Detection of atrial fibrillation after ischemic stroke is challenging due to its paroxysmal nature. We aimed to assess predictors of paroxysmal atrial fibrillation using non-invasive surface ECG and transthoracic echocardiography to select candidates for atrial fibrillation screening. Ischemic stroke patients without documented atrial fibrillation (n = 110, 67 ± 10 years, 40 female) and a control group of age- and gender-matched patients with history of paroxysmal atrial fibrillation prior to stroke (n = 55, 67 ± 10 years, 19 female) comprised the study sample. Using non-invasive ECG monitoring for three weeks, short episodes of paroxysmal atrial fibrillation were detected in 24 of 110 patients (22 %). The standard 12-lead ECG with sinus rhythm at stroke onset was digitally processed and analyzed. Transthoracic echocardiography data were reviewed for these patients. Atrial fibrillation history was independently associated with P terminal force in lead V 1 > 40 mm*ms (OR 4.04 95 % CI 1.34–12.14, p = 0.013) and left atrial volume index (OR 1.08 95 % CI 1.03–1.13, p = 0.002; for LAVI > 40 mL/m2 OR 6.40 95 % CL 1.47–27.91, p = 0.013). Among patients without atrial fibrillation history, no ECG characteristics were predictive of atrial fibrillation detected after stroke. Left atrial volume index remained an independent predictor of atrial fibrillation detected after stroke (OR 1.09 95 % CI 1.02–1.16, p = 0.017). A cutoff of <40 mL/m2 had an 84 % negative predictive value for ruling out atrial fibrillation on ambulatory monitoring with a sensitivity of 50 % and a specificity of 86 %. In a post hoc analysis, left atrial dilatation assessed by left atrial volume index independently predicted atrial fibrillation after stroke in patients without prior atrial fibrillation history, while the other clinical or ECG markers were not predictive of atrial fibrillation detected early after ischemic stroke. This study is a post hoc analysis from the prospective case-control study registered in December 2011, ClinicalTrials.gov ID: NCT01325545 .

Aims Data from national discharge registers are commonly used to estimate prevalence and incidence of atrial fibrillation (AF) in epidemiology studies. However, sensitivity and specificity of register-based AF diagnosis have not been evaluated. We sought to assess the validity of AF diagnosis in the Swedish Patient Register against electrocardiography (ECG) documentation of AF. Methods and results The study sample comprised of 336 patients [median age 76 (interquartile range (IQR) 67–82 years, 136 female] with first-ever ischaemic stroke, enroled in the Lund Stroke Register from March 2001 to February 2002 and 1 : 1 age- and gender-matched control subjects without stroke from the population register. Data was exported from the patient register in October 2011 (the end of follow-up). Atrial fibrillation documentation by ECG was assessed using an electronic archive containing all ECGs taken in the hospital catchment area starting in 1988. A total of 7247 ECGs were reviewed, with the median number of ECGs per person being 7.5 (IQR 3–15). Atrial fibrillation was detected by ECG in 190 patients; and in 188 patients by linkage with patient register. In most patients, AF was documented first by ECG data, with median time to register diagnosis being 16 days (IQR 3–859). Specificity of AF diagnosis in the Swedish Patient Register was 93%, sensitivity was 80%. Conclusion Despite the high specificity, AF diagnosis in the Swedish Patient Register assessed in the population of ischaemic stroke patients and age- and gender-matched control subjects has modest sensitivity, which may result in underestimating prevalent and incident AF cases if only register data are used for identification of subjects with AF in epidemiology studies.

Interatrial block (IAB) is an ECG indicator of atrial fibrosis related to atrial remodeling and thrombus formation thus leading to embolic stroke and increasing mortality. We aimed to assess weather IAB predicted all-cause mortality during 10 years after ischemic stroke. The study sample comprised 235 patients (median age 74 (interquartile range 25–75% 65–81) years, 95 female) included in the Lund Stroke Register in 2001–2002, who had sinus rhythm ECGs at stroke admission. IAB was defined as a P-wave duration ≥120 ms without = partial IAB (n = 56) or with = advanced IAB (n = 41) biphasic morphology (±) in the inferior ECG leads. All-cause mortality was assessed via linkage with the Swedish Causes of Death Register. During follow-up 126 patients died (54%). Advanced IAB, but not partial, was associated with all-cause mortality in univariate Cox regression analysis (hazard ratio (HR) 1.98, 95% CI 1.27–3.09, p = 0.003). After adjustment for age, gender, severity of stroke measured by NIHSS scale and smoking status in patients without additional comorbidities advanced IAB independently predicted all-cause mortality (HR 7.89, 95% CI 2.01–30.98, p = 0.003), while in patients with comorbidities it did not (HR 1.01 95% CI 0.59–1.72, p = 0.966). Advanced IAB predicted all-cause mortality after ischemic stroke, but mostly in patients without additional cardiovascular comorbidities.