Short-Term Ambient Air Pollution Exposure and Risk of Out-of-Hospital Cardiac Arrest in Sweden: A Nationwide Case-Crossover Study.

Background Air pollution is one of the main risk factors for cardiovascular disease globally, but its association with out-of-hospital cardiac arrest at low air pollution levels is unclear. This nationwide study in Sweden aims to investigate if air pollution is associated with a higher risk of out-of-hospital cardiac arrest in an area with relatively low air pollution levels. Methods and Results This study was a nationwide time-stratified case-crossover study investigating the association between short-term air pollution exposures and out-of-hospital cardiac arrest using data from the SRCR (Swedish Registry for Cardiopulmonary Resuscitation) between 2009 and 2019. Daily air pollution levels were estimated in 1×1-km grids for all of Sweden using a satellite-based machine learning model. The association between daily air pollutant levels and out-of-hospital cardiac arrest was quantified using conditional logistic regression adjusted for daily air temperature. Particulate matter <2.5 µm exposure was associated with a higher risk of out-of-hospital cardiac arrest among a total of 29 604 cases. In a multipollutant model, the association was most pronounced for intermediate daily lags, with an increased relative risk of 6.2% (95% CI, 1.0-11.8) per 10 µg/m3 increase of particulate matter <2.5 µm 4 days before the event. A similar pattern of association was observed for particulate matter <10 µm. No clear association was observed for O3 and NO2. Conclusions Short-term exposure to air pollution was associated with higher risk of out-of-hospital cardiac arrest. The findings add to the evidence of an adverse effect of particulate matter on out-of-hospital cardiac arrest, even at very low levels below current regulatory standards.

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.

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.

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.

Factors predicting participation and potential yield of screening-detected disease among non-participants in a Swedish population-based atrial fibrillation screening study.

BACKGROUND: The success of any screening program is dependent on participation. The characteristics of participants vs. non-participants have been studied and non-participants usually have a higher risk of disease. The potential yield of screening-detected disease in non-participants could be of interest to several screening programs. AIMS: This is a sub-study to STROKESTOP II, a Swedish atrial fibrillation screening study. The aim was to study factors predicting participation and to estimate the potential yield of screening-detected disease in non-participants. METHODS: Individual, anonymized data for participants and non-participants with respect to socioeconomic factors, medical history and drugs dispensed were obtained from Swedish registries. A random forest model was trained to predict propensity scores for participation. The propensity scores were used to estimate potential screening-detected disease among non-participants. RESULTS: Non-participants (n = 7086) had lower income, were more likely to have been hospitalized and had higher CHA2DS2-VASc scores compared to participants (n = 6868). The strongest factor predicting non-attendance was low income. The weighted estimates suggested that the yield of new atrial fibrillation was 2.4% in non-participants compared to 2.3% in the participants, which was not significant. CONCLUSIONS: Non-participants had higher CHA2DS2-VASc scores, indicating a higher stroke-risk and presumable benefit from attending screening, although estimated new atrial fibrillation detected was not significantly more common when compared to participants. Low income was the strongest factor for predicting non-attendance and should be a focus area when planning future screening scenarios.

Evaluation of patients with high burden of premature ventricular contractions by comprehensive transthoracic echocardiography.

Background: The prevalence and prognosis of premature ventricular contractions (PVCs) among individuals without structural heart disease are uncertain. Standard transthoracic echocardiography is a common method in evaluation of underlying cardiovascular disease and is recommended as a diagnostic method in PVC patients. However, it is unclear whether comprehensive echocardiographic examination can identify pathological findings in PVC patients with a normal standard echocardiogram. Method: We included forty consecutive patients with a high PVC burden (>10,000 PVCs/day) and normal findings at a standard echocardiogram and exercise test. All subjects were investigated by a comprehensive echocardiographic examination using parameters usually not included in a routine work-up. We compared the results with 22 age and sex-matched controls. Results: In six additional parameters-global longitudinal strain, right ventricular strain, septal-lateral delay, ventricular-arterial coupling, integrated backscatter and left atrial activation time-a statistically significant difference was shown between PVC patients and controls. Among these parameters, global longitudinal strain had a high reliability between operators. Conclusions: Despite normal findings at standard echocardiography, the PVC group showed signs of impaired heart function when more comprehensive echocardiography parameters were used.

Short-term ambient air pollution exposure and risk of atrial fibrillation in patients with intracardiac devices.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with substantial morbidity and mortality. Short-term exposure to fine particulate matter (PM2.5) has been causally linked to higher risk of cardiovascular disease, but the association with atrial fibrillation (AF) is less clear. Methods: We conducted a time-stratified case-crossover study to estimate the association between short-term air pollution levels and risk of AF episodes. The episodes were identified among patients with paroxysmal AF and an intracardiac devices able to register and store AF episodes. We obtained air pollution and temperature data from fixed monitoring stations and used conditional logistic regression to quantify the association of PM2.5, particulate matter (PM10), nitrogen dioxide (NO2) and ozone (O3) with onset of AF episodes, adjusting for temperature and public holidays.". Results: We analyzed 584 episodes of AF from 91 participants and observed increased risk of AF episodes with PM2.5 levels for the 48-72 hours lag (OR 1.05; CI [1.01,1.09] per IQR)] and 72-96 hours (OR 1.05 CI [1.00,1.10] per IQR). Our results were suggestive of an association between O3 levels and AF episodes during the warm season. We did not observe any statistically significant associations for PM10 nor NO2. Conclusion: Short-term increases in PM2.5 in a low-pollution level environment were associated with increased risk of AF episodes in a population with intracardiac devices. Our findings add to the evidence of a potential triggering of AF by short-term increases in air pollution levels, well below the new WHO air quality guidelines.

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.

Magnetic Resonance Detects Structural Heart Disease in Patients with Frequent Ventricular Ectopy and Normal Echocardiographic Findings.

The prognosis of patients with ventricular ectopy and a normal heart, as evaluated by echocardiography, is virtually unknown. Cardiac magnetic resonance (CMR) can detect focal ventricular anomalies that could act as a possible site of origin for premature ventricular contractions (PVCs). The aim of this study was to investigate the presence of cardiac anomalies in patients with normal findings at echocardiogram. METHODS: Fifty-one consecutive patients (23 women, 28 men, mean age 59 years) with very high PVC burden (>10,000 PVC/day) and normal findings at standard echocardiography and exercise test were examined with CMR. The outcome was pathologic findings, defined as impaired ejection fraction, regional wall motion abnormalities, abnormal ventricular volume, myocardial edema and fibrosis. RESULTS: Sixteen out of 51 patients (32%) had structural ventricular abnormalities at CMR. In five patients CMR showed impairment of the left ventricular and/or right ventricular systolic function, and six patients had a dilated left and/or right ventricle. Regional wall motion abnormalities were seen in six patients and fibrosis in four. No patient had CMR signs of edema or met CMR criteria for arrhythmogenic right ventricular cardiomyopathy. Five patients had extra-ventricular findings (enlarged atria in three cases, enlarged thoracic aorta in one case and pericardial effusion in one case). CONCLUSIONS: In this study 16 out of 51 patients with a high PVC burden and normal findings at echocardiography showed signs of pathology in the ventricles with CMR. These findings indicate that CMR should be considered in evaluating patients with a high PVC burden and a normal standard investigation.

Progression and clinical manifestations in screening-detected atrial fibrillation: A follow-up of the STROKESTOP study.

BACKGROUND: There is a lack of data on atrial fibrillation (AF) progression after AF screening. HYPOTHESIS: We studied the hypothesis that progression of AF subtype after AF screening was similar to the progression noted in clinical AF cases. We also studied predictors for AF progression and AF symptoms during 5-year follow-up. METHODS: All participants from the STROKESTOP study with screening-detected AF were included in this prospective cohort study (n = 218). Deceased patients, patients with dementia and/or patients receiving institutional care were excluded (n = 31). Patients were interviewed at their visit regarding symptoms, treatment with oral anticoagulation and clinical events during follow-up and instructed to record ECG using a handheld ECG recording twice daily for two weeks. RESULTS: A total of 187 patients were invited for follow-up and 120 (64%) participated. The mean age was 81.0 ± 0.6 years and 56 (47%) of the participants were women. The mean follow-up time was 5.3 ± 0.4 years. Among the participants with 5-year follow-up data available, 18% (22/120) were diagnosed with permanent AF at study entry, compared to 49/120 (41%) after five years (p < 0.001). Among patients with paroxysmal AF at study entry, 33/98 (34%) had progressed to permanent AF after five years. Among participants approximately half remained asymptomatic, whereas 48% reported predominantly mild symptoms. None of the components of CHA2DS2-VASc were significantly predictive of AF progression. CONCLUSIONS: The progression for screening-detected AF is like that of clinically detected AF. Half of the patients with screening-detected AF report symptoms over time, and symptoms were generally mild.

Performance of pulse palpation compared to one-lead ECG in atrial fibrillation screening.

BACKGROUND: The 2020 European Society of Cardiology atrial fibrillation guidelines recommend opportunistic screening for atrial fibrillation by pulse taking or ECG rhythm strip in those aged over 65 years. HYPOTHESIS: We aimed to compare the diagnostic accuracy of pulse palpation to ECG rhythm strip when screening for atrial fibrillation. A secondary aim was to investigate whether participants with palpitations were more likely to be diagnosed with new atrial fibrillation. METHODS: The study population were 75/76 year old individuals that participated in the STROKESTOP II study, a Swedish screening study for atrial fibrillation. Pulse palpation of the radial pulse for 30 sec was performed by healthcare professionals and recorded as regular or irregular. Thereafter a 30-sec single-lead ECG was registered. Patients were asked also if they had a history of palpitations. RESULTS: Of the 6159 participants included in the study, 461 (7.5%) had irregular pulse. Twenty-two (4.8%) of those with irregular pulse were diagnosed with atrial fibrillation on single-lead ECG rhythm strip. Among those with regular pulse, 6 (0.1%) cases of new atrial fibrillation were found. The sensitivity of the pulse palpation test was 78.6% and positive predictive value 4.8%. The proportion of newly diagnosed atrial fibrillation was not different between those with and without history of palpitations. CONCLUSION: Pulse palpation was inferior to single-lead ECG when screening for atrial fibrillation. We therefore advocate the use of single-lead ECG rather than pulse palpation when screening for atrial fibrillation. Palpitations did not predict atrial fibrillation.

Short-term associations between ambient air pollution and acute atrial fibrillation episodes.

INTRODUCTION: Atrial fibrillation (AF), prevalent in approximately 1-3% of the population, is associated with a higher risk of stroke, dementia, mortality, and a reduced quality of life. Air pollution may be associated with heart rhythm disturbances, but there is limited evidence regarding whether short-term changes in air pollution levels are associated with acute onset of AF episodes. METHODS: We screened 8,899 randomly selected 75-yearolds living in Stockholm without previously known AF for AF using home-based short-term ambulatory 1-lead ECG-measurements 2-4 times a day for 14 days. Screenings were carried out in 2012-2013 and 2016-2018. We used generalized estimating equations to quantify the association between PM2.5, PM10, NO2 and O3 obtained from a fixed monitoring station and risk of AF onset among participants with AF observed during the screening period, adjusting for temperature, relative humidity and temporal factors. We explored potential susceptible subgroups. RESULTS: Among 218 participants with 469 AF episodes we observed higher odds of AF following higher 24-hour mean levels of PM10 and O3, reaching statistical significance for PM10 levels averaged over the previous 12-24-hours [OR 1.10 (95%CI 1.01-1.19) per IQR of PM10 (7.8 µg/m3)]. In subgroup analyses, PM2.5 was more strongly associated with AF among participants with hypertension and PM10 and O3 were more strongly associated with AF among participants with diabetes and overweight. CONCLUSION: These results suggest that in an urban setting with relatively low levels of ambient air pollution, hourly changes in pollutant levels may increase the risk of acute episodes of both asymptomatic and symptomatic AF, especially among people with diabetes, hypertension or overweight.

Brief episodes of rapid irregular atrial activity (micro-AF) are a risk marker for atrial fibrillation: a prospective cohort study.

BACKGROUND: Short supraventricular tachycardias with atrial fibrillation (AF) characteristics are associated with an increased risk of developing AF over time. The aim of this study is to determine if presence of very short-lasting episodes of AF-like activity (micro-AF) can also be used as a marker of undiagnosed silent atrial fibrillation. METHODS: In the STROKESTOP II study, a Swedish mass screening study for AF among 75- and 76-year-olds, participants with NT-proBNP ≥125 ng/L performed intermittent ECG recordings 30 s, four times daily for 2 weeks. Participants with micro-AF (sudden onset of irregular tachycardia with episodes of ≥5 consecutive supraventricular beats and total absence of p-waves, lasting less than 30 s) were invited to undergo extended AF screening using continuous event recording for 2 weeks. A control group of individuals without micro-AF was examined using the same ECG modalities. RESULTS: Out of 3763 participants in STROKESTOP II who had elevated NT-proBNP levels and were free of AF, n = 221 (6%) had micro-AF. The majority of participants with micro-AF (n = 196) accepted further investigation with continuous ECG monitoring which showed presence of AF in 26 of them. In the control group (n = 250), continuous monitoring detected 7 new AF cases. Thus, AF was significantly more common in the micro AF group (13%) compared to the control group (3%), p < 0.001. CONCLUSIONS: Presence of short-lasting episodes of AF-like activity (micro-AF) indicates increased likelihood for undetected AF. Continuous screening therefore seems recommendable if a finding of AF would change clinical management. TRAIL REGISTRATION: ClinicalTrials.gov, identifier: NCT02743416, registered April 19, 2016.

Clinical and echocardiographic characteristics of individuals aged 75/76 years old with screening-detected elevated NT-proBNP levels.

Background: High plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) indicate increased probability of congestive heart failure (CHF) and atrial fibrillation (AF) and are associated with poor prognosis. Objective: We aimed to describe the clinical and echocardiographic characteristics of a population of individuals aged 75/76 years old with NT-proBNP ≥900 ng/L without previously known CHF or AF. Methods: All individuals aged 75/76 years in the Stockholm region were randomised to a screening study for AF. Half of them were invited to screening. Of those invited, 49.5% agreed to participate. Individuals with NT-proBNP ≥900 ng/L without known CHF were invited for further clinical evaluation. Results: Among 6315 participants without AF who had NT-proBNP sampled, 102 without previously known CHF had ≥900 ng/L. Of these, 93 completed further clinical investigations. In the population that was clinically investigated, 53% were female, and the median NT-proBNP was 1200 ng/L. New AF was found in 28 (30%). The NT-proBNP value in this group was not significantly different from those where AF was not detected (median 1285 vs 1178 ng/L). Patients with newly detected AF had larger left atrial volume and higher pulmonary artery pressure than those without AF. Preserved left ventricular ejection fraction (≥50%) was found in 86% of the participants, mid-range ejection fraction (40%-49%) in 3.2% and reduced ejection fraction (<40%) in 10.8%. Thirteen patients (14%) had other serious cardiac disorders that required medical attention. Conclusion: Elderly individuals with NT-proBNP levels ≥900 ng/L constitute a population at high cardiovascular risk even in the absence of diagnosed CHF or AF, and therefore merit further investigation.

Intermittent vs continuous electrocardiogram event recording for detection of atrial fibrillation-Compliance and ease of use in an ambulatory elderly population.

BACKGROUND: There are many atrial fibrillation (AF) screening devices available. Validation studies have mainly been performed in optimal settings in the young population. HYPOTHESIS: We aim to compare the yield of AF detection, compliance, and patient-based experience in an ambulatory elderly population by using intermittent electrocardiogram (ECG) recordings and continuous event recording simultaneously. METHODS: The study participants were part of the STROKESTOP II study, a Swedish screening study for AF. All participants were 75/76 years of age, were clinically free of AF, and had N-terminal pro b-type natriuretic peptides levels ≥125 ng/L. AF screening was performed in parallel during a 2-week period, using a continuous event recording device (R-test 4; Novacor) and 30-second intermittent recordings using a handheld ECG device (Zenicor II) four times daily. Participants were asked to fill out a questionnaire with regard to compliance and ease of use of the devices. RESULTS: During continuous event recording, 6% (n = 15/269) were diagnosed with AF and intermittent ECG detected AF in 2% (n = 5/269) of the participants (P = .002). No new cases of AF were detected using intermittent ECG monitoring only, but some episodes were detected in parallel for patients. On a graded ordinal scale of 1 to 5, with 1 reflecting "very easy to use", continuous monitoring was graded 2 (interquartile range [IQR]: 1-3) compared to intermittent 1 (IQR: 1-1) (P < .001). CONCLUSION: Continuous event recording detected three times more AF compared to intermittent ECG in an elderly ambulatory population. Compliance and user-friendliness were rated higher for the intermittent ECG device.

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.

Does stress echocardiography add incremental value to baseline ejection fraction for the early identification of candidates for implantable defibrillators?

Objective: A reduction in left ventricular ejection fraction (EF) remains the strongest indicator of increased risk of sudden cardiac death after an acute myocardial infarction (AMI). Guidelines recommend that patients with an EF ≤35%, 6-12 weeks after AMI should be considered for implantable cardioverter defibrillator (ICD) therapy. Stress echocardiography is a safe method to detect viability in a stunned myocardium. The purpose of this study was to investigate if stress echocardiography early after AMI could identify ICD candidates before discharge. Methods: Ninety-six patients with EF ≤40% early after AMI were prospectively included in a cohort study, and investigated by baseline and stress echocardiography before discharge. Follow-up echocardiography was performed after 3 months. EF, mitral annular plane systolic excursion (MAPSE) and peak systolic velocity (PSV) were determined for each examination. Results: There were 80 (83%) patients who completed the baseline, stress and follow-up echocardiography. Among them there were 32 (40%) patients who met the ICD criteria of EF ≤35% at 3 months. For these patients, EF, MAPSE and PSV were significantly lower than for those patients who recovered. The area under the receiver operating characteristic curve (AUC) was 85% (95% CI 0.74 to 0.94) for baseline EF to predict non-recovery. None of the other variables had a higher AUC. Conclusion: Patients who met the ICD criteria of EF ≤35% at 3 months after myocardial infarction had lower EF, MAPSE and PSV on baseline and stress echocardiograph before discharge. Stress echocardiography did not add additional value in predicting non-recovery.

Deactivation of implantable defibrillators at end of life - Can we do better?

INTRODUCTION: Dying patients with implantable defibrillators (ICD) have a risk of receiving unnecessary shocks before death. The aim of this study was to investigate if deactivation of shock therapy at end-of-life has increased since publication of new guidelines in 2010 on ICD management. METHOD AND RESULTS: This is a study of two groups of ICD patients who died in hospitals before and after publication of new guidelines. Group 1 consists of 89 patients who died between 2003 and 2010. Group 2 consists of 252 patients, the total number of ICD patients in Sweden who died in hospital during 2014. Data was obtained from the Swedish ICD and Pacemaker Registry, Swedish Tax Agency and patient medical notes. Two-thirds died in wards other than Cardiology. Fifty-four percent in group 1 had a Do-Not-Resuscitate-order (DNR) compared to 73% in group 2. Shock deactivation was present in 52% in group 1 and 67% in group 2. The difference in shock deactivation between group 1 and 2 was only significant (p = 0.014) for DNR-patients treated in Cardiology. A significant difference (p = 0.036) was found in deactivation within group 2 between DNR-patients in Cardiology vs. DNR-patients in Non-Cardiology wards. CONCLUSION: Two-thirds of ICD patients die in wards other than Cardiology. Since publication of guidelines on ICD management there is a general increase in shock deactivation for DNR-patients, but only significant for patients in Cardiology. This implicate that actions have to be taken for patients treated in Non-Cardiology wards to bridge the gap between guidelines recommendations and clinical practice.

Usefulness of Short-Lasting Episodes of Supraventricular Arrhythmia (Micro-Atrial Fibrillation) as a Risk Factor for Atrial Fibrillation.

According to the present European Society of Cardiology's guidelines for atrial fibrillation (AF), the definition of AF contains a 30-second time criterion, based on consensus. The aim of this cohort study is to evaluate whether very short-lasting episodes of AF, micro-AF, are risk factors for developing AF and to compare AF detection between continuous and intermittent ECG recordings applied in parallel. All participants, n = 102, were identified from the STROKESTOP study, a Swedish mass-screening study for AF. Participants were divided into 2 groups depending on results in the STROKESTOP study: a micro-AF group (with abrupt onset episodes of ≥4 consecutive supraventricular beats, irregular rate-to-rate intervals, absence of regular p waves, lasting for <30 seconds), n = 54, and a control group, n = 48. After a follow-up period participants who were clinically free of AF were invited to undergo repeat AF screening during a 2-week period, using continuous ECG recording and 30 seconds intermittent recordings simultaneously. After 2.3years of follow-up, significantly more participants in the micro-AF group had developed AF, 27 of 54 (50%), compared with the control group, 5 of 48 (10%), p < 0.001. Among the 94 participants not already diagnosed with AF who underwent AF-screening, 25 of 25 (100%) AF cases were detected with help of continuous monitoring whereas 10 of 25 (40%) AF cases were found with intermittent ECGs. In conclusion, micro-AF seems to be an important risk factor for the development of AF in an elderly population. The detection of AF was significantly higher using 2 weeks of continuous ECG monitoring compared with intermittent 30-second ECG recordings twice daily for 2 weeks.

Increased Cardiovascular Mortality and Morbidity in Patients Treated for Toxic Nodular Goiter Compared to Graves' Disease and Nontoxic Goiter.

BACKGROUND: Previous research has suggested an increased risk of death and cardiovascular disease in patients treated for hyperthyroidism. However, studies on this subject are heterogeneous, often based on old data, or have not considered the impact that treatment for hyperthyroidism might have on cardiovascular risk. It is also unclear whether long-term prognosis differs between Graves' disease and toxic nodular goiter. The aim of this study was to use a very large cohort built on recent data to assess whether improvements in cardiovascular care might have changed the prognosis over time. The study also investigated the impact of different etiologies of hyperthyroidism. METHODS: This was an observational register study for the period 1976-2012, with subjects followed for a median period of 18.4 years. Study patients were Stockholm residents treated for Graves' disease or toxic nodular goiter with either radioactive iodine or surgery (N = 12,239). This group was compared to Stockholm residents treated for nontoxic goiter (N = 3685), with adjustments made for age, sex, comorbidities, and time of treatment. Comparisons were also made to the general population of Stockholm. Outcomes were assessed in terms of all-cause and cardiovascular mortality as well as cardiovascular morbidity. RESULTS: The hazard ratios (HR) for all-cause mortality and for cardiovascular mortality were 1.27 [confidence interval (CI) 1.20-1.35] and 1.29 [CI 1.17-1.42], respectively, for hyperthyroid patients compared to those with nontoxic goiter. For cardiovascular morbidity, the HR was 1.12 [CI 1.06-1.18]. Patients aged ≥45 years who were treated for toxic nodular goiter were generally at greater risk than others, and those included from the year 1990 and onwards were at greater risk than those included earlier. Increased all-cause mortality, as well as cardiovascular mortality and morbidity, were also seen in comparisons with the general population. CONCLUSIONS: This is the first large study to indicate that the long-term risk of death and cardiovascular disease in hyperthyroid subjects is due to the hyperthyroidism itself and not an effect of confounding introduced by its treatment. Much of the excess risk is confined to individuals treated for toxic nodular goiter. Despite advances in cardiovascular care during recent decades, hyperthyroidism is still a diagnosis associated with increased cardiovascular morbidity and mortality.