Silent Atrial Fibrillation and Cryptogenic Strokes

A new suspected cause of cryptic strokes is “silent atrial fibrillation.” Pacemakers and other implanted devices allow continuous recording of cardiac rhythm for months or years. They have discovered that short periods of atrial fibrillation lasting minutes or hours are frequent and usually are asymptomatic. A meta-analysis of 50 studies involving more than 10,000 patients with a recent stroke found that 7.7% had new atrial fibrillation on their admitting electrocardiogram. In 3 weeks during and after hospitalization, another 16.9% were diagnosed. A total of 23.7% of these stroke patients had silent atrial fibrillation; that is, atrial fibrillation diagnosed after hospital admission. Silent atrial fibrillation is also frequent in patients with pacemakers who do not have a recent stroke. In a pooled analysis of 3 studies involving more than 10,000 patients monitored for 24 months, 43% had at least 1 day with atrial fibrillation lasting more than 5 minutes. Ten percent had atrial fibrillation lasting at least 12 hours. Despite the frequency of silent atrial fibrillation in these patients with multiple risk factors for stroke, the annual incidence of stroke was only 0.23%. When silent atrial fibrillation is detected in patients with recent cryptogenic stroke, anticoagulation is indicated. In patients without stroke, silent atrial fibrillation should lead to further monitoring for clinical atrial fibrillation rather than immediate anticoagulation, as some have advocated.     

心房颤动患者血栓前状态研究

目的 :研究心房颤动 (房颤 )患者血栓前状态相关指标 ,探讨其临床意义。方法 :在慢性房颤患者、具器质性心脏病无房颤患者和健康正常人中 ,测定血浆D 二聚体、血管性血友病因子(vWF)、纤维蛋白原 (Fg)、平均血小板体积 (MPV ) ,以及二磷酸腺苷、肾上腺素、胶原、花生四烯酸诱导的血小板最大聚集率。房颤患者根据是否服阿司匹林分为 2组 :房颤 1组为未服阿司匹林者 (17例 ) ,房颤 2组为服阿司匹林者 (18例 )。具器质性心脏病无房颤且未服用阿司匹林患者 (19例 )为窦性心律组 ,另选 17例正常健康者为对照组。结果 :房颤 1、2组血浆D 二聚体、vWF以及MPV明显高于窦性心律组和对照组 (P <0 0 5～ 0 0 1)。房颤 1、2组血浆Fg明显高于对照组 (P <0 0 5 )。以上指标在房颤 1组和房颤 2组之间的差异无显著性。与房颤 1组比 ,房颤 2组四种诱导剂的血小板最大聚集率均显著降低 ,有极显著性差异 (P <0 0 0 1)。vWF >15 0 %房颤患者Fg更高、左心房内径更大 ,与vWF≤ 15 0 %房颤患者比有显著性差异 (P <0 0 5 )。结论 :房颤患者存在着血栓前状态 ,且不受小剂量阿司匹林的影响 ,这些异常可能与房颤患者心房内血栓形成相关。     

心房颤动患者心房肌钾电流的研究

目的:研究心房颤动患者心房肌内向整流钾电流和乙酰胆碱敏感钾电流的变化,探讨两种离子通道电流变化在心房颤动发生与维持中的作用。方法:应用膜片钳全细胞技术记录并比较19例风湿性心脏病心房颤动患者(心房颤动组)和18例风湿性心脏病窦性心律患者(窦性心律组)心房肌内向整流钾电流和乙酰胆碱敏感钾电流密度的大小。结果:在-60mV～-120mV时,与窦性心律组相比,心房颤动组内向整流钾电流密度绝对值增大,乙酰胆碱敏感钾电流密度绝对值降低。其中在-100mV时,内向整流钾电流密度从窦性心律组的(4.01±1.01)pA/pF(n=18)增大到心房颤动组的(8.94±1.26)pA/pF(n=19,P<0.001);乙酰胆碱敏感钾电流密度从窦性心律组的(24.57±0.77)pA/pF(n=18)降低为心房颤动组的(13.38±1.03)pA/pF(n=19,P<0.001)。结论:心房颤动时,内向整流钾电流密度绝对值增大,乙酰胆碱敏感钾电流密度绝对值降低,两种电流的改变可能与心房颤动的发生和维持有关。     

心房颤动患者左心房内径与左心房血栓发生的关系

目的:探讨心房颤动(房颤)患者左心房内径(LAD)、左心房容积指数(LAVI)与左心房血栓形成的关系及临床意义.方法:选取2006-01至2009-05在新疆维吾尔自治区人民医院住院治疗、资料完整的房颤患者,采用配对研究,按年龄(±5岁)、性别、民族、原发疾病、房颤病程(±6月)配对,共收集了43对房颤患者,根据经胸超声心动图(TTE)或经食管超声心动图(TEE)检查结果分为血栓组及非血栓组.测量左心房内径,并计算左心房容积(LAV)、左心房内径指数(LADI)、左心房容积指数,并进行统计分析.结果:房颤患者血栓组与非血栓组比左心房内径[(58.2±12.1)mm VS(44.6±9.2)mm]、左心房容积[(89.64±18.19)ml vs(47.07±17.44)ml]、左心房内径指数[(0.0821±0.0014)VS(0.0512±0.0009)]、左心房容积指数[(78.44±26.33)ml/m2 VS(49.79±19.67)ml/m2]均高于非血栓组(P均<0.05),差异有统计学意义.结论:左心房增大是房颤患者血栓形成的独立危险因素.     

心房颤动患者血小板活化与左心房血栓形成关系的研究

目的:探讨持续性心房颤动(房颤)患者血小板活化与左心房血栓形成的关系.方法:选择持续性房颤患者(房颤组)84例,窦性心律(窦律组)和正常对照组各20例,其中房颤组39例患者通过经食道超声心动图检查又分为血栓阳性者(22例)和血栓阴性者(17例).所有对象均用流式细胞仪检测全血中血小板膜活化糖蛋白(GP)Ⅱb/Ⅲa水平.结果:左心房内径和血中GPⅡb/Ⅲa水平比较:与正常对照组、窦律组比较,房颤组的左心房内径、GPⅡb/Ⅲa活化阳性血小板的百分率明显增高,差异有统计学意义(P＜0.05).进一步分析结果发现,与正常对照组、窦律组比较,血栓阴性者和血栓阳性者的左心房内径、GPⅡb/Ⅲa活化阳性血小板的百分率明显增高,差异有统计学意义(P＜0.05);且血栓阳性者的左心房内径、GPⅡb/Ⅲa活化阳性血小板的百分率明显高于血栓阴性者,差异有统计学意义(P＜0.05).多元线性回归分析:发现GPⅡb/Ⅲa活化阳性血小板的百分率(t=4.07,P=0.000)是房颤患者左心房血栓形成的独立危险因素,而左心房内径无明确的预测价值(t=1.78,P=0.084).相关性分析:使用直线相关分析方法,分析房颤患者血中GPⅡb/Ⅲa水平同左心房内径的关系,发现GPⅡb/Ⅲa水平同左心房内径两者具有相关性(r=0.57,R2=0.33,P＜0.01).结论:持续性房颤患者存在血小板活化程度增加,且同左心房血栓形成有密切关系.     

Applying the Atrial Fibrillation Guidelines Update to Manage Your Patients With Atrial Fibrillation

Guidelines can be lengthy and complex to apply. We provide a concise summary of important components of outpatient atrial fibrillation management, based on the updated Canadian Cardiovascular Society guidelines. Common questions arising when caring for such patients are addressed, including: what underlying causes should be investigated and treated, how to assess and treat symptoms, how to determine and reduce stroke risk, and when to arrange subspecialty referral. The guidelines emphasize that emergency room visits are rarely necessary and quality of life for most patients with atrial fibrillation can be quite good. The guidelines also clarify that bleeding risk factors should be assessed to identify modifiable issues, rather than as a reason to permanently withhold oral anticoagulant therapy. There is an opportunity to substantially reduce the morbidity and health-system costs related to atrial fibrillation through patient education related to symptom management and adherence to appropriate stroke prevention therapy.     

阵发性心房颤动患者心房肌波长指数的特点

采用波长指数（WLI）=心房功能不应期×（电极间距／心房除极时限）公式计算心房内希氏束（His）、冠状静脉窦口（CSO）、冠状静脉窦中部（CSm）三个部位的WLI，探讨阵发性心房颤动（简称房颤）患者心房肌WLI的特点。观察对象为8例患者，有房颤病史2日～11年。其中6例进行了导管射频消融改良房室结控制快速心室率治疗。8例改良前His、CSO、CSm等处所测的WLI分别为3．95±0．71，1．23±0．26，1．29±0．24cm，6例改良后分别为4．06±0．75，1．43±026，1．32±0．26cm，与对照组相应的三个部位的WLI（5．56±0．71，1．83±0．27，1．92±0．82cm）分别相比，P均＜0．001；改良前、后三个部位的WLI分别相比无显著变化，P＞0．5。认为心房肌WLI／小者容易发生房颤。     

Adverse Events Associated With Electrical Cardioversion in Patients With Acute Atrial Fibrillation and Atrial Flutter

BackgroundWe sought to evaluate safety of electrical cardioversion (ECV) for patients with acute atrial fibrillation (AF) or atrial flutter (AFL) in the emergency department (ED).MethodsThis was an analysis of data from 4 multicentre AF/AFL studies conducted from 2008 to 2019 at 23 large EDs. We included adult patients who received attempts at ECV and who had presented acutely after symptom onset. Staff manually reviewed study and clinical records to abstract data.ResultsWe evaluated 1736 ECV cases with a mean age of 60.1 years and 67.1% male. The overall success of ECV was 90.2% (95% confidence interval 88.7%-91.6%), with 4.9% of patients admitted. ED physicians performed the ECV in 95.2% and provided sedation in 96.5%; 13.9% (12.3%-15.7%) of cases experienced important adverse events that required treatment, and 0.4% were classified as life threatening. Another 5.6% had adverse events that did not require treatment. Logistic regression found that the RAFF-3 study cohort (odds ratio [OR] 2.0), age ≥ 85 years (OR 2.1), coronary artery disease (OR 1.5), midazolam (OR 1.9), and fentanyl (OR 1.5) were associated with important adverse events.ConclusionsThis large evaluation of the safety of ECV for acute AF/AFL in the ED found that while serious adverse events were rare, there were a concerning number of events following sedation that required intervention. Physicians should be aware that older age, coronary artery disease, and fentanyl are associated with higher risks of important adverse events. This study provides more information for shared decision making discussions with patients when choosing between drug-shock and shock-only cardioversion strategies.