Cost-effectiveness of population screening for atrial fibrillation: the STROKESTOP study.

AIMS: Previous studies on the cost-effectiveness of screening for atrial fibrillation (AF) are based on assumptions of long-term clinical effects. The STROKESTOP study, which randomised 27 975 persons aged 75/76 years into a screening invitation group and a control group, has a median follow-up time of 6.9 years. The aim of this study was to estimate the cost-effectiveness of population-based screening for AF using clinical outcomes. METHODS AND RESULTS: The analysis is based on a Markov cohort model. The prevalence of AF, the use of oral anticoagulation, clinical event data, and all-cause mortality were taken from the STROKESTOP study. The cost for clinical events, age-specific utilities, utility decrement due to stroke, and stroke death was taken from the literature. Uncertainty in the model was considered in a probabilistic sensitivity analysis. Per 1000 individuals invited to the screening, there were 77 gained life years and 65 gained quality-adjusted life years. The incremental cost was €1.77 million lower in the screening invitation group. Gained quality-adjusted life years to a lower cost means that the screening strategy was dominant. The result from 10 000 Monte Carlo simulations showed that the AF screening strategy was cost-effective in 99.2% and cost-saving in 92.7% of the simulations. In the base-case scenario, screening of 1000 individuals resulted in 10.6 [95% confidence interval (CI): -22.5 to 1.4] fewer strokes (8.4 ischaemic and 2.2 haemorrhagic strokes), 1.0 (95% CI: -1.9 to 4.1) more cases of systemic embolism, and 2.9 (95% CI: -18.2 to 13.1) fewer bleedings associated with hospitalization. CONCLUSION: Based on the STROKESTOP study, this analysis shows that a broad AF screening strategy in an elderly population is cost-effective. Efforts should be made to increase screening participation.

Atrial Fibrillation and Dementia: A Report From the AF-SCREEN International Collaboration.

Growing evidence suggests a consistent association between atrial fibrillation (AF) and cognitive impairment and dementia that is independent of clinical stroke. This report from the AF-SCREEN International Collaboration summarizes the evidence linking AF to cognitive impairment and dementia. It provides guidance on the investigation and management of dementia in patients with AF on the basis of best available evidence. The document also addresses suspected pathophysiologic mechanisms and identifies knowledge gaps for future research. Whereas AF and dementia share numerous risk factors, the association appears to be independent of these variables. Nevertheless, the evidence remains inconclusive regarding a direct causal effect. Several pathophysiologic mechanisms have been proposed, some of which are potentially amenable to early intervention, including cerebral microinfarction, AF-related cerebral hypoperfusion, inflammation, microhemorrhage, brain atrophy, and systemic atherosclerotic vascular disease. The mitigating role of oral anticoagulation in specific subgroups (eg, low stroke risk, short duration or silent AF, after successful AF ablation, or atrial cardiopathy) and the effect of rhythm versus rate control strategies remain unknown. Likewise, screening for AF (in cognitively normal or cognitively impaired patients) and screening for cognitive impairment in patients with AF are debated. The pathophysiology of dementia and therapeutic strategies to reduce cognitive impairment warrant further investigation in individuals with AF. Cognition should be evaluated in future AF studies and integrated with patient-specific outcome priorities and patient preferences. Further large-scale prospective studies and randomized trials are needed to establish whether AF is a risk factor for cognitive impairment, to investigate strategies to prevent dementia, and to determine whether screening for unknown AF followed by targeted therapy might prevent or reduce cognitive impairment and dementia.

Prognostic implication of premature ventricular contractions in patients without structural heart disease.

AIMS: Premature ventricular contractions (PVCs) are a common form of arrhythmia associated with an unfavourable prognosis in patients with structural heart disease. However, the prognostic significance in absence of heart disease is debated. With this study, we aim to investigate whether subjects with PVC, without structural heart disease, have a worse prognosis than the general population. METHODS AND RESULTS: Patients evaluated for PVC at a secondary care centre in Stockholm County from January 2010 to December 2016 were identified. We included patients without history of previous heart disease who had undergone echocardiography and exercise test with normal findings. Based on sex and age, we matched the PVC cohort to a four times bigger control group from the general population and compared the outcome in terms of mortality and cardiovascular morbidity during a median follow-up time of 5.2 years. We included 820 patients and 3,264 controls. Based on a non-inferiority analysis, the PVC group did not have a higher mortality than the control group (0.44, CI 0.27-0.72). Sensitivity analysis with propensity score matching confirmed this result. CONCLUSIONS: PVC patients, who after thorough evaluation showed no signs of structural heart disease, did not have a worse prognosis when compared to an age- and sex- control group based on the general population.

Prognostic impact of morphology and duration of premature ventricular contractions in a population without structural heart disease.

BACKGROUND: Premature ventricular contractions (PVCs) are a common form of arrhythmia associated with an unfavorable prognosis in patients with structural heart disease. It is unclear whether PVCs site of origin and QRS-width has a prognostic significance in patients without structural heart disease. The aim of this study was to assess the prognostic importance of PVCs morphology and duration in this patient group. METHODS: We included 511 consecutive patients without a history of previous heart disease. They were examined with echocardiography and exercise test with normal findings. We categorized the PVCs from a 12 lead ECG according to morphology and width of the QRS-complex and analyzed the outcome in terms of a composite endpoint of total mortality and cardiovascular morbidity. RESULTS: During a median follow-up time of 5.3 years, 19 patients (3.5%) died and 61 (11.3%) met the composite outcome. Patients with PVCs originating from the outflow tracts had a significantly lower risk for the composite outcome compared to patients with non-OT-PVCs. Similarly, patients with PVC originating from the right ventricle had a better outcome than patients with left ventricular PCVs. No difference in outcome depending on QRS-width during PVCs was noticed. CONCLUSION: In our cohort of consecutively included PVC patients without structural heart disease PVCs from the outflow tracts were associated with a better prognostic outcome than non-OT PVCs; the same was true for right ventricular PVCs when compared to left ventricular ones. The classification of the origin of the PVCs was based on 12-lead ECG morphology. QRS-width during PVC did not seem to have prognostic significance.

Clinical outcomes in systematic screening for atrial fibrillation (STROKESTOP): a multicentre, parallel group, unmasked, randomised controlled trial.

BACKGROUND: Atrial fibrillation is a leading cause of ischaemic stroke. Early detection of atrial fibrillation can enable anticoagulant therapy to reduce ischaemic stroke and mortality. In this randomised study in an older population, we aimed to assess whether systematic screening for atrial fibrillation could reduce mortality and morbidity compared with no screening. METHODS: STROKESTOP was a multicentre, parallel group, unmasked, randomised controlled trial done in Halland and Stockholm in Sweden. All 75-76-year-olds residing in these two regions were randomly assigned (1:1) to be invited to screening for atrial fibrillation or to a control group. Participants attended local screening centres and those without a history of atrial fibrillation were asked to register intermittent electrocardiograms (ECGs) for 14 days. Treatment with oral anticoagulants was offered if atrial fibrillation was detected or untreated. All randomly assigned individuals were followed up in the intention-to-treat analysis for a minimum of 5 years for the primary combined endpoint of ischaemic or haemorrhagic stroke, systemic embolism, bleeding leading to hospitalisation, and all-cause death. This trial is registered with ClinicalTrials.gov, NCT01593553. FINDINGS: From March 1, 2012, to May 28, 2014, 28 768 individuals were assessed for eligibility and randomly assigned to be invited to screening (n=14 387) or the control group (n=14 381). 408 individuals were excluded from the intervention group and 385 were excluded from the control group due to death or migration before invitation. There was no loss to follow-up. Of those invited to screening, 7165 (51·3%) of 13 979 participated. After a median follow-up of 6·9 years (IQR 6·5-7·2), significantly fewer primary endpoint events occurred in the intervention group (4456 [31·9%] of 13 979; 5·45 events per 100 years [95% CI 5·52-5·61]) than in the control group (4616 [33·0%] of 13 996; 5·68 events per 100 years [5·52-5·85]; hazard ratio 0·96 [95% CI 0·92-1·00]; p=0·045). INTERPRETATION: Screening for atrial fibrillation showed a small net benefit compared with standard of care, indicating that screening is safe and beneficial in older populations. FUNDING: Stockholm County Council, the Swedish Heart & Lung Foundation, King Gustav V and Queen Victoria's Freemasons' Foundation, the Klebergska Foundation, the Tornspiran Foundation, the Scientific Council of Halland Region, the Southern Regional Healthcare Committee, the Swedish Stroke Fund, Carl Bennet AB, Boehringer Ingelheim, Bayer, and Bristol Myers Squibb-Pfizer.

Cost-effectiveness of screening for atrial fibrillation in a single primary care center at a 3-year follow-up.

OBJECTIVES: The aim of this study was to estimate the cost-effectiveness of intermittent electrocardiogram (ECG) screening for atrial fibrillation (AF) among 70-74-year old individuals in primary care. We also aimed to assess adherence to anticoagulants, severe bleeding, stroke and mortality among screening-detected AF cases at three-year follow-up. METHODS: A post hoc analysis based on a cross-sectional screening study for AF among 70-74-year old patients, who were registered at a single primary care center, was followed for three years for mortality. Data about adherence to anticoagulants, incidence of stroke and severe bleeding among screening-detected AF cases, were collected from patient's records. Markov model and Monte Carlo simulation were used to assess the cost-effectiveness of the screening program. RESULTS: The mortality rate among screening-detected AF cases (n = 16) did not differ compared to the 274 individuals with no AF (hazard ratio 0.86, CI 0.12-6.44). Adherence to anticoagulants was 92%. There was no stroke or severe bleeding. The incremental cost-effectiveness ratio of screening versus no screening was EUR 2389/quality-adjusted life year (QALY) gained. The screening showed a 99% probability of being cost-effective compared to no screening at a willingness-to-pay threshold of EUR 20,000 per QALY. CONCLUSION: Screening for AF among 70-74-year olds in primary care using intermittent ECG appears to be cost-effective at 3-year follow-up with high anticoagulants adherence and no increased mortality.

Survival in Out-of-Hospital Cardiac Arrest After Standard Cardiopulmonary Resuscitation or Chest Compressions Only Before Arrival of Emergency Medical Services: Nationwide Study During Three Guideline Periods.

BACKGROUND: In out-of-hospital cardiac arrest, chest compression-only cardiopulmonary resuscitation (CO-CPR) has emerged as an alternative to standard CPR (S-CPR), using both chest compressions and rescue breaths. Since 2010, CPR guidelines recommend CO-CPR for both untrained bystanders and trained bystanders unwilling to perform rescue breaths. The aim of this study was to describe changes in the rate and type of CPR performed before the arrival of emergency medical services (EMS) during 3 consecutive guideline periods in correlation to 30-day survival. METHODS: All bystander-witnessed out-of-hospital cardiac arrests reported to the Swedish register for cardiopulmonary resuscitation in 2000 to 2017 were included. Nonwitnessed, EMS-witnessed, and rescue breath-only CPR cases were excluded. Patients were categorized as receivers of no CPR (NO-CPR), S-CPR, or CO-CPR before EMS arrival. Guideline periods 2000 to 2005, 2006 to 2010, and 2011 to 2017 were used for comparisons over time. The primary outcome was 30-day survival. RESULTS: A total of 30 445 patients were included. The proportions of patients receiving CPR before EMS arrival changed from 40.8% in the first time period to 58.8% in the second period, and to 68.2% in the last period. S-CPR changed from 35.4% to 44.8% to 38.1%, and CO-CPR changed from 5.4% to 14.0% to 30.1%, respectively. Thirty-day survival changed from 3.9% to 6.0% to 7.1% in the NO-CPR group, from 9.4% to 12.5% to 16.2% in the S-CPR group, and from 8.0% to 11.5% to 14.3% in the CO-CPR group. For all time periods combined, the adjusted odds ratio for 30-day survival was 2.6 (95% CI, 2.4-2.9) for S-CPR and 2.0 (95% CI, 1.8-2.3) for CO-CPR, in comparison with NO-CPR. S-CPR was superior to CO-CPR (adjusted odds ratio, 1.2; 95% CI, 1.1-1.4). CONCLUSIONS: In this nationwide study of out-of-hospital cardiac arrest during 3 periods of different CPR guidelines, there was an almost a 2-fold higher rate of CPR before EMS arrival and a concomitant 6-fold higher rate of CO-CPR over time. Any type of CPR was associated with doubled survival rates in comparison with NO-CPR. These findings support continuous endorsement of CO-CPR as an option in future CPR guidelines because it is associated with higher CPR rates and overall survival in out-of-hospital cardiac arrest.

Searching for Atrial Fibrillation Poststroke: A White Paper of the AF-SCREEN International Collaboration.

Cardiac thromboembolism attributed to atrial fibrillation (AF) is responsible for up to one-third of ischemic strokes. Stroke may be the first manifestation of previously undetected AF. Given the efficacy of oral anticoagulants in preventing AF-related ischemic strokes, strategies of searching for AF after a stroke using ECG monitoring followed by oral anticoagulation (OAC) treatment have been proposed to prevent recurrent cardioembolic strokes. This white paper by experts from the AF-SCREEN International Collaboration summarizes existing evidence and knowledge gaps on searching for AF after a stroke by using ECG monitoring. New AF can be detected by routine plus intensive ECG monitoring in approximately one-quarter of patients with ischemic stroke. It may be causal, a bystander, or neurogenically induced by the stroke. AF after a stroke is a risk factor for thromboembolism and a strong marker for atrial myopathy. After acute ischemic stroke, patients should undergo 72 hours of electrocardiographic monitoring to detect AF. The diagnosis requires an ECG of sufficient quality for confirmation by a health professional with ECG rhythm expertise. AF detection rate is a function of monitoring duration and quality of analysis, AF episode definition, interval from stroke to monitoring commencement, and patient characteristics including old age, certain ECG alterations, and stroke type. Markers of atrial myopathy (eg, imaging, atrial ectopy, natriuretic peptides) may increase AF yield from monitoring and could be used to guide patient selection for more intensive/prolonged poststroke ECG monitoring. Atrial myopathy without detected AF is not currently sufficient to initiate OAC. The concept of embolic stroke of unknown source is not proven to identify patients who have had a stroke benefitting from empiric OAC treatment. However, some embolic stroke of unknown source subgroups (eg, advanced age, atrial enlargement) might benefit more from non-vitamin K-dependent OAC therapy than aspirin. Fulfilling embolic stroke of unknown source criteria is an indication neither for empiric non-vitamin K-dependent OAC treatment nor for withholding prolonged ECG monitoring for AF. Clinically diagnosed AF after a stroke or a transient ischemic attack is associated with significantly increased risk of recurrent stroke or systemic embolism, in particular, with additional stroke risk factors, and requires OAC rather than antiplatelet therapy. The minimum subclinical AF duration required on ECG monitoring poststroke/transient ischemic attack to recommend OAC therapy is debated.

Validity of daily self-pulse palpation for atrial fibrillation screening in patients 65 years and older: A cross-sectional study.

BACKGROUND: The European Society of Cardiology guidelines recommend (Class IA) single-time-point screening for atrial fibrillation (AF) using pulse palpation. The role of pulse palpation for AF detection has not been validated against electrocardiogram (ECG) recordings. We aimed to study the validity of AF screening using self-pulse palpation compared with an ECG recording conducted at the same time using a handheld ECG 3 times a day for 2 weeks. METHODS AND FINDINGS: In this cross-sectional screening study, patients 65 years of age and older attending 4 primary care centers (PCCs) outside Stockholm County were invited to take part in AF screening from July 2017 to December 2018. Patients were included irrespective of their reason for visiting the PCC. Handheld intermittent ECGs 3 times per day were offered to patients without AF for a period of 2 weeks, and patients were instructed in how to take their own pulse at the same time. A total of 1,010 patients (mean age 73 years, 61% female, with an average CHA2DS2-VASc score 2.9) participated in the study, and 27 (2.7%, 95% CI 1.8%-3.9%) new cases of AF were detected. Anticoagulants (ACs) could be initiated in 26 (96%, 95% CI 81%-100%) of these cases. A total of 53,782 simultaneous ECG recordings and pulse measurements were registered. AF was verified in 311 ECG recordings, of which the pulse was palpated as irregular in 77 recordings (25%, 95% CI 20%-30% sensitivity per measurement occasion). Of the 27 AF cases, 15 cases felt an irregular pulse on at least one occasion (56%, 95% CI 35%-75% sensitivity per individual). 187 individuals without AF felt an irregular pulse on at least one occasion. The specificity per measurement occasion and per individual was (98%, 95% CI 98%-98%) and (81%, 95% CI 78%-83%), respectively. CONCLUSIONS: AF screening using self-pulse palpation 3 times daily for 2 weeks has lower sensitivity compared with simultaneous intermittent ECG. Thus, it may be better to screen for AF using intermittent ECG without stepwise screening using pulse palpation. A limitation of this model could be the reduced availability of handheld ECG recorders in primary care centers.

Stepwise mass screening for atrial fibrillation using N-terminal B-type natriuretic peptide: the STROKESTOP II study.

AIMS: To study the prevalence of unknown atrial fibrillation (AF) in a high-risk, 75/76-year-old, population using N-terminal B-type natriuretic peptide (NT-proBNP) and handheld electrocardiogram (ECG) recordings in a stepwise screening procedure. METHODS AND RESULTS: The STROKESTOP II study is a population-based cohort study in which all 75/76-year-old in the Stockholm region (n = 28 712) were randomized 1:1 to be invited to an AF screening programme or to serve as the control group. Participants without known AF had NT-proBNP analysed and were stratified into low-risk (NT-proBNP <125 ng/L) and high-risk (NT-proBNP ≥125 ng/L) groups. The high-risk group was offered extended ECG-screening, whereas the low-risk group performed only one single-lead ECG recording. In total, 6868 individuals accepted the screening invitation of which 6315 (91.9%) did not have previously known AF. New AF was detected in 2.6% [95% confidence interval (CI) 2.2-3.0] of all participants without previous AF. In the high-risk group (n = 3766/6315, 59.6%), AF was diagnosed in 4.4% (95% CI 3.7-5.1) of the participants. Out of these, 18% had AF on their index-ECG. In the low-risk group, one participant was diagnosed with AF on index-ECG. The screening procedure resulted in an increase in known prevalence from 8.1% to 10.5% among participants. Oral anticoagulant treatment was initiated in 94.5% of the participants with newly diagnosed AF. CONCLUSION: N-terminal B-type natriuretic peptide-stratified systematic screening for AF identified 4.4% of the high-risk participants with new AF. Oral anticoagulant treatment initiation was well accepted in the group diagnosed with new AF.

Less dementia and stroke in low-risk patients with atrial fibrillation taking oral anticoagulation.

AIMS: To investigate if patients with atrial fibrillation (AF) without clear indication for oral anticoagulant (OAC) due to perceived low stroke risk may benefit from OAC treatment when also dementia and intracerebral bleeding risks are considered. METHODS AND RESULTS: Retrospective study of cross-matched national registries of all individuals in Sweden with a hospital diagnosis of AF between 2006 and 2014 (n = 456 960). Exclusion was made of patients with a baseline CHA2DS2-VASc score >1, not counting female sex, and of patients with previous diagnosis of dementia or intracranial bleeding. After exclusions, 91 254 patients remained in the study of whom 43% used OAC at baseline. Propensity score matching and falsification endpoints were used. Treatment with OAC was associated with lower risk of dementia after adjustment for death as a competing risk [subhazard ratio (sHR) 0.62 with 95% confidence interval (CI) 0.48-0.81]. Regarding the composite brain protection endpoint, OAC treatment was associated with an overall 12% lower risk (sHR 0.88, CI 0.72-1.00). This apparent benefit was restricted to patients aged >65 years, whereas OAC treatment of patients <60 years of age without risk factors appeared to do more harm than good. CONCLUSION: Low-risk AF patients who take OAC have lower risk of dementia than those who do not use OAC. Patients age >65 years appear to benefit from OAC treatment irrespective of stroke risk score.

Less dementia with oral anticoagulation in atrial fibrillation.

Aims: The association between atrial fibrillation (AF) and dementia is well documented, but it is not clear if oral anticoagulant treatment offers protection. The aim of the study is therefore to compare the incidence of new dementia in patients with AF with and without oral anticoagulants, and to explore if there is a difference between novel anticoagulants and warfarin in this respect. Methods and results: Retrospective registry study of all patients with hospital diagnosis of AF and no previous diagnosis of dementia in Sweden between 2006 and 2014. Propensity score matching, falsification endpoints, and analyses according to intention to treat as well as on-treatment principles were used. The study included 444 106 patients and over 1.5 million years at risk. Patients on anticoagulant treatment at baseline was associated with 29% lower risk of dementia than patients without anticoagulant treatment [hazard ratio (HR) 0.71, 95% confidence intervals (95% CI) 0.68-0.74] and 48% lower risk analysed on treatment (HR 0.52, 95% CI 0.50-055). Direct comparison between new oral anticoagulants and warfarin showed no difference (HR 0.97, 95% CI 0.67-1.40). Conclusion: The risk of dementia is higher without oral anticoagulant treatment in patients with AF. This suggests that early initiation of anticoagulant treatment in patients with AF could be of value in order to preserve cognitive function.

Screening for Atrial Fibrillation: A Report of the AF-SCREEN International Collaboration.

Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country- and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.

Early cardiopulmonary resuscitation in out-of-hospital cardiac arrest.

BACKGROUND: Three million people in Sweden are trained in cardiopulmonary resuscitation (CPR). Whether this training increases the frequency of bystander CPR or the survival rate among persons who have out-of-hospital cardiac arrests has been questioned. METHODS: We analyzed a total of 30,381 out-of-hospital cardiac arrests witnessed in Sweden from January 1, 1990, through December 31, 2011, to determine whether CPR was performed before the arrival of emergency medical services (EMS) and whether early CPR was correlated with survival. RESULTS: CPR was performed before the arrival of EMS in 15,512 cases (51.1%) and was not performed before the arrival of EMS in 14,869 cases (48.9%). The 30-day survival rate was 10.5% when CPR was performed before EMS arrival versus 4.0% when CPR was not performed before EMS arrival (P<0.001). When adjustment was made for a propensity score (which included the variables of age, sex, location of cardiac arrest, cause of cardiac arrest, initial cardiac rhythm, EMS response time, time from collapse to call for EMS, and year of event), CPR before the arrival of EMS was associated with an increased 30-day survival rate (odds ratio, 2.15; 95% confidence interval, 1.88 to 2.45). When the time to defibrillation in patients who were found to be in ventricular fibrillation was included in the propensity score, the results were similar. The positive correlation between early CPR and survival rate remained stable over the course of the study period. An association was also observed between the time from collapse to the start of CPR and the 30-day survival rate. CONCLUSIONS: CPR performed before EMS arrival was associated with a 30-day survival rate after an out-of-hospital cardiac arrest that was more than twice as high as that associated with no CPR before EMS arrival. (Funded by the Laerdal Foundation for Acute Medicine and others.).

Mobile-phone dispatch of laypersons for CPR in out-of-hospital cardiac arrest.

BACKGROUND: Cardiopulmonary resuscitation (CPR) performed by bystanders is associated with increased survival rates among persons with out-of-hospital cardiac arrest. We investigated whether rates of bystander-initiated CPR could be increased with the use of a mobile-phone positioning system that could instantly locate mobile-phone users and dispatch lay volunteers who were trained in CPR to a patient nearby with out-of-hospital cardiac arrest. METHODS: We conducted a blinded, randomized, controlled trial in Stockholm from April 2012 through December 2013. A mobile-phone positioning system that was activated when ambulance, fire, and police services were dispatched was used to locate trained volunteers who were within 500 m of patients with out-of-hospital cardiac arrest; volunteers were then dispatched to the patients (the intervention group) or not dispatched to them (the control group). The primary outcome was bystander-initiated CPR before the arrival of ambulance, fire, and police services. RESULTS: A total of 5989 lay volunteers who were trained in CPR were recruited initially, and overall 9828 were recruited during the study. The mobile-phone positioning system was activated in 667 out-of-hospital cardiac arrests: 46% (306 patients) in the intervention group and 54% (361 patients) in the control group. The rate of bystander-initiated CPR was 62% (188 of 305 patients) in the intervention group and 48% (172 of 360 patients) in the control group (absolute difference for intervention vs. control, 14 percentage points; 95% confidence interval, 6 to 21; P<0.001). CONCLUSIONS: A mobile-phone positioning system to dispatch lay volunteers who were trained in CPR was associated with significantly increased rates of bystander-initiated CPR among persons with out-of-hospital cardiac arrest. (Funded by the Swedish Heart-Lung Foundation and Stockholm County; ClinicalTrials.gov number, NCT01789554.).

A prospective 5-year follow-up after population-based systematic screening for atrial fibrillation.

Aims: Thrombo-embolic stroke risk in atrial fibrillation (AF) is significantly reduced with oral anticoagulant (OAC) treatment. Atrial fibrillation is often asymptomatic (silent) and therefore undiagnosed. The long-term course of silent AF as well as OAC treatment adherence after AF screening is not known. We aim at studying long-term adherence to OAC treatment, AF symptoms, and stroke incidence on population level after systematic AF screening. Methods and results: All inhabitants in a Swedish municipality who were born in 1934 and 1935 (n = 1335) were invited to participate in an AF screening trial between 2010 and 2012. Participants with a previously known or screening-detected AF were invited to a 5-year follow-up. Time trends of ischaemic stroke incidence were compared for population groups residing in the intervention municipality and in a surrounding control area where no AF screening trial was carried out. After the screening procedure, 103 of 121 participants (85%) with AF were treated with OAC. At the follow-up examination, 94 of 106 living patients (88%) were still on OAC treatment. Among the 23 long-term surviving patients who were diagnosed with paroxysmal AF during screening, 6 had developed permanent silent AF. The incidence of ischaemic stroke between ages 76-80 years declined significantly after the AF screening trial in the intervention area (P = 0.003) but not in the control area. Conclusion: Adherence to OAC treatment 5 years after AF screening was high. Silent AF has a natural course similar to symptomatic AF. The observed incidences of ischaemic stroke suggest a beneficial population-level effect of systematic AF screening.

ST segment depression on 24-hour electrocardiography predicts incident atrial fibrillation in two population-based cohorts.

Aims: ST-depression at 24hECG has not been studied in relation to atrial fibrillation (AF) risk. We aimed to determine whether ST-depression at 24hECG was associated with incident AF in two Swedish population-based cohorts - a sub-cohort of the Malmö Diet and Cancer study (MDCS), and the cohort 'Men born in 1914', and to determine whether 24hECG could be used to predict AF development. Methods and results: There were 378 acceptable 24hECG recordings in the MDCS (mean age 64.5 years, 43% men) and 394 acceptable recordings in 'Men born in 1914' (mean age 68.8 years). Incidence of AF was monitored using national registers of hospitalizations and outpatient visits in Sweden. Mean follow-up ± SD (cumulative incidence) was 10.4 ± 2 years (11.3%) in MDCS, and 10.9 ± 4 years (7.3%) in 'Men born in 1914'. ST-depressions were independently associated with incident AF; hazard ratio (HR) (95% CI) 2.41 (1.29-4.50, P = 0.006) and 2.28 (1.05-4.95, P = 0.038) after adjustment [age, sex, height, weight, systolic blood pressure, smoking, anti-hypertensive drugs, LDL/total cholesterol, and HOMA-IR (in MDCS)]. AF incidence was substantially lower in individuals who had neither ST-depressions or high supraventricular activity (SVA, negative predictive value 0.97 and 0.94, in MDCS and 'Men born in 1914', respectively), and similar in men and women. Conclusion: ST-depression at 24h-ECG is independently associated with incident AF, and incidence is substantially lower in individuals with neither ST-depression or high SVA. 24hECG can be used not only to diagnose AF but also to identify individuals at high and low AF risk.

High beat-to-beat blood pressure variability in atrial fibrillation compared to sinus rhythm.

PURPOSE: Atrial fibrillation (AF) is associated with an increased risk for cardiovascular morbidity and mortality, not entirely explained by thromboembolism. The underlying mechanisms for this association are largely unknown. Similarly, high blood pressure (BP) increases the risk for cardiovascular events. Despite this the interplay between AF and BP is insufficiently studied. The purpose of this study was to examine and quantify the beat-to-beat blood pressure variability in patients with AF in comparison to a control group of patients with sinus rhythm. MATERIALS AND METHODS: We studied 33 patients - 21 in atrial fibrillation and 12 in sinus rhythm - undergoing routine coronary angiography. Invasive blood pressure was recorded at three locations: radial artery, brachial artery and ascending aorta. Blood pressure variability, defined as average beat-to-beat blood pressure difference, was calculated for systolic and diastolic blood pressure at each site. RESULTS: We observed a significant difference (p < .001) in systolic and diastolic blood pressure variability between the atrial fibrillation and sinus rhythm groups at all locations. Systolic blood pressure variability roughly doubled in the atrial fibrillation group compared to the sinus rhythm group (4.9 and 2.4 mmHg respectively). Diastolic beat-to-beat blood pressure variability was approximately 6 times as high in the atrial fibrillation group compared to the sinus rhythm group (7.5 and 1.2 mmHg respectively). No significant difference in blood pressure variability was seen between measurement locations. CONCLUSIONS: Beat-to-beat blood pressure variability in patients with atrial fibrillation was substantially higher than in patients with sinus rhythm. Hemodynamic effects of this beat-to-beat variation in blood pressure may negatively affect vascular structure and function, which may contribute to the increased cardiovascular morbidity and mortality seen in patients with atrial fibrillation.