for emergency medical service (EMS)-witnessed out-of-hospital cardiac arrest (OOHCA).1 In such cases, ventricular fibrillation (VF) will likely have little time to deplete myocardial substrates or experience significant wavebreak, making it amenable to immediate defibrillation. We sought to describe the initial characteristics of VF waveforms for EMS-witnessed arrests and to relate these to patient outcome. Methods: Data collected as part of an international prehospital resuscitation trial involving OOHCA presenting in VF of primary cardiac etiology was analyzed. Waveform characteristics were used to calculate a score representing VF quality for all patients. The predictive value of the VF score for survival outcomes was assessed. EMS witnessed cardiac arrests were compared to non-EMS witnessed cases with respect to VF scores and patient outcome. Results: For all out-of-hospital-cardiac-arrests (n = 985), the VF score was highly predictive for all patient outcomes (max p < 0.02). EMS providers witnessed 52/985 (5.3%) cardiac arrests. The median normalized VF score for these patients was 0.144 (range 0.026–1.000). This was significantly higher than the median score for patients whose arrests were not witnessed by EMS providers (0.096, range 0.019–0.562, p = 0.0001). Outcomes were better among EMS witnessed cardiac arrests: return of spontaneous circulation (ROSC) (62% vs 41%, p = .004), sustained ROSC (55% vs 33%, p = .002), survival to hospital admission (54% vs 35%, p = .007), and survival to hospital discharge (37% vs 15%, p = .0003). Conclusion: Though VF quality was higher among EMS-witnessed cardiac arrests, there was a surprising range among initial VF scores in this population and overlap with those arrests not witnessed by EMS, representing a wide array of waveform morphology for new-onset VF. Given the correlation between outcome and VF scores in this population, waveform analysis for outcome prediction and potential therapeutic guidance may be useful.

Purpose: Out-of-hospital cardiac arrest patients who do not respond to resuscitation efforts in the field rarely survive to hospital admission or discharge. In fact, termination of resuscitation rules suggest these patients should not be transported to hospital. We sought to determine the characteristics of the small group who survive to hospital admission despite unsuccessful pre-hospital resuscitation. Methods: Data collected from 985 ventricular fibrillation (VF) pre-hospital cardiac arrests of cardiac aetiology, as part of a large multi-site randomised controlled trial, were analysed. Comparisons were made between those successfully resuscitated in the field (achieved return of spontaneous circulation (ROSC)) and those not. Results: ROSC was achieved in the field by 412/985 patients (41.8%). Of these, 411 (99.8%) were transported to hospital, 317 (76.9%) were admitted and 157 (38.1%) survived to hospital discharge. Among the 573 patients who did not achieve ROSC, 518 (90.4%) were transported to hospital, 32 (5.6%) were admitted and 5 (0.9%) survived to hospital discharge. No significant differences were noted for age, ethnicity, or other arrest characteristics, despite a trend toward female gender among those surviving to hospital admission despite not achieving ROSC when compared to those who did (44% vs. 29%, p = .11). The median length of stay for those who were admitted to hospital despite unsuccessful pre-hospital resuscitation was 3.0 days (1.5 days for those who did not survive). For those that were admitted to hospital after achieving ROSC in the field, the median length of stay was 8 days (2.0 days for those who did not survive). Conclusions: Despite unsuccessful resuscitation in the field, patients presenting with VF may survive to hospital discharge suggesting these patients should always be transported to hospital. Our data indicates that only a small burden would be placed on receiving hospitals in order to maximise the potential survival of such patients.

Purpose: A limited amount of data has been published regarding the effects of body weight on out-of-hospital cardiac arrest.1,2 We sought to describe the effects of obesity on ventricular fibrillation (VF) waveform characteristics, defibrillation, and outcomes. Methods: Between May 13, 2007 and June 30, 2009, the Fire Department of New York (FDNY) participated in a large, multicenter randomized controlled prehospital resuscitation study. Post-arrest interviews with the EMS providers including an assessment for "obesity," defined as 300 lbs or more. Data collected during the course of this study was used to assess the impact of obesity on cardiac arrest characteristics, including a calculated VF score based on the first five seconds of the rhythm analysis and representing the quality of the initial VF waveform. Results: A total of 4127 patients were enrolled by the FDNY during the study period, of whom 529 presented in VF of primary cardiac etiology. Data regarding the presence or absence of obesity was available all but 5 patients. Patients were considered to be significantly obese in 42/525 cases (8.0%). Obese patients were slightly though not significantly younger than non-obese patients (59.0 years vs 61.8 years). Initial waveform capnography values did not vary between the two groups (25.3 mmHg vs 25.6 mmHg). The median normalized VF score was similar among obese patients as compared to non-obese patients (.091, range .032–.312 versus .096, range .021–1.00, p = .48), while the average impedance was higher for obese patients (89.7 ohms vs 78.1 ohms). The average number of defibrillatory shocks for obese patients was less than that for the non-obese (1.48 vs 1.56, p = .035). Rates for return of spontaneous circulation, survival to hospital admission, and survival to hospital discharge did not vary between the two groups. Conclusions: Our data provides supporting evidence to suggest that obesity does not adverse effect VF characteristics, treatment or outcome.

Purpose: Racial disparities have been the focus of a number of healthcare studies to date, including those that have focused on out-of-hospital cardiac arrest (OOHCA).1,2 We sought to describe the characteristics and outcomes of OOHCA patients presenting in ventricular fibrillation (VF) as a function of race.Methods: Data collected by London Ambulance Service (LAS) and the Fire Department of New York (FDNY) between May 2006 and June 2009 as part of a randomized controlled prehospital resuscitation trial, including descriptions of each patient's race as described EMS personnel, was analyzed.Results: Data from 987 OOHCA patients presenting in VF of primary cardiac etiology were analyzed. Information regarding race was available for 854 (86.5%) patients. Non-white patients were significantly younger than white patients (LAS 60.0 years vs 68.3 years, FDNY 56.7 years vs 66.3 years, overall 57.2 years vs 67.5 years; max p < .001). In New York, nonwhite patients were less likely to receive bystander CPR as compared to white patients (19.9% vs 30.0%, p = .01). In London, no differences were noted with respect to the likelihood of receiving bystander CPR. There was no difference between nonwhites and whites for return of spontaneous circulation (LAS 41.3% vs 44.2%, p = .75; FDNY 43.1% vs 40.9%, p = .65; overall 42.8% vs 42.8%, p = 1.00) or survival to hospital admission (LAS 40.0% vs 38.6%, p = 0.87; FDNY 36.0% vs 31.3%, p = .30; overall 36.5% vs 35.5%, p = .77), though there was a trend toward improved survival to discharge among nonwhites (LAS 28.9% vs 17.0%, p = .07; FDNY 18.0% vs 13.0%, p = .14, overall 19.6% vs 15.3%, p = .13).Conclusions: Although no significant differences were noted with respect to outcome, the younger age and potential to improve bystander CPR rates for nonwhite patients represents cause for focused educational programs and community outreach as part of on-going efforts to improve cardiac arrest survival. Purpose: Racial disparities have been the focus of a number of healthcare studies to date, including those that have focused on out-of-hospital cardiac arrest (OOHCA).1,2 We sought to describe the characteristics and outcomes of OOHCA patients presenting in ventricular fibrillation (VF) as a function of race. Methods: Data collected by London Ambulance Service (LAS) and the Fire Department of New York (FDNY) between May 2006 and June 2009 as part of a randomized controlled prehospital resuscitation trial, including descriptions of each patient's race as described EMS personnel, was analyzed. Results: Data from 987 OOHCA patients presenting in VF of primary cardiac etiology were analyzed. Information regarding race was available for 854 (86.5%) patients. Non-white patients were significantly younger than white patients (LAS 60.0 years vs 68.3 years, FDNY 56.7 years vs 66.3 years, overall 57.2 years vs 67.5 years; max p < .001). In New York, nonwhite patients were less likely to receive bystander CPR as compared to white patients (19.9% vs 30.0%, p = .01). In London, no differences were noted with respect to the likelihood of receiving bystander CPR. There was no difference between nonwhites and whites for return of spontaneous circulation (LAS 41.3% vs 44.2%, p = .75; FDNY 43.1% vs 40.9%, p = .65; overall 42.8% vs 42.8%, p = 1.00) or survival to hospital admission (LAS 40.0% vs 38.6%, p = 0.87; FDNY 36.0% vs 31.3%, p = .30; overall 36.5% vs 35.5%, p = .77), though there was a trend toward improved survival to discharge among nonwhites (LAS 28.9% vs 17.0%, p = .07; FDNY 18.0% vs 13.0%, p = .14, overall 19.6% vs 15.3%, p = .13). Conclusions: Although no significant differences were noted with respect to outcome, the younger age and potential to improve bystander CPR rates for nonwhite patients represents cause for focused educational programs and community outreach as part of on-going efforts to improve cardiac arrest survival.