A genome-wide association scan in populations from Sweden, North America and China has identified two single-letter sequence variants on chromosome 4q25 as risk factors for atrial fibrillation, the most common form of cardiac arrhythmia. Both are adjacent to the PITX2 gene, known to be involved in early heart development. This work identifies PITX2 as a target for diagnostic tests and possibly for therapeutic intervention. As the most common cardiac arrythmia, atrial fibrillation is of interest to physicians, and has recently been shown to have genetic components. Gudjbartsson et al. have conducted a genome-wide association scan in populations from around the globe, and find a strong link to a gene involved in early heart development. This gene, PITX2, could be a candidate for therapeutic intervention. Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans and is characterized by chaotic electrical activity of the atria1. It affects one in ten individuals over the age of 80 years, causes significant morbidity and is an independent predictor of mortality2. Recent studies have provided evidence of a genetic contribution to AF3,4,5. Mutations in potassium-channel genes have been associated with familial AF6,7,8,9,10 but account for only a small fraction of all cases of AF11,12. We have performed a genome-wide association scan, followed by replication studies in three populations of European descent and a Chinese population from Hong Kong and find a strong association between two sequence variants on chromosome 4q25 and AF. Here we show that about 35% of individuals of European descent have at least one of the variants and that the risk of AF increases by 1.72 and 1.39 per copy. The association with the stronger variant is replicated in the Chinese population, where it is carried by 75% of individuals and the risk of AF is increased by 1.42 per copy. A stronger association was observed in individuals with typical atrial flutter. Both variants are adjacent to PITX2, which is known to have a critical function in left–right asymmetry of the heart13,14,15.

Background and Purpose—: We aimed to establish the prevalence, characteristics, and outcomes of intracranial atherosclerosis (ICAS) in China by a large, prospective, multicenter study. Methods—: We evaluated 2864 consecutive patients who experienced an acute cerebral ischemia <7 days after symptom onset in 22 Chinese hospitals. All patients underwent magnetic resonance angiography, with measurement of diameter of the main intracranial arteries. ICAS was defined as ≥50% diameter reduction on magnetic resonance angiography. Results—: The prevalence of ICAS was 46.6% (1335 patients, including 261 patients with coexisting extracranial carotid stenosis). Patients with ICAS had more severe stroke at admission and stayed longer in hospitals compared with those without intracranial stenosis (median National Institutes of Health Stroke Scale score, 3 versus 5; median length of stay, 14 versus 16 days; both P <0.0001). After 12 months, recurrent stroke occurred in 3.27% of patients with no stenosis, in 3.82% for those with 50% to 69% stenosis, in 5.16% for those with 70% to 99% stenosis, and in 7.27% for those with total occlusion. Cox proportional hazards regression analyses showed that the degree of arterial stenosis, age, family history of stroke, history of cerebral ischemia or heart disease, complete circle of Willis, and National Institutes of Health Stroke Scale score at admission were independent predictors for recurrent stroke at 1 year. The highest rate of recurrence was observed in patients with occlusion with the presence of ≥3 additional risk factors. Conclusions—: ICAS is the most common vascular lesion in patients with cerebrovascular disease in China. Recurrent stroke rate in our study was lower compared with those of previous clinical trials but remains unacceptably high in a subgroup of patients with severe stenosis.

At the same time as the world recognizes the rapid economic development in China, Chinese healthcare system has also had significant improvement. However, this nation of 1.4 billion faces tough challenges in treating stroke, the leading cause of death in China. The recently completed Chinese National Stroke Registry has provided new information on the status of stroke epidemiology, diagnosis, management, and prevention strategies in China. In this article, we summarized these new findings, described the effort of providing and improving stroke care, and illustrated the challenges in risk factor modification and secondary stroke prevention. Well-designed epidemiological surveys and clinical trials for stroke prevention and management are still urgently needed in China.

Background and Purpose— Large artery intracranial occlusive disease (LAICOD) is a common and important stroke subtype. In this commentary, we review key epidemiological aspects of LAICOD. Summary of Review— LAICOD has emerged as the most common stroke subtype worldwide and is associated with a high risk of recurrent stroke. Hypotheses have been proposed to explain causation, which include such factors as traditional cardiovascular risk factors, high blood volume states, and genetic abnormalities. Approaches to treatment such as antithrombotic therapies, revascularization procedures, and counterpulsation devices hold promise. Conclusions— LAICOD poses a major stroke problem worldwide and is likely the most common stroke subtype. The etiology and treatment of this disorder remain poorly defined. International collaborations are needed to pool collective knowledge and develop definitive studies to better understand causation and treatment of LAICOD.

Previous studies conducted between 1997 and 2003 estimated that the risk of stroke or an acute coronary syndrome was 12 to 20% during the first 3 months after a transient ischemic attack (TIA) or minor stroke. The TIAregistry.org project was designed to describe the contemporary profile, etiologic factors, and outcomes in patients with a TIA or minor ischemic stroke who receive care in health systems that now offer urgent evaluation by stroke specialists. We recruited patients who had had a TIA or minor stroke within the previous 7 days. Sites were selected if they had systems dedicated to urgent evaluation of patients with TIA. We estimated the 1-year risk of stroke and of the composite outcome of stroke, an acute coronary syndrome, or death from cardiovascular causes. We also examined the association of the ABCD² score for the risk of stroke (range, 0 [lowest risk] to 7 [highest risk]), findings on brain imaging, and cause of TIA or minor stroke with the risk of recurrent stroke over a period of 1 year. From 2009 through 2011, we enrolled 4789 patients at 61 sites in 21 countries. A total of 78.4% of the patients were evaluated by stroke specialists within 24 hours after symptom onset. A total of 33.4% of the patients had an acute brain infarction, 23.2% had at least one extracranial or intracranial stenosis of 50% or more, and 10.4% had atrial fibrillation. The Kaplan–Meier estimate of the 1-year event rate of the composite cardiovascular outcome was 6.2% (95% confidence interval, 5.5 to 7.0). Kaplan–Meier estimates of the stroke rate at days 2, 7, 30, 90, and 365 were 1.5%, 2.1%, 2.8%, 3.7%, and 5.1%, respectively. In multivariable analyses, multiple infarctions on brain imaging, large-artery atherosclerosis, and an ABCD² score of 6 or 7 were each associated with more than a doubling of the risk of stroke. We observed a lower risk of cardiovascular events after TIA than previously reported. The ABCD² score, findings on brain imaging, and status with respect to large-artery atherosclerosis helped stratify the risk of recurrent stroke within 1 year after a TIA or minor stroke. (Funded by Sanofi and Bristol-Myers Squibb.)