Atrial fibrillation (AF) is associated with a high risk of thromboembolic events, and its prevalence is projected to increase because of population aging. 17 Indeed, the thromboembolic complications of AF are an important cause of morbidity and mortality. The CHADS 2 and CHA 2 DS 2 -VASc scores are useful for thromboembolic risk stratification. 18,19 Background-Coronary artery embolism (CE) is recognized as an important nonatherosclerotic cause of acute myocardial infarction. Its prevalence, clinical features, and prognosis remain insufficiently characterized. Methods and Results-We screened 1776 consecutive patients who presented with de novo acute myocardial infarction between 2001 and 2013. CE was diagnosed based on criteria encompassing histological, angiographic, and other diagnostic imaging findings. The prevalence, clinical characteristics, treatment strategies, in-hospital outcomes, and long-term risk of CE recurrence or major adverse cardiac and cerebrovascular events (cardiac death, fatal arrhythmia, or recurrent thromboembolism) were evaluated. The prevalence of CE was 2.9% (n=52), including 8 (15%) patients with multivessel CE. Atrial fibrillation was the most common cause (n=38, 73%). Only 39% of patients with CE were treated with vitamin K antagonists, and the median international normalized ratio was 1.42 (range, 0.95-1.80). Eighteen of the 30 CE patients with nonvalvular atrial fibrillation had a CHADS 2 score of 0 or 1. When those patients were reevaluated using CHA 2 DS 2 -VASc, 61% were reassigned to a higher risk category. During a median follow-up of 49 months, CE and thromboembolism recurred in 5 atrial fibrillation patients. The 5-year rate of major adverse cardiac and cerebrovascular events was 27.1%. In the propensity score-matched cohorts (n=45 each), Kaplan-Meier analysis showed a significantly higher incidence of cardiac death in the CE group than in the non-CE group (hazard ratio, 9.29; 95% confidence interval, 1.13-76.5; P<0.001). Correspondence to Teruo Noguchi, MD, PhD, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, 565-8565, Japan. E-mail tnoguchi@hsp. The present study was designed to evaluate the prevalence, clinical characteristics, and initial management of CE, and early and late outcomes, as well, in a large consecutive series of patients. We also propose new diagnostic criteria for CE based on histological, angiographic, and other diagnostic imaging findings. Conclusions-Atrial Methods Study Population and PCI ProcedureWe retrospectively analyzed a total of 2135 consecutive patients with AMI from January 2001 to December 2013 in the National Cerebral and Cardiovascular Center AMI database. We excluded 359 patients with a history of previous myocardial infarction (n=241), PCI (n=90), coronary artery bypass grafting (n=18), or both PCI and coronary artery bypass grafting (n=10), resulting in a total of 1776 patients with de novo AMI that were ultimately analyzed in this study (Figure 1). All study patients under...

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Myocardin‐related transcription factor (MRTF)‐A is a Rho signalling‐responsive co‐activator of serum response factor (SRF). Here, we show that induction of MRTF‐A expression is key to pathological vascular remodelling. MRTF‐A expression was significantly higher in the wire‐injured femoral arteries of wild‐type mice and in the atherosclerotic aortic tissues of ApoE−/− mice than in healthy control tissues, whereas myocardin expression was significantly lower. Both neointima formation in wire‐injured femoral arteries in MRTF‐A knockout (Mkl1−/−) mice and atherosclerotic lesions in Mkl1−/−; ApoE−/− mice were significantly attenuated. Expression of vinculin, matrix metallopeptidase 9 (MMP‐9) and integrin β1, three SRF targets and key regulators of cell migration, in injured arteries was significantly weaker in Mkl1−/− mice than in wild‐type mice. In cultured vascular smooth muscle cells (VSMCs), knocking down MRTF‐A reduced expression of these genes and significantly impaired cell migration. Underlying the increased MRTF‐A expression in dedifferentiated VSMCs was the downregulation of microRNA‐1. Moreover, the MRTF‐A inhibitor CCG1423 significantly reduced neointima formation following wire injury in mice. MRTF‐A could thus be a novel therapeutic target for the treatment of vascular diseases.

The presence of CAE predicted future cardiac events in patients with acute MI. Our findings suggest that acute MI patients with CAE are a high-risk subset who might benefit from a pharmacological approach to controlling the coagulation cascade.

BackgroundThe efficacy of pharmacological interventions to prevent sudden arrhythmic death in patients with chronic heart failure remains limited. Evidence now suggests increased ventricular expression of hyperpolarization‐activated cation (HCN) channels in hypertrophied and failing hearts contributes to their arrythmicity. Still, the role of induced HCN channel expression in the enhanced arrhythmicity associated with heart failure and the capacity of HCN channel blockade to prevent lethal arrhythmias remains undetermined.Methods and ResultsWe examined the effects of ivabradine, a specific HCN channel blocker, on survival and arrhythmicity in transgenic mice (dnNRSF‐Tg) expressing a cardiac‐specific dominant‐negative form of neuron‐restrictive silencer factor, a useful mouse model of dilated cardiomyopathy leading to sudden death. Ivabradine (7 mg/kg per day orally) significantly reduced ventricular tachyarrhythmias and improved survival among dnNRSF‐Tg mice while having no significant effect on heart rate or cardiac structure or function. Ivabradine most likely prevented the increase in automaticity otherwise seen in dnNRSF‐Tg ventricular myocytes. Moreover, cardiac‐specific overexpression of HCN2 in mice (HCN2‐Tg) made hearts highly susceptible to arrhythmias induced by chronic β‐adrenergic stimulation. Indeed, ventricular myocytes isolated from HCN2‐Tg mice were highly susceptible to β‐adrenergic stimulation‐induced abnormal automaticity, which was inhibited by ivabradine.ConclusionsHCN channel blockade by ivabradine reduces lethal arrhythmias associated with dilated cardiomyopathy in mice. Conversely, cardiac‐specific overexpression of HCN2 channels increases arrhythmogenicity of β‐adrenergic stimulation. Our findings demonstrate the contribution of HCN channels to the increased arrhythmicity seen in failing hearts and suggest HCN channel blockade is a potentially useful approach to preventing sudden death in patients with heart failure.