Atrial fibrillation in ischemic stroke: Prevalence, long-term outcomes and secondary prevention therapy

Atrial fibrillation (AF) is a very-well known risk factor for ischemic stroke. The general aim of the study was to assess prevalence of AF in patients with first-ever ischemic stroke and to evaluate the impact of AF on outcomes during 10-year follow-up after the stroke event.
The thesis consists of a retrospective register-based study and a post hoc analysis from the prospective case-control study. The main study population of patients with first-ever ischemic stroke was enrolled in the Lund Stroke Register during 2001-2002 and followed up for 10 years from date of enrollment. Patients treated with ischemic stroke at Mayo Clinic (Rochester, MN, USA) were prospectively included in the case-control study and underwent three-week ambulatory ECG monitoring for AF detection.
For AF detection prior to stroke and during follow-up in the register-based study the combined approach was used with screening through regional electronic ECG archive and via linkage with the Swedish National Patient Register, in which validity of the AF diagnosis was assessed against ECG documentation. Clinical, echocardiographic and electrocardiographic predictors of AF onset were evaluated using medical records and sinus rhythm ECG taken at stroke admission. Oral anticoagulant therapy (OAC) was analyzed through Lund University Hospital anticoagulation database. All-cause mortality was assessed using the Cause of Death Register.
Pre-stroke prevalence of AF appeared to be 32.4% and was associated with a high CHA2DS2-VASc score. In stroke patients, short runs of AF on prolonged ambulatory ECG monitoring were associated with increased left atrial volume index (Study III). A high CHA2DS2-VASc score predicted the development of AF during the 10 years following the first-ever ischemic stroke. Permanent AF was associated with the worst prognosis, while the best prognosis during the 10-year follow-up was observed for ischemic stroke patients with recurrent atrial fibrillation treated with OAC. In conclusion, ischemic stroke patients with a high CHA2DS2-VASc score may be the target group for continuous AF screening and initiation of OAC therapy upon AF detection.

Every minute in the world anyone gets a stroke. One of the leading cause of stroke is arrhythmia – atrial fibrillation (AF) which leads to thrombus formation in the heart (left atrium) and as a result to occlusion of a brain artery. However, the detection of AF in stroke patients is a challenge due to its paroxysmal and asymptomatic nature. Documentation of AF in stroke patients is crucial for medical treatment of those patients. It is proved that using of medications which prevent thrombus formation (secondary prevention therapy) significantly improves survival in patients with AF after stroke.
The aim of the study was to assess the prevalence of AF in patients with first-ever ischemic stroke and to evaluate the impact of AF on long-term prognosis 10 years after stroke event.
We included in the study patients with first-ever ischemic stroke enrolled in the Lund Stroke Register (LSR) during 2001-2002 and followed them up during 10 years. In addition, patients treated with ischemic stroke at Mayo clinic (Rochester, MN, USA) were included in the analysis, they underwent three-weeks ambulatory ECG monitoring for AF detection.
For AF detection prior to stroke and during follow-up the combined approach was used with screening through regional electronic electrocardiographic (ECG) archive and via linkage with the Swedish National Patient Register. Risk of thromboembolic events, clinical, echocardiographic and ECG characteristics associated with development of AF after stroke were evaluated using medical records and sinus rhythm ECG taken at stroke admission. Secondary prevention therapy was analyzed through Lund University Hospital anticoagulation database. Survival was assessed using Cause of Death Register.
Prevalence of AF prior to stroke appeared to be 32,4% and was associated with high risk of thromboembolic events. AF detected on prolonged ambulatory ECG monitoring was associated with left atrium enlargement. High risk of thromboembolic events predicted the development of AF during 10 years after first-ever ischemic stroke. Chronic AF was associated with the worst prognosis, while the best prognosis during 10-year follow-up was observed for ischemic stroke patients with recurrent atrial fibrillation received secondary prevention therapy.
In conclusion, ischemic stroke patients with high risk of thromboembolic events might be the target group for continuous AF screening and initiation of secondary prevention therapy upon AF detection.