Geographic and socio-demographic differences in uptake of population-based screening for atrial fibrillation: The STROKESTOP I study.

BACKGROUND: The rationale behind screening for atrial fibrillation (AF) is to prevent ischemic stroke. Socio-demographic differences are expected to affect screening uptake. Geographic differences may provide further insights leading to targeted interventions for improved uptake. The objective of this study was to evaluate geographic and socio-demographic differences in uptake of AF screening in the population-based study STROKESTOP I. METHODS: STROKESTOP was carried out in two Swedish counties with a total population of 2.3 million inhabitants. Half of the residents aged 75-76years were randomized to the screening arm: invitation to clinical examination followed by ambulant ECG recording. Information on each invited person's residential parish (n=157) was used. On parish-level, aggregated data for the participants and non-participants, respectively, were obtained with respect to socioeconomic variables: educational level, disposable income, immigrant and marital status. Geo-maps displaying participation ratios were estimated by hierarchical Bayes methods. RESULTS: The overall participation rate was similar in men and women but lower in Stockholm, 47.6% (5665/11,903) than in Halland, 61.2% (1495/2443). Participation was clearly associated with the socioeconomic variables. Participation not taking into account socioeconomy varied more markedly across the parishes in the Stockholm county (range: 0.65-1.26) than in the Halland county (0.94-1.27). After adjustment for socioeconomic variables, a geographic variation remained in Stockholm, but not in Halland. CONCLUSION: Participation in AF screening varied according to socioeconomic conditions. Geographic variation in participation was marked in the Stockholm county, with only one screening clinic. Geo-mapping of participation yielded useful information needed to intervene for improved screening uptake.

Echocardiographic measures of atrial function may predict atrial fibrillation in stroke patients.

OBJECTIVE: In patients with a prior stroke or transient ischemic attack (TIA) and atrial fibrillation anticoagulant treatment is indicated. This study's purpose was to investigate if echocardiography can predict unknown AF in patients after stroke. DESIGN: Prospectively, 174 stroke/TIA patients without diagnosed AF underwent echocardiographic evaluation including tissue Doppler imaging (TDI) focusing on functional parameters of the left atrium and left ventricular diastolic function. AF screening was performed during 30 d. RESULTS: Fifteen patients (8.6%) were diagnosed with AF. Echocardiography in the AF group compared to those without AF, showed larger left atrial volume index (LAVI), (37.2 ± 6.7 vs. 31.6 ± 8.6 ml/m(2), p = 0.018), lower A' velocities in ventricular (5.9 ± 2.2 vs. 7.2 ± 1.6, p = 0.010) and atrial (4.8 ± 1.4 vs. 5.9 ± 1.4, p = 0.013) septa, higher LAVI/A' in ventricular septum (6.7 (5.0-8.7) vs. 4.2 (3.2-5.5), p = 0.001) and atrial septum (8.5 (5.9-11.0) vs. 5.1 (4.1-6.8), p = 0.003). Receiver operating characteristic analyses to detect AF was performed, area under the curve for LAVI was 0.71 (0.61-0.83), p = 0.008, and for LAVI/A' in ventricular septum 0.76 (0.59-0.93), p = 0.006 and atrial septum 0.78 (0.63-0.93), p = 0.002, respectively. CONCLUSIONS: LAVI and measures of atrial contraction as measured by TDI predict unknown AF in patients after an stroke/TIA and may be used to detect silent AF.

Cost-effectiveness of mass screening for untreated atrial fibrillation using intermittent ECG recording.

AIMS: The aim of this study was to estimate the cost-effectiveness of 2 weeks of intermittent screening for asymptomatic atrial fibrillation (AF) in 75/76-year-old individuals. METHODS AND RESULTS: The cost-effectiveness analysis of screening in 75-year-old individuals was based on a lifelong decision analytic Markov model. In this model, 1000 hypothetical individuals, who matched the population of the STROKESTOP study, were simulated. The population was analysed for different parameters such as prevalence, AF status, treatment with oral anticoagulation, stroke risk, utility, and costs. In the base-case scenario, screening of 1000 individuals resulted in 263 fewer patient-years with undetected AF. This implies eight fewer strokes, 11 more life-years, and 12 more quality-adjusted life years (QALYs) per 1000 screened individuals. The screening implies an incremental cost of €50 012, resulting in a cost of €4313 per gained QALY and €6583 per avoided stroke. CONCLUSIONS: With the use of a decision analytic simulation model, it has been shown that screening for asymptomatic AF in 75/76-year-old individuals is cost-effective.

Evolution of left ventricular ejection fraction after acute myocardial infarction: implications for implantable cardioverter-defibrillator eligibility.

BACKGROUND: Implantable cardioverter-defibrillator therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI). Although the risk of sudden cardiac death is highest in the first month after AMI, there is no survival benefit of early implantable cardioverter-defibrillator implantation, and the optimal time frame has yet to be established. Thus, the aim of this study was to investigate what proportion of post-AMI patients had improved LV function to such an extent that the indication for implantable cardioverter-defibrillator was no longer present. METHODS AND RESULTS: Patients admitted for AMI with reduced LVEF (≤40%) were eligible for inclusion. Repeat echocardiographic examinations were performed 5 days, 1 month, and 3 months after the AMI. We prospectively included 100 patients with LVEF of 31±5.8% after AMI. At the 1-month follow-up, 55% had an LVEF >35%. The main improvement in LVEF had occurred by 1 month. The mean difference in LVEF over the next 2 months was small, 1.9 percentage units. During the first 9 weeks, 10% of the patients suffered from life-threatening arrhythmias. CONCLUSIONS: Most patients have improved LVEF after AMI, and in the majority, the improvement can be confirmed after 1 month, implying that further delay of implantable cardioverter-defibrillator implantation may not be warranted. Life-threatening arrhythmias occurred in 10% of the patients, illustrating the high risk for sudden cardiac death in this population.

Improved screening for silent atrial fibrillation after ischaemic stroke.

OBJECTIVES: To what extent silent paroxysmal atrial fibrillation (AF) is present in ischaemic stroke patients has not been established. We hypothesized that brief intermittent long-term electrocardiogram (ECG) recordings at regular time intervals are more effective than short-term continuous ECG monitoring in detecting silent AF episodes. METHODS AND RESULTS: Consecutive patients who had suffered an ischaemic stroke/transient ischaemic attack (TIA) and were without known AF underwent a 24 h continuous ECG recording and performed 10 s rhythm registrations using a hand-held ECG recorder twice daily for 30 days and when arrhythmia symptoms occured. Two hundred and forty-nine stroke patients were included. Mean National Institute of Health Stroke Scale (NIHSS) score was 0.9 (0-10). In total, 17 patients were diagnosed with AF. One hundred and eight AF episodes were diagnosed in 15 patients using intermittent recording, out of which 22% where unscheduled symptom triggered episodes. In three patients AF was diagnosed with both methods and in two patients AF was detected exclusively with 24 h Holter monitoring. A significant difference in favour of the hand-held ECG was shown between the two methods (P = 0.013). The total prevalence of AF was 6.8% and increased to 11.8% in patients ≥75 years. No AF was found in patients <65 years. CONCLUSIONS: Prolonged brief intermittent arrhythmia screening substantially improves the detection of silent paroxysmal AF in patients with a recent ischaemic stroke/TIA, and thus facilitates the detection of patients who should receive oral anticoagulant treatment.