Variations in atrial fibrillation screening after ischemic stroke or transient ischemic attack in Sweden

Background/Introduction

The risk of recurrent stroke and mortality is high among patients with ischemic stroke or transient ischemic attack (TIA) and untreated atrial fibrillation (AF). Hence, AF screening after an event has high priority in national and international guidelines. Despite the abundance of evidence on AF detection using different AF screening modalities, there is still no evidence on a prognostic benefit of ECG monitoring post ischemic stroke. There is a risk for variations in clinical practice for AF screening after ischemic cerebrovascular events due to this gap of evidence.

Purpose

The aim of this study was to investigate the clinical practice of AF screening after TIA or ischemic stroke at Swedish stroke units.

Methods

In collaboration with the stakeholders of the Swedish stroke register (Riksstroke) important fields to study were identified, e.g. AF screening method, first choice of method (multiple answers possible), monitoring duration, clinical follow-up etc. A draft for a digital survey was constructed and then tested and revised by 5 stroke consultants. The survey consisted of 18 multiple choice questions with free text comments and was sent by e-mail to the medical supervisors at all stroke units in Sweden in November 2021.

Results

All 72 stroke units in Sweden responded to the survey. Almost all (69/72) stroke units reported that ≥75% of ischemic stroke patients are screened for AF. Of the stroke units 81% had inpatient telemetry as their first choice of AF screening method (Figure 1), but 7% had no access to inpatient telemetry. In case of inpatient telemetry, 30% reported 0–24 hours and 54% reported 24–48 hours as their standard monitoring time. Most had the attending physician at the stroke unit as the primary ECG reader, some with access to support from cardiologist. Different standard monitoring durations for Holter were used (Figure 2) and 17% reported Holter as their first choice of AF screening method. Approximately 85% reported repeated ECG monitoring if high suspicion of cardiac embolization, preferably with repeated Holter (73%) or handheld ECG (49%). Implantable loop recorder (6%), event loop recorder (14%) and 2 weeks registration with ECG-patch (3%) was more infrequently used for this purpose.

Conclusions

Clinical practice for AF screening after ischemic stroke or TIA at Swedish stroke units showed considerable variations with a range of different AF screening methods and monitoring durations. Further, the standards and quality of inpatient ECG monitoring is unknown. There is an urgent need for evidence and evidence-based recommendations in this field, the present situation also implies inequality in care.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Stiftelsen Hjartat

Validation of a novel smartphone-based photoplethysmographic method for ambulatory heart rhythm diagnostics

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Vinnova - The Swedish Agency for Innovation Systems.

Region Stockholm Innovation Fund.

Introduction

Devices for long-term and ambulatory recording of heart rhythm have limited availability within health care systems worldwide, potentially leading to missed diagnoses and limitations in peri-procedural heart rhythm management. As smartphones are becoming ubiquitous the availability of heart rhythm diagnostics and management of atrial fibrillation (AF) using smartphone photoplethysmography (PPG) compared to electrocardiography (ECG) is increasing. Previous validation studies of smartphone-PPG applications have all been performed under supervision in healthcare settings. In addition, no previous study has validated smartphone-PPG compared to simultaneous ECG recordings, with manual heart rhythm interpretation of the PPG recordings nor have they included patients with atrial flutter (AFL).

Purpose

The aim of this study was to validate a novel smartphone-PPG method for heart rhythm diagnostics in patients with AF and/or AFL when in use unsupervised in an ambulatory setting.

Methods

Unselected patients undergoing direct current cardioversion at a University Hospital for treatment of AF or AFL were asked to perform one-minute heart rhythm recordings post-treatment at least twice daily for 30 days in their home environment. All included were provided with an unmodified iPhone 7 smartphone running the CORAI Heart Monitor PPG application simultaneously with a single-lead ECG recording (KardiaMobile). PPG and ECG recordings were interpreted independently by two readers.

Results

In total 280 patients, with median age of 69.0 years (31% women) were included from November 2018 to July 2020 and registered 18 005 simultaneous PPG and ECG recordings. Of the PPG recordings 96.9% had sufficient quality for diagnosis compared to 95.1% of the ECG recordings (p < 0.001). Precardioversion ECG recordings were interpreted as AF in 82.1%, AFL in 14.3% and as having insufficient quality for diagnosis in 3.6% of the patients. After removal of recordings with insufficient quality 69.7% of ECG recordings were interpreted as sinus rhythm, 28.2% as AF and 2.1 % as AFL. Manual interpretation of the PPG recordings diagnosed AF/AFL (sensitivity) in 97.7% and sinus rhythm (specificity) in 99.4% of the recordings compared to manually interpreted ECG recordings, with an overall accuracy of 98.9%. Results excluding recordings interpreted as AFL on ECG or PPG diagnosed AF (sensitivity) in 99.0% and sinus rhythm (specificity) in 99.7% of the recordings, with an overall accuracy of 99.5%.

Conclusion

A novel smartphone-PPG method can be used by patients unsupervised in their home environment for accurate heart rhythm diagnostics of AF and AFL with high sensitivity and specificity.

Prevalence of silent atrial fibrillation in high-risk patients - preliminary results from a European three-country handheld ECG-screening study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Helsefonden Lilly and Herbert Hansens Foundation

Introduction

Patients with atrial fibrillation (AF) should in most cases be offered prophylactic anticoagulation treatment to prevent a stroke. However, the arrhythmia can appear without symptoms, so-called silent AF. Even without symptoms AF constitutes a risk for stroke.

Purpose

To screen high-risk patients with diabetes type 2 (DMII) or heart failure (CHF) for silent AF.

Methods

We included patients > 64 years with either DMII or CHF from out-patient clinics and local health centers. Exclusion criteria were known AF, anticoagulation treatment, recent stroke, or an implanted pacemaker or ICD. Patients were recruited from a total of eleven study centers in three countries. All underwent 14-days of intermittent ECG screening with a handheld ECG recording four times each day; the recordings were digitally stored. AF was diagnosed in cases of irregular heart rhythm and absence of P waves on at least one recording (thirty seconds) or on at least two recordings for a minimum of ten seconds.

Results

In total, 813 patients were included, 541 of these with DMII. The mean age was 73,4 years ± 5,8 SD, 40,7% of the patients were female.

In the DMII group thirteen patients (2.4%) were diagnosed with silent AF and offered anticoagulation. In the CHF group six (2.2%) patients had diagnosed silent AF on the handheld ECG. The prevalence of AF increased with increasing age, see Table 1. Thus, in the youngest group AF was diagnosed in 1.3% of the patients compared to 3.9 % in the age group 75 years or older.

Conclusions

Screening for silent AF in high-risk patients with DMII or CHF seems worthwhile, especially in patients 75 years or older. Abstract Figure. ECG with atrial fibrillation

Large-scale screening studies for atrial fibrillation - is it worth the effort?

Atrial fibrillation (AF) is a common disease with increasing prevalence, approximately 3.2% in the adult population. In addition, about one third of AF cases are considered asymptomatic. Due to increased longevity, increased detection and increased prevalence of risk factors, the prevalence of AF is expected to at least double by the year 2060. Patients with AF have an increased risk for ischaemic stroke, heart failure, death and cognitive decline. Treatment with oral anticoagulation reduces the risk of ischaemic stroke and mortality, and the effect on cognitive decline is being studied. Based on the increasing prevalence of AF, its often asymptomatic and paroxysmal presentation and the efficacy of oral anticoagulation treatment, screening for AF has been proposed. AF seems to fulfil most of the Wilson-Jungner criteria for screening issued by the World Health Organization, but some knowledge gaps remain, gaps that will be addressed by several ongoing studies. The knowledge gaps in AF screening consist of the magnitude of the net benefit or net harm inflicted by AF screening because the oral anticoagulation treatment will also increase the risk of bleeding, and the psychological effects of AF screening are not very well studied. So far, the AF screening recommendations issued by the European Society of Cardiology have had limited impact on national and regional AF screening activities. Several large-scale AF screening studies will report results on hard endpoints within the next few years, and these results will hopefully manifest AF as a cardiovascular disease which we need to pay more attention to.

Elevated echocardiographic markers for left atrial stiffness and fibrosis in patients with paroxysmal atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Danderyds Hospital

Background

Atrial fibrillation (AF) is associated with atrial disease expressing left atrial (LA) structural remodeling with increased fibrosis and stiffness. Transthoracic echocardiography (TTE) is the first imaging modality of choice for the evaluation of LA volume index (LAVI) and function. However TTE allows new approaches for LA anatomical and functional analysis such as LA stiffness index (LASI) calculation based on LA global longitudinal strain (GLS), LA activation time and LA Integrated Backscatter (IBS). LA activation time is a novel parameter, considered as an echocardiographic surrogate analysis for LA fibrosis. Echocardiographic derived IBS can noninvasively quantify myocardial fibrosis in the left ventricle, allowing a similar alternative analysis for LA fibrosis.

Purpose

To investigate potential  LA structural and functional changes in paroxysmal AF patients by measuring LA activation time, LASI and LA IBS compared with age-matched control group.

Methods

In total, 75 paroxysmal AF patients and 99 age-matched control group patients (mean age 77 ± 0.4) were enrolled from STROKESTOP2 study. Patients with paroxysmal AF were included from a subgroup of newly screened-diagnosed AF. TTE examinations were analyzed retrospectively offline using dedicated software. NTproBNP levels ( ≤ 900 ng/L) was an enrollment criterium. LA activation time was acquired by measuring the time delay between the onset of the P-wave on ECG and the peak of the Á –wave on the Tissue Doppler (TD) tracing in the lateral LA wall. LASI was calculated as the ratio of E/é to LA-GLS. LA IBS was obtained as the intensity difference between the LA lateral wall and the pericardium, at QRS peak.

Results

There was a significant increase of LASI (0.53 ± 0.21 vs. 0.41 ± 0.22, P < 0.05) and LA IBS (14 ± 7.1 dB vs. 11 ± 6.3 dB, P < 0.05) in the AF group compared to the control group. Feasibility for LASI resulted as 64 %, respectively 91 % for LA IBS. LA activation time was significantly prolonged in the AF group (157 ± 34 ms vs. 134 ± 18 ms, P < 0.05) with a feasibility of 44 %. In the AF group, 45 patients (60 %) expressed normal LAVI <34 ml/m2. No significant difference was revealed concerning LAVI (P > 0.05) between the groups (AF group with normal LAVI). Although LASI, LA IBS and LA activation time remained significant increased in the AF group (P < 0.05). No significant difference was shown regarding NT-proBNP levels. (P > 0.05) between the AF group 243 (179-420) ng/L and the control group 219 (160-317) ng/L.

Conclusions

Indices reflecting LA stiffness and echocardiographic parameters associated with LA fibrosis, were elevated in patients with paroxysmal AF compared to age-matched controls. These findigs might non-invasively provide additional information in paroxysmal AF patients with normal LA size.

Echocardiographic speckle tracking provides incremental value for left atrial function in patients with paroxysmal atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Danderyds Hospital

Background

Atrial fibrillation (AF) is associated with progression of left atrial (LA) structural and functional changes. It is well acknowledged that AF over time promotes LA enlargement. Transthoracic echocardiography (TTE) is important in decision making for further treatment. Initially, new onset of AF such as paroxysmal AF can occur in the absence of LA enlargement. Therefore assessment of LA volume index (LAVI) as follow-up can mislead LA evaluation. LA global longitudinal strain (LA-GLS) is a novel parameter assessed with two-dimensional (2D) speckle tracking (ST). LA-GLS allows quantification of LA myocardial deformation by measuring reservoir function which reflects LA compliance during left ventricular systole.

Purpose

Our aim is to study potential differences in LA myocardial deformation as assessed by LA-GLS in paroxysmal AF patients compared with aged-matched control group.

Methods

A total of 75 paroxysmal AF patients and 99 control aged-matched patients (mean age, 77 ± 0.4) were enrolled from STROKESTOP2 study. Patients with paroxysmal AF were included from a subgroup of newly screened-diagnosed AF. TTE examinations were analyzed retrospectively offline using dedicated software. NT-proBNP ≤ 900 ng/L was an inclusion criteria. Besides conventional echocardiographic parameters, LA-GLS was measured using 2D-ST in biplane during systole.

Results

There was a significant LA-GLS reduction in the paroxysmal AF group compared to the control group (19 ± 6.1 % vs. 28 ± 7.2 %, P < 0.001) with a feasibility of 70 %. In the AF group, 45 patients (60 %) expressed normal LAVI <34 ml/m2. No significant difference was revealed concerning LAVI (P > 0.05) between the groups (AF group with normal LAVI), yet LA-GLS remained significant reduced in the AF group (P < 0.001). No significant difference was shown regarding NT-proBNP levels (P > 0.05) between the AF group 243 (179-420) ng/L and the control group 219 (160-317) ng/L.

Conclusion

LA-GLS allows early detection of LA myocardial deformation dysfunction before LA enlargement in patients with paroxysmal AF. This findig provides incremental information to conventional echocardiographic parameters of LA. Whether early detection of LA dysfunction using LA-GLS can contribute to better risk stratification and cardiac therapy improvement requires to be further investigated.

Use of oral anticoagulants after ischaemic stroke in patients with atrial fibrillation and cancer

BACKGROUND AND OBJECTIVES

The use of oral anticoagulants (OACs) amongst patients with atrial fibrillation (AF) has increased in the last decade. We aimed to describe temporal trends in the utilization of OACs for secondary prevention after ischaemic stroke amongst patients with AF and active cancer.

METHODS

This is a cross-sectional and cohort study of patients with active cancer (n = 1518) and without cancer (n = 50 953) in the Swedish national register Riksstroke, including all patients with ischaemic stroke between 1 July 2005 and 30 December 2017, discharged with AF. Prescription and dispensation before and after the introduction of nonvitamin K OACs (NOACs) in late 2011 were compared. We used logistic and Cox regression to analyse associations with OAC use, adjusting for hospital clustering and the competing risk of death.

RESULTS

The proportion of cancer patients with AF prescribed OACs at discharge after ischaemic stroke increased by 40.2% after 2011, compared with 69.3% in noncancer patients during the same period. Stroke and bleeding risk scores remained similar between patients with and without cancer. OAC dispensation during the following year did not increase as much in cancer patients (43.8% to 64.5%) as that in noncancer patients (46.0% to 74.9%), and the median time to OAC dispensation or censoring was significantly longer in cancer patients (94 vs. 30 days).

CONCLUSION

OAC treatment in poststroke patients with AF and active cancer has increased after the introduction of NOACs. However, the growing treatment gap in these patients compared to that in noncancer patients raises the possibility of underutilization.

P992Socio-demographic inequalities in the uptake of screening for atrial fibrillation within the STROKESTOP II study: support for decentralised screening

Funding Acknowledgements

Roche Diagnostics, The Swedish Heart and Lung Foundation, Carl Bennett AB

Background

To prevent stroke as a first clinical manifestation of atrial fibrillation (AF), screening for AF has been suggested. In the STROKESTOP I (SSI) study, participation was significantly influenced by socio-demographic and geographic factors.

Purpose

The main aim was to improve participation in the STROKESTOP II (SSII) study, especially aiming at socioeconomically weaker groups.

Methods

As in the SSI study, in the SSII study all 75/76-year-olds were randomised 1:1 to either a screening arm or a control arm. The individuals in the screening arm were invited to an AF-screening-program. Two screening sites were added in the SSII study, located closer to low-income neighbourhoods with very low participation rates in the SSI study. Information on each invitee’s residential parish was used for a geo-mapping analysis of the geographical disparities in participation. Individual data for the participants and non-participants were obtained with respect to the following socioeconomic variables: educational level, disposable income, immigrant and marital status. Geographic and socio-demographic disparities in the uptake of the SS2 study were analysed and the results compared between the STROKESTOP trials.

Results

Overall, higher participation was observed in those with higher education, high income as well as among non-immigrants and married individuals. Participation between the SSI and SSII improved significantly in the two areas where additional screening sites were introduced. These improvements were generally significant, in each population group according to the socio-demographic characteristics.

Conclusion

Decentralisation of the screening sites in an AF-screening-program had significant impact on the screening uptake. Addition of local screening sites in areas with a very low uptake may have a beneficial impact on the uptake across the full spectrum of socio-demographic groups

Abstract Figure. Participation map

Occurrence, characteristics, and outcome of patients hospitalized with a diagnosis of acute myocardial infarction who do not fulfill traditional criteria

BACKGROUND

The diagnosis of acute myocardial infarction (AMI) is traditionally based on clinical history, elevation of serum enzyme activity, and typical changes in the electrocardiogram (ECG); however, not all patients who develop AMI fulfill these criteria on discharge from hospital.

HYPOTHESIS

The aim of the study was to evaluate (1) the frequency with which the traditional criteria for AMI are not fulfilled among patients diagnosed with AMI on discharge, and (2) whether patients with and without these criteria differ in terms of characteristics, treatment, and outcome.

METHODS

All patients aged < 75 years and hospitalized in the municipality of Göteborg with a discharge diagnosis of AMI were included. Fulfillment criteria for AMI were two of the following three points: (1) chest pain, (2) increase in cardiac enzymes, and (3) development of Q waves.

RESULTS

In all, 1,188 admitted patients, 27% of whom were women, were included in the analysis. Of these, 193 (16%) did not fulfill the traditional criteria for AMI. These patients had an in-hospital mortality rate of 48%; of these, 59% died a sudden death, and of those who were autopsied (62%), 96% showed signs of a fresh AMI. The most common symptom on admission to hospital in patients who did not fulfill the traditional criteria was chest pain (34%), followed by dyspnea (27%) and fatigue (14%). Of those who died suddenly, fewer than half had been admitted to the coronary care unit.

CONCLUSION

Patients diagnosed with AMI who do not fulfill the traditional diagnosis criteria have high mortality. On admission to hospital, the initial suspicion of AMI is often vague. Measures for earlier detection of life-threatening coronary artery disease among these patients are warranted.

Characteristics and outcome in out-of-hospital cardiac arrest when patients are found in a non-shockable rhythm

AIM

To define factors associated with an improved outcome among patients suffering out-of-hospital cardiac arrest (OHCA) who were found in a non-shockable rhythm.

PATIENTS

All the patients included in the Swedish OHCA registry between 1990 and 2005 in whom resuscitation was attempted, who were found in a non-shockable rhythm and where either the OHCA was witnessed by a bystander or was not witnessed.

RESULTS

In all, 22,465 patients fulfilled the inclusion criteria. Their mean age was 67 years, 32% were women, 57% were witnessed, 64% had a cardiac aetiology, 71% occurred at home and 34% received bystander cardiopulmonary resuscitation (CPR). Survival to 1 month was 1.3%. The following were independently associated with an increased chance of survival: 1/Decreasing age, 2/Witnessed arrest, 3/Bystander CPR, 4/Cardiac arrest outside home, 5/Shorter ambulance response time and 6/Need for defibrillatory shock. If these six criteria were fulfilled (age and ambulance response time below the median), survival to 1 month increased to 12.6%. If no criteria were fulfilled, survival was 0.15%.

CONCLUSION

The overall survival among patients with an OHCA found in a non-shockable rhythm is very low (1.3%). Six factors associated with survival can be defined. When they are taken into account, survival varies between 12.6 and 0.15%.

An evaluation of post-resuscitation care as a possible explanation of a difference in survival after out-of-hospital cardiac arrest

BACKGROUND

A recently published study has shown that survival after out-of-hospital cardiac arrest (OHCA) in Göteborg is almost three times higher than in Stockholm. The aim of this study was to investigate whether in-hospital factors were associated with outcome in terms of survival.

METHODS

All patients suffering from OHCA in Stockholm and Göteborg between January 1, 2000 and June 30, 2002 were included. The two groups were compared with reference to patient characteristics, medical history, pre-hospital and hospital course (including in-hospital investigations and interventions) and mortality. All medical charts from patients admitted alive to the different hospitals were studied. Data from the Swedish National Register of Deaths regarding long-term survival were analysed. Pre-hospital data were collected from the Swedish Ambulance Cardiac Arrest Register.

RESULTS

In all, 1542 OHCA in Stockholm and 546 in Göteborg were registered during the 30-month study period. In Göteborg, 28% (153 patients) were admitted alive to the two major hospitals whereas in Stockholm 16% (253 patients) were admitted alive to the seven major hospitals (p<0.0001). On admission to the emergency rooms, a larger proportion of patients in Stockholm was unconscious (p=0.006), received assisted breathing (p=0.008) and ongoing CPR (p=0.0002). Patient demography, medical history, in-hospital investigations and interventions and in-hospital mortality (78% in Göteborg, 80% in Stockholm) did not differ between the two groups. Various pre-hospital time intervals were significantly longer in Stockholm than in Göteborg. Total survival to discharge after OHCA was 3.3% in Stockholm and 6.1% in Göteborg (p=0.01).

CONCLUSION

An almost 2-fold difference in survival after OHCA between Stockholm and Göteborg appears to be associated with pre-hospital factors only (predominantly in form of prolonged intervals in Stockholm), rather than with in-hospital factors or patient characteristics.

Characteristics and outcome amongst young adults suffering from out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation is attempted

OBJECTIVES

Amongst patients suffering from out-of-hospital cardiac arrest, young adults represent a minority. However, these victims suffer from the catastrophe when they are in a very active phase of life and have a long life expectancy. This survey aims to describe young adults in Sweden who suffer from out-of-hospital cardiac arrest and in whom cardiopulmonary resuscitation (CPR) is attempted in terms of characteristics and outcome.

DESIGN

Prospective and descriptive design.

SUBJECTS AND METHODS

Young adults (18-35 years) who suffered from out-of-hospital cardiac arrest in whom CPR was attempted and who were included in the Swedish Cardiac Arrest Registry between 1990 and 2004.

MAIN OUTCOME MEASURES

Survival to 1 month.

RESULTS

In all, 1105 young adults (3.1% of all the patients in the registry) were included, of which 29% were females, 51% were nonwitnessed and 15% had a cardiac aetiology. Only 17% were found in ventricular fibrillation, 53% received bystander CPR. The overall survival to 1 month was 6.3%. High survival was found amongst patients found in ventricular fibrillation (20.8%) and those with a cardiac aetiology (14.8%). Ventricular fibrillation at the arrival of the rescue team remained an independent predictor of an increased chance of survival (odds ratio: 7.43; 95% confidence interval: 3.44-16.65).

CONCLUSION

Amongst young adults suffering from out-of-hospital cardiac arrest and in whom CPR was attempted, a minority survived to 1 month. Subgroups with a higher survival could be defined (patients found in ventricular fibrillation and patients in whom there was a cardiac aetiology). However, only one independent predictor of an increased chance of survival could be demonstrated, i.e. ventricular fibrillation at the arrival of the rescue team.

Association between interval between call for ambulance and return of spontaneous circulation and survival in out-of-hospital cardiac arrest

AIM

To describe the association between the interval between the call for ambulance and return of spontaneous circulation (ROSC) and survival in out-of-hospital cardiac arrest.

PATIENTS

All patients suffering an out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation (CPR) was started, included in the Swedish Cardiac Arrest Registry (SCAR) for whom information about the time of calling for an ambulance and the time of ROSC was available.

RESULTS

Among 26,192 patients who were included in SCAR and were not witnessed by the ambulance crew, information about the time of call for an ambulance and the time of ROSC was available in 4847 patients (19%). There was a very strong relationship between the interval between call for an ambulance and ROSC and survival to one month. If the interval was less than or equal to 5 min, 47% survived to one month. If the interval exceeded 30 min, only 5% (n = 35) survived to one month. The vast majority of the latter survivors had a shockable rhythm either on admission of the rescue team or at some time during resuscitation.

CONCLUSION

Among patients who have ROSC after an out-of-hospital cardiac arrest, there is a very strong association between the interval between the call for ambulance and ROSC and survival to one month. However, even if this delay is very long (> 30 min after calling for an ambulance), a small percentage will ultimately survive; they are mainly patients who at some time during resuscitation have a shockable rhythm. The overall percentage of patients for whom CPR continued for more than 30 min who are alive one month later can be assumed to be extremely low.

Major differences in 1-month survival between hospitals in Sweden among initial survivors of out-of-hospital cardiac arrest

AIM

To explore the rate of survival to hospital discharge among patients who were brought to hospital alive after an out-of-hospital cardiac arrest in different hospitals in Sweden.

PATIENTS AND METHODS

All patients who had suffered an out-of-hospital cardiac arrest which was not witnessed by the ambulance crew, in whom cardiopulmonary resuscitation (CPR) was started and who had a palpable pulse on admission to hospital were evaluated for inclusion. Each participating ambulance organisation and its corresponding hospital(s) required at least 50 patients fulfilling these criteria.

RESULTS

Three thousand eight hundred and fifty three patients who were brought to hospital by 21 different ambulance organisations fulfilled the inclusion criteria. The number of patients rescued by each ambulance organisation varied between 55 and 900. The survival rate, defined as alive 1 month after cardiac arrest, varied from 14% to 42%. When correcting for dissimilarities in characteristics and factors of the resuscitation, the adjusted odds ratio for survival to 1 month among patients brought to hospital alive in the three ambulance organisations with the highest survival versus the three with the lowest survival was 2.63 (95% CI: 1.77-3.88).

CONCLUSION

There is a marked variability between hospitals in the rate of 1-month survival among patients who were alive on hospital admission after an out-of-hospital cardiac arrest. One possible contributory factor is the standard of post-resuscitation care.

Characteristics and outcome among children suffering from out of hospital cardiac arrest in Sweden

AIM

To evaluate the characteristics, outcome and prognostic factors among children suffering from out of hospital cardiac arrest in Sweden.

METHODS

Patients aged below 18 years suffering from out of hospital cardiac arrest which were not crew witnessed and included in the Swedish cardiac arrest registry were included in the survey. This survey included the period 1990-2001 and 60 ambulance organisations covering 85% of the Swedish population (8 million inhabitants).

RESULTS

In all 457 children participated in the survey of which 32% were bystander witnessed and 68% received bystander CPR. Ventricular fibrillation was found in 6% of the cases. The overall survival to 1 month was 4%. The aetiology was sudden infant death syndrome in 34% and cardiac in 11%. When in a multivariate analysis considering age, sex, witnessed status, bystander CPR, initial rhythm, aetiology and the interval between call for, and arrival of, the ambulance and place of arrest only one appeared as an independent predictor of an increased chance of surviving cardiac arrest occurring outside home (adjusted odds ratio 8.7; 95% CL 2.2-58.1).

CONCLUSION

Among children suffering from out of hospital cardiac arrest in Sweden that were not crew witnessed, the overall survival is low (4%). The chance of survival appears to be markedly increased if the arrest occurs outside the patients home compared with at home. No other strong predictors for an increased chance of survival could be demonstrated.

Can we define patients with no chance of survival after out-of-hospital cardiac arrest?

OBJECTIVE

To evaluate whether subgroups of patients with no chance of survival can be defined among patients with out-of-hospital cardiac arrest.

PATIENTS

Patients in the Swedish cardiac arrest registry who fulfilled the following criteria were surveyed: cardiopulmonary resuscitation (CPR) was attempted; the arrest was not crew witnessed; and patients were found in a non-shockable rhythm.

SETTING

Various ambulance organisations in Sweden.

DESIGN

Prospective observational study.

RESULTS

Among the 16,712 patients who fulfilled the inclusion criteria, the following factors were independently associated with a lower chance of survival one month after cardiac arrest: no bystander CPR; non-witnessed cardiac arrest; cardiac arrest occurring at home; increasing interval between call for and arrival of the ambulance; and increasing age. When these factors were considered simultaneously two groups with no survivors were defined. In both groups patients were found in a non-shockable rhythm, no bystander CPR was attempted, the arrest was non-witnessed, the arrest took place at home. In one group the interval between call for and arrival of ambulance exceeded 12 minutes. In the other group patients were older than 80 years and the interval between call for and arrival of the ambulance exceeded eight minutes.

CONCLUSION

Among patients who had an out-of-hospital cardiac arrest and were found in a non-shockable rhythm the following factors were associated with a low chance of survival: no bystander CPR, non-witnessed cardiac arrest, the arrest took place at home, increasing interval between call for and arrival of ambulance, and increasing age. When these factors were considered simultaneously, groups with no survivors could be defined. In such groups the ambulance crew may refrain from starting CPR.

Nineteen years' experience of out-of-hospital cardiac arrest in Gothenburg--reported in Utstein style

OBJECTIVE

To describe the outcome in the Utstein style for out of hospital cardiac arrest in Gothenburg, over a period of 19 years.

METHODS

All consecutive cases of cardiac arrest between 1980 and 1999 in which the emergency medical service (EMS) system responded and attempted resuscitation were reported and followed up for 1 year.

RESULTS

In all, there were 5270 attempts. 3871 (73%) of which were regarded as being of a cardiac aetiology. In these cases, information on witnessed status was missing in 782 cases (20%). Of the remaining 3089 cases, 2066 (67%) were bystander witnessed, 791 (26%) were unwitnessed and 232 (8%) crew witnessed. The median interval between a call for the ambulance and the arrival of the first ambulance was 5 min. Thirteen percent of the bystander-witnessed cases were discharged from hospital. Of the unwitnessed cases, only 2% were discharged from hospital, whereas 22% of the crew-witnessed cases were discharged. Of the patients with a bystander-witnessed cardiac arrest of a cardiac aetiology found in ventricular fibrillation (VF), 20% were discharged from hospital.

CONCLUSION

In this large Utstein style study of out of hospital cardiac arrest stretching over almost 19 years, we report high survival rates both for patients suffering a bystander-witnessed cardiac arrest, and for the subgroup suffering a bystander-witnessed cardiac arrest with VF as the first recorded rhythm. These high survival rates can in part be explained by the short time intervals from calls being received by the emergency dispatch centre (EDC) to the arrival of the emergency medical service at the scene.

Factors associated with survival to hospital discharge among patients hospitalised alive after out of hospital cardiac arrest: change in outcome over 20 years in the community of Göteborg, Sweden

OBJECTIVE

To describe the change in survival and factors associated with survival during a 20 year period among patients suffering from out of hospital cardiac arrest and being hospitalised alive.

PATIENTS

All patients hospitalised alive in the community of Göteborg after out of hospital cardiac arrest between 1 October 1980 and 1 October 2000 were included.

METHODS

Patient data were prospectively computerised with regard to factors at resuscitation. Data on medical history and hospitalisation were retrospectively recorded. Patients were divided into two groups (the first and second 10 year periods).

SETTING

Community of Göteborg, Sweden.

RESULTS

5505 patients suffered from cardiac arrest during the time of the survey. Among them 1310 patients (24%) were hospitalised alive. Survival (discharged alive) was 37.5% during the first part and 35.1% during the second part (NS). The following were independent predictors of an increased chance of survival: ventricular fibrillation/tachycardia as the first recorded rhythm (odds ratio (OR) 3.46, 95% confidence interval (CI) 2.36 to 5.07); witnessed arrest (OR 2.50, 95% CI 1.52 to 4.10); bystander initiated cardiopulmonary resuscitation (OR 2.00, 95% CI 1.42 to 2.80); the patient being conscious on admission to hospital (OR 6.43, 95% CI 3.61 to 11.45); sinus rhythm on admission to hospital (OR 1.53, 95% CI 1.12 to 2.10); and treatment with lidocaine in the emergency department (OR 1.64, 95% CI 1.16 to 2.31). The following were independent predictors of a low chance of survival: age > 70 years (median) (OR 0.65, 95% CI 0.47 to 0.88); atropine required in the emergency department (OR 0.35, 95% CI 0.16 to 0.75); and chronic treatment with diuretics before hospital admission (OR 0.59, 95% CI 0.43 to 0.81).

CONCLUSION

There was no improvement in survival over time among initial survivors of out of hospital cardiac arrest during a 20 year period. Major indicators for an increased chance of survival were initial ventricular fibrillation/tachycardia, bystander cardiopulmonary resuscitation, arrest being witnessed, and the patient being conscious on admission. Major indicators for a lower chance were high age, requirement for atropine in the emergency department, and chronic treatment with diuretics before cardiac arrest.

Characteristics and outcome among patients having out of hospital cardiac arrest at home compared with elsewhere

OBJECTIVE

To describe the characteristics and outcome of patients who have a cardiac arrest at home compared with elsewhere out of hospital.

PATIENTS

Subjects were patients included in the Swedish cardiac arrest registry between 1990 and 1999. The registry covers about 60% of all ambulance organisations in Sweden.

METHODS

The study sample comprised patients reached by the ambulance crew and in whom resuscitation was attempted out of hospital. There was no age limit. Crew witnessed cases were excluded. The patients were divided into two groups: cardiac arrest at home and cardiac arrest elsewhere.

RESULTS

Among a study population of 24 630 patients the event took place at home in 16 150 (65.5%). Those in whom the arrest took place at home differed from the remainder in that they were older, were more often women, less often had a witnessed cardiac arrest, were less often exposed to bystander cardiopulmonary resuscitation (CPR), were less often found in ventricular fibrillation, and had a longer interval between collapse and call for ambulance, arrival of ambulance, start of CPR, and first defibrillation. Of patients in whom the arrest took place at home, 11.3% were admitted to hospital alive, v 19.4% in the elsewhere group (p < 0.0001); corresponding figures for survival after one month were 1.7% v 6.2% (p < 0.0001). The adjusted odds ratio for survival after one month (at home v not at home; considering age, sex, initial arrhythmia, bystander CPR, aetiology, and whether the arrest was witnessed) was 0.40 (95% confidence interval 0.33 to 0.49; p < 0.0001).

CONCLUSIONS

Sixty five per cent of out of hospital cardiac arrests in Sweden occur at home. The patients differed greatly from those with out of hospital cardiac arrests elsewhere, and fewer than 2% were alive after one month. Having an arrest at home was a strong independent predictor of adverse outcome. Further research is needed to identify the reasons for this.

The epidemiology of out-of-hospital 'sudden' cardiac arrest

It is difficult to assemble data from an out-of-hospital cardiac arrest since there is often lack of objective information. The true incidence of sudden cardiac death out-of-hospital is not known since far from all of these patients are attended by emergency medical services. The incidence of out-of-hospital cardiac arrest increases with age and is more common among men. Among patients who die, the probability of having a fatal event outside hospital decreases with age; i. e. younger patients tend to more often die unexpectedly and outside hospital. Among the different initial arrhythmias, ventricular fibrillation is the most common among patients with cardiac aetiology. The true distribution of initial arrhythmias is not known since several minutes most often elapse between collapse and rhythm assessment. Most patients with out-of-hospital cardiac arrest have a cardiac aetiology. Out-of-hospital cardiac arrests most frequently occur in the patient's home, but the prognosis is shown to be better when they occur in a public place. Witnessed arrest, ventricular fibrillation as initial arrhythmia and cardiopulmonary resuscitation are important predictors for immediate survival. In the long-term perspective, cardiac arrest in connection with acute myocardial infarction, high left ventricular ejection fraction, moderate age, absence of other heart failure signs and no history of myocardial infarction promotes better prognosis. Still there is much to learn about time trends, the influence of patient characteristics, comorbidity and hospital treatment among patients with prehospital cardiac arrest.

Long-term mortality among patients discharged alive after out-of-hospital cardiac arrest does not differ markedly compared with that of myocardial infarct patients without out-of-hospital cardiac arrest

The aim of our research was to study the long-term prognosis among patients discharged alive after an out-of-hospital cardiac arrest (OHCA) in comparison with patients discharged alive after acute myocardial infarction (AMI) without OHCA, and also to study the long-term influence of AMI in connection with OHCA. Our research was conducted in the municipality of Göteborg. We retrospectively studied patients discharged from hospital 1990-91 after an OHCA of cardiac aetiology and patients discharged after an AMI without prehospital cardiac arrest. During 1980-98, we studied all patients discharged alive after OHCA of cardiac aetiology, divided into groups of precipitating AMI and no AMI. The study includes 48 patients discharged alive after an OHCA 1990-91, 30 (62%) of whom had a simultaneous AMI and 1425 patients with an AMI without OHCA. Compared with AMI survivors, survivors of an OHCA of cardiac origin were younger but had more frequently a history of congestive heart failure. Their mortality rate during the subsequent 5 years was 46%, compared with 40% among survivors of an AMI (NS). The 5-year mortality rate among patients with an OHCA precipitated by an AMI was 40%. When correcting for differences at baseline, the adjusted risk ratio for death among patients with an OHCA of cardiac origin was 1.2 (95% CI 0.8-1.8) compared with patients with an uncomplicated AMI. During 1980-98, 215 patients were judged as having an OHCA precipitated by an AMI and 115 patients had an OHCA of cardiac aetiology but no simultaneous AMI. Five-year mortality was 54% and 50% respectively (NS). It is concluded that survivors of an OHCA of cardiac origin differed from survivors of an uncomplicated AMI in that they were younger and more frequently had a history of cardiovascular disease. Their 5-year mortality after discharge was similar to that of survivors of an AMI without a prehospital cardiac arrest, even after adjusting for differences at baseline.

Factors affecting short- and long-term prognosis among 1069 patients with out-of-hospital cardiac arrest and pulseless electrical activity

AIMS

To describe the epidemiology, resuscitation factors and prognosis among a consecutive population of patients suffering from out-of-hospital cardiac arrest (OHCA) where pulseless electrical activity (PEA) was the first arrhythmia recorded on emergency medical services (EMS) arrival.

METHODS

Analysis of data collected prospectively on all patients regardless of age succumbing to OHCA during 1980-1997 in the community of Gothenburg where EMS initiated resuscitative measures.

RESULTS

4662 patients with OHCA were attended by the EMS during the study period. Of these, 1069 (23%) were judged as having PEA as the first recorded arrhythmia; 158 (15%) of these were admitted alive to hospital and 26 (2.4%) were discharged alive. Survivors to discharge had a significantly larger share of bystander cardiopulmonary resuscitation (CPR) (28 vs. 8%, P=0.008), significantly higher levels of consciousness (8% awake vs. 0%, P<0.001) and higher median systolic blood pressure (145 vs. 106 mmHg, P<0.001) on arrival at hospital. No patient with unwitnessed cardiac arrest and PEA over 80 years old survived.

CONCLUSION

Survival among patients suffering from OHCA and PEA is poor, especially among the elderly unwitnessed cases and those who do not receive bystander CPR. The latter seems to be of utmost importance among these patients.

Can we define patients with no and those with some chance of survival when found in asystole out of hospital?

We describe the epidemiology, prognosis, and circumstances at resuscitation among a consecutive population of patients with out-of-hospital cardiac arrest (OHCA) with asystole as the arrhythmia first recorded by the Emergency Medical Service (EMS), and identify factors associated with survival. We included all patients in the municipality of Göteborg, regardless of age and etiology, who experienced an OHCA between 1981 and 1997. There were a total of 4,662 cardiac arrests attended by the EMS during the study period. Of these, 1,635 (35%) were judged as having asystole as the first-recorded arrhythmia: 156 of these patients (10%) were admitted alive to hospital, and 32 (2%) were discharged alive. Survivors were younger (median age 58 vs 68 years) and had a witnessed cardiac arrest more often than nonsurvivors (78% vs 50%). Survivors also had shorter intervals from collapse to arrival of ambulance (3.5 vs 6 minutes) and the mobile coronary care unit (MCCU) (5 vs 10 min), and they received atropine less often on scene. There were also a greater proportion of survivors with noncardiac etiologies of cardiac arrest (48% vs 27%). Survivors to discharge also displayed higher degrees of consciousness on arrival to the emergency department in comparison to nonsurvivors. Multivariate analysis among all patients with asystole indicated age (p = 0.01) and witnessed arrest (p = 0.03) as independent predictors of an increased chance of survival. Multivariate analysis among witnessed arrests indicated short time to arrival of the MCCU (p < 0.001) and no treatment with atropine (p = 0.05) as independent predictors of survival. Fifty-five percent of patients discharged alive had none or small neurologic deficits (cerebral performance categories 1 or 2). No patients > 70 years old with unwitnessed arrests (n = 211) survived to discharge.

Experiences from treatment of out-of-hospital cardiac arrest during 17 years in Göteborg

AIMS

To describe changes in different factors at resuscitation and survival in a 17-year survey of patients suffering from out-of-hospital cardiac arrest.

METHOD

The investigation was carried out in the community of Göteborg with 450 000 inhabitants during 1981-1997 on all patients suffering out-of-hospital cardiac arrest in whom resuscitation was attempted.

RESULTS

The number of cases per year, the proportion of witnessed arrests and the proportion of arrests of cardiac aetiology remained similar over time. There was an increase in median age from 68 to 73 years (P<0.0001), in the proportion of females from 27% to 33% (P=0.035) and in the proportion of patients receiving bystander cardiopulmonary resuscitation from 14% to 28% (P<0.0001) with time. There was a shortening of the median interval from collapse until defibrillation from 9 min to 6 min (P<0.0001) over time but a decrease in the occurrence of ventricular fibrillation as the initially recorded arrhythmia from 39% to 32% (P=0.022). There was an increase in the proportion of patients having a bystander witnessed cardiac arrest of cardiac aetiology being hospitalized alive from 32% to 45% (P<0. 0001 for change over time). The proportion of patients discharged alive from hospital increased from 16% to 29% until 1993, but thereafter decreased to 13% in 1997 (P=0.002 for change over time).

CONCLUSION

In a survey covering 17 years of resuscitation of out-of-hospital cardiac arrest patients we found that the occurrence of ventricular fibrillation as the initially recorded arrhythmia decreased. There was an increase in age, in the proportion of females and in the use of bystander cardiopulmonary resuscitation. The interval between collapse and defibrillation was shortened. Survival changed over time with an increase until 1993 but with a decrease thereafter.

Is hospital care of major importance for outcome after out-of-hospital cardiac arrest? Experience acquired from patients with out-of-hospital cardiac arrest resuscitated by the same Emergency Medical Service and admitted to one of two hospitals over a 16-year period in the municipality of Göteborg

AIM

To describe patient characteristics, hospital investigations and interventions and early mortality among patients being hospitalized after out-of-hospital cardiac arrest in two hospitals.

SETTING

Municipality of Göteborg, Sweden.

PATIENTS

All patients suffering an out-of-hospital cardiac arrest who were successfully resuscitated and admitted to hospital between 1 October 1980 and 31 December 1996. All patients were resuscitated by the same Emergency Medical Service and admitted alive to one of the two city hospitals in Göteborg.

RESULTS

Of 579 patients admitted to Sahlgrenska Hospital, 253 (44%) were discharged alive and of 459 patients admitted to Ostra Hospital, 152 (33%) were discharged alive (P < 0.001). More patients in Sahlgrenska Hospital were still receiving cardiopulmonary resuscitation (CPR) treatment (P = 0.03), but patients in Ostra had a lower systolic blood pressure and higher heart rate on admission. A larger percentage of patients admitted to Sahlgrenska Hospital underwent coronary angiography (P < 0.001), electrophysiological testing (P < 0.001), Holter recording (P < 0.001), echocardiography (P = 0.004), percutaneous transluminal coronary angioplasty (PTCA, P = 0.009), implantation of automatic implantable cardioverter defibrillator (AICD, P = 0.03) and exercise stress tests (P = 0.003). Inhabitants in the catchment area of Ostra Hospital had a less favourable socio-economic profile.

CONCLUSION

Survival after out-of-hospital cardiac arrest may be affected by the course of hospital management. Other variables that might influence survival are socio-economic factors and cardiorespiratory status on admission to hospital. Further investigation is called for as more patients are being hospitalised alive after out-of-hospital cardiac arrest.

Outcomes of patients hospitalized after out-of-hospital cardiac arrest in relation to sex

OBJECTIVE

To describe characteristics and outcomes of patients hospitalized after out-of-hospital cardiac arrest in relation to sex.

PATIENTS

All patients in the community of Göteborg who between 1980 and 1996 suffered out-of-hospital cardiac arrest and were hospitalized alive.

METHODS

We calculated age-adjusted P values.

RESULTS

In all 1038 patients were hospitalized alive of whom 29% were women. Women differed from men by being older and there being lower prevalences of previous acute myocardial infarction (AMI) and smoking and a higher prevalence of bronchial asthma among them. They had less commonly received cardio-pulmonary resuscitation (CPR) from bystanders (16 versus 25% of cases; P = 0.002) and were less commonly found to be in ventricular fibrillation when the ambulance crew arrived (55 versus 73% of cases; P < 0.0001). They were less commonly judged to have a cardiac etiology behind the arrest (87 versus 92% of cases; P = 0.016). Of women 31.3% could be discharged alive from hospital, compared with 41.8% of men (P = 0.001). While they were in hospital, women were less commonly subjected to exercise tests, coronary angiography, and coronary artery bypass grafting.

CONCLUSION

Among patients who suffered out-of-hospital cardiac arrest and were hospitalized alive, women had less commonly received CPR from bystanders, were less commonly found in ventricular fibrillation, less commonly underwent coronary angiography and coronary artery bypass grafting and had a lower survival rate than did men.

There is a difference in characteristics and outcome between women and men who suffer out of hospital cardiac arrest

OBJECTIVE

To evaluate whether there is a difference in characteristics and outcome in relation to gender among patients who suffer out of hospital cardiac arrest.

DESIGN

Observational study.

SETTING

The community of Göteborg.

PATIENTS

All patients in the community of Göteborg who suffered out of hospital cardiac arrest between 1980 and 1996, and in whom cardiopulmonary resuscitation (CPR) was initiated.

MAIN OUTCOME MEASURES

Factors at resuscitation and the proportion of patients being hospitalized and discharged from hospital. P values were corrected for age.

RESULTS

The women were older than the men (median of 73 vs. 69 years; P < 0.0001), they received bystander-CPR less frequently (11 vs. 15%; P = 0.003), they were found in ongoing ventricular fibrillation less frequently (28 vs. 44%; P < 0.0001), and their arrests were judged to be of cardiac origin less frequently. In a multivariate analysis considering age, gender, arrest being due to a cardiac etiology, initial arrhythmia and by-stander initiated CPR, female gender appeared as an independent predictor for patients being brought to hospital alive (odds ratio 1.37; P = 0.001) but not for patients being discharged from hospital.

CONCLUSION

Among patients who suffer out of hospital cardiac arrest with attempted CPR women differ from men being older, receive bystander CPR less frequently, have a cardiac etiology less frequently and are found in ventricular fibrillation less frequently. Finally female gender is associated with an increased chance of arriving at hospital alive.

Quantitative evaluation of a comprehensive motion, resolution, and attenuation correction program: initial experience

BACKGROUND

Tomographic myocardial imaging is widely used in the diagnosis and evaluation of patients with coronary artery disease. However, its specificity remains suboptimal because of attenuation, resolution, and motion artifacts. The purpose of this study was to optimize and assess the value of attenuation, blur, and motion correction of myocardial single photon emission computed tomographic data.

METHODS AND RESULTS

Forty-seven studies were selected for analysis to provide 3 patient groups. Group A consisted of 18 patients with a low likelihood of coronary artery disease who were used to construct a quantitative normal database and assess changes in the normal bull's-eye produced by filtering and by attenuation correction. Group B consisted of 13 patients with a high probability of normal results, and group C consisted of 16 patients with coronary artery disease defined on angiography. The effects of attenuation correction, especially in conjunction with RESTORE (a depth-dependent deblurring filter), have been quantitated. Analysis indicates a trend to improved sensitivity and specificity for detecting individual vessel disease in this retrospective study. The motion correction program was successfully applied to 93% of patients but detected significant motion requiring correction in only 11 (24%) patients.

CONCLUSION

This preliminary retrospective study indicates a potential for improved myocardial single photon emission computed tomography imaging with the use of attenuation and motion correction together with a restorative deblurring filter. Confirmation by a multicenter study and larger patient numbers remain necessary to assess fully the prospective value of the technique.

Effect of training on insulin secretion from single pancreatic beta cells

The objective of this study was to determine whether insulin secretion from single pancreatic beta cells is reduced by endurance training. Male Sprague Dawley rats either trained (T, N = 9) for 11 wk on a rodent treadmill, remained sedentary, and were fed ad libitum (S, N = 8) or remained sedentary and were food restricted (pair fed, PF, N = 8) so that final body weights were similar to T. After training, T had significantly higher red gastrocnemius muscle citrate synthase activity compared with S and PF. In vivo insulin secretion was lower in T (4.6 +/- 1.4 ng.ml-1, mean +/- SEM of 70' + 90' concentrations during a hyperglycemic glucose clamp) when compared with S, 8.1 +/- 1.6 and PF, 9.7 +/- 1.7 ng.ml-1. In vitro insulin secretion from single beta cells was measured using the cell blot assay (Kendall and Hymer, Endocrinology, 121:2260-2262, 1987) and T, had lower secretion 2.6 +/- 1.4 pg.cell-1 when compared (P less than 0.05) with S, 6.7 +/- 0.6, but not lower than PF, 4.1 +/- 1.7 pg.cell-1. These data suggest that some of the training-induced reduction in insulin secretory response to glucose may be attributable to changes within the beta cell itself.