The main purpose of this study is to investigate the safety and outcomes of different treatment strategies, including best medical therapy (OAC [oral anticoagulation], antiplatelet [APT]) and left atrial appendage closure [LAAC] in acute ischemic stroke (AIS) patients with atrial fibrillation (AF) based on multimodal assessment from combined brain and cardiologic work-up, and to optimize secondary prevention.

Ischemic stroke is the leading cause of disability and mortality globally. Atrial fibrillation（AF） is a well-established risk factor for ischemic stroke and responsible for up to one-third of all strokes. AF-related ischemic strokes are more frequently fatal or disabling than non-AF strokes. The overall prevalence of known or newly diagnosed AF in stroke patients is approximately 39.0%. Detecting underlying AF remains important for secondary prevention of recurrent stroke, with a different strategy from atherosclerotic cause of stroke. The increasingly common use of prolonged cardiac monitoring (PCM) after ischemic stroke has greatly increased the detection rates of previously undiagnosed AF in ischemic strokes, which was demonstrated by a series of trials. Additionally, AF burden, defined as percentage of the time in AF during cardiac monitoring, has been regarded as an important prognostic risk factor for thromboembolism.

Currently, the CHA2DS2-VASc score is the most widely used scoring system for assessing ischemic stroke risk in patients with AF and basis for initiation of anticoagulation. Anticoagulation is currently recommended for male with CHA2DS2-VASc score≥2 or female with CHA2DS2-VASc score≥3. Direct oral anticoagulants (DOACs) have been increasingly used in the past decade due to their similar to superior efficacy to vitamin K antagonists (VKAs), but a lower intracerebral bleeding risk in non-valvular atrial fibrillation (NVAF), defined as AF in the absence of moderate to severe mitral stenosis or a mechanical heart valve. For patients with AF who cannot tolerate long-term OACs due to various relative or absolute contraindications, left atrial appendage closure (LAAC) offers an alternative treatment strategy for these patients. Moreover, as one-third of patients with ischemic stroke and AF may have concomitant large artery atherosclerosis or small vessel disease, it is still unclear whether these patients should be left untreated or treated with antiplatelet (APT), DOACs, or with LAAC.

Traditional clinical practice mainly focuses on the presence of AF but rarely incorporates AF burden into a risk stratification scoring system. To our knowledge, no studies to date have investigated recurrent stroke risk stratification in AIS patients with AF based on AF burden assessed by PCM, not to mention guidance of treatment strategy selection. Further, other multimodal assessments, such as cerebral CT/MRI (e.g. infarct size and location), serum biomarkers (e.g. BNP, troponin, D-dimer levels) and cardiac structural markers (e.g. LA volume or volume index, LAA morphologies) have been reported as promising prognostic factors of stroke severity and recurrence. A comprehensive evaluation system is still lacking. In this prospective and multicenter registry study, we determine to test the safety and effectiveness of best medical therapy (OAC, APT) and LAAC using multimodal assessment from combined brain and cardiologic work-up, with the aim to optimize secondary prevention in this patient population.

Inclusion Criteria:

1. Age > 18 years old；
2. Acute ischemic stroke with onset ≤ 14 days；
3. Previously or during this hospitalization diagnosed with non-valvular atrial fibrillation;
4. Informed consent obtained from the patient or his/her legal representative；

Exclusion Criteria:

1. Pacemaker, implantable cardioverter defibrillator or implantable cardiac monitor;
2. Left atrial appendage has been removed or post occlusion device implantation;
3. Transient AF secondary to other reversible disorders；
4. Life expectancy less than 1 year;
5. Patients that cannot complete subsequent follow-up (e.g. no fixed residence, overseas patients, etc.);
6. Females who are pregnant or in lactation;
7. Participating in other clinical trials that could confound the evaluation of the study;
8. Other circumstances that the investigator considers inappropriate for participation or may pose a significant risk to patients.

Adult patients who had acute ischemic stroke symptoms within 7 days and previously or during this hospitalization diagnosed with non-valvular atrial fibrillation.