Prevalence of oral anticoagulation in atrial fibrillation

OBJECTIVES:

Atrial fibrillation is the most common sustained arrhythmia and is associated with poor outcomes, including stroke. The ability of anticoagulation therapy to reduce the risk of stroke has been well established; however, the prevalence of anticoagulation therapy use in the Public Health System is unknown. The aim of this study is to evaluate both the prevalence of anticoagulation therapy among patients with atrial fibrillation and the indications for the treatment.

METHODS:

In this cross-sectional study, we included consecutive patients who had atrial fibrillation documented by an electrocardiogram performed between September 2011 and March 2012 at a university hospital of the Public Health System. The variables analyzed included the risk of a thromboembolic event and/or bleeding, the use of antiplatelet or anticoagulation therapy, the location where the electrocardiogram report was initially reviewed and the specialty of the physician who initially reviewed it.

RESULTS:

We included 162 patients (mean age 68.9 years, 56% men). Hypertension (90.1%), heart failure (53.4%) and stroke (38.9%) were the most prevalent diseases found. Only 50.6% of the patients knew that they had atrial fibrillation. Regarding the use of therapy, only 37.6% of patients classified as high risk according to the CHADS2 scores and 35.5% according to the CHA2DS2VASc used oral anticoagulation. A presumptive diagnosis of heart failure and the fact that the electrocardiogram was evaluated by a cardiologist were the only independent predictors of the use of anticoagulants.

CONCLUSIONS:

Our study found a low prevalence of oral anticoagulation therapy among patients with atrial fibrillation and an indication for stroke prophylaxis for the use of this therapy, including among those with high CHADS2 and CHA2DS2VASc scores.     

Nkx2.5在肺血减少型先天性心脏病右室流出道心肌中突变及表达的意义

目的 观察Nkx2.5基因在肺血减少型先天性心脏病（CHD）患者中的突变及表达变化,探讨Nkx2.5基因在右室流出道梗阻发生中的分子调控机制.方法 选取2012年5月—2013年5月蚌埠医学院第一附属医院与安徽省立儿童医院心脏外科收治的56例肺血减少型CHD患者为实验组,同期收治的63例室间隔缺损患者为对照组.收集所有患者术前外周静脉血5 ml,采用PCR结合DNA测序技术对Nkx2.5基因的外显子进行序列检测,观察有无Nkx2.5基因突变;留取术中右室流出道肥厚心肌组织0.5 cm ×0.5 cm ×0.5 cm,提取心肌组织RNA,应用实时荧光定量PCR技术检测心肌中Nkx2.5基因mRNA的表达情况,分析Nkx2.5基因与肺血减少型CHD的关系.结果 实验组与对照组外周静脉血中均未检测出基因突变,实验组心肌组织Nkx2.5基因mRNA表达水平较对照组显著降低,差异有统计学意义（P＜0.01）.结论 Nkx2.5基因突变可能与多因素有关;肺血减少型CHD的发生可能与心肌组织中Nkx2.5基因表达下降有关.     

Warfarin doses for anticoagulation therapy in elderly patients with chronic atrial fibrillation

OBJECTIVE:

Anticoagulation is a challenge for the prophylaxis of thromboembolic events in elderly patients with chronic atrial fibrillation. Stable anticoagulation is defined as the time within >70% of the therapeutic range. However, the dosage required to achieve stable anticoagulation remains unknown. The aim of this study was to analyze the warfarin dose necessary for the maintenance of stable oral anticoagulation therapy in elderly patients.

METHODS:

We analyzed 112 consecutive outpatients with atrial fibrillation who were ≥65 years of age, had received anticoagulation therapy with warfarin for more than 1 year and had a stable international normalized ratio between 2.0 and 3.0 for ≥6 months. The international normalized ratio was measured in the central laboratory using the traditional method.

RESULTS:

The patients were stratified according to the following age groups: <75 or ≥75 years and <80 or ≥80 years. The mean daily doses of warfarin were similar for patients <75 or ≥75 years (3.34±1.71 versus 3.26±1.27 mg/day, p = 0.794) and <80 or ≥80 years (3.36±1.49 versus 3.15±1.23 mg/day, p = 0.433). In 88 (79%) patients, the daily warfarin dose was between 2 and 5 mg/day; in 13 (11%) patients, the daily warfarin dose was <2.0 mg/day; and in 11 (10%) patients, the daily warfarin dose was >5.0 mg/day. The correlation between the daily warfarin dose and the international normalized ratio was 0.22 (p = 0.012).

CONCLUSION:

Stable anticoagulation was achieved in 80% of patients who received doses of 2 to 5 mg/day of warfarin, and the mean daily dose was similar across the age groups analyzed.     

Predictors of the risk of falls among elderly with chronic atrial fibrillation

OBJECTIVES:

Though elderly persons with chronic atrial fibrillation have more comorbidities that could limit indications for the chronic use of anticoagulants, few studies have focused on the risk of falls within this particular group. To evaluate the predictors of the risk of falls among elderly with chronic atrial fibrillation, a cross-sectional, observational study was performed.

METHODS:

From 295 consecutive patients aged 60 years or older with a history of atrial fibrillation who were enrolled within the last 2 years in the cardiogeriatrics outpatient clinic of the Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, 107 took part in this study. Their age was 77.9±6.4 years, and 62 were female. They were divided into two groups: a) no history of falls in the previous year and b) a history of one or more falls in the previous year. Data regarding the history of falls and social, demographic, anthropometric, and clinical information were collected. Multidimensional assessment instruments and questionnaires were applied.

RESULTS:

At least one fall was reported in 55 patients (51.4%). Among them, 27 (49.1%) presented recurrent falls, with body lesions in 90.4% and fractures in 9.1% of the cases. Multivariate logistic regression showed that self-reported difficulty maintaining balance, use of amiodarone, and diabetes were independent variables associated with the risk of falls, with a sensitivity of 92.9% and a specificity of 44.9%.

CONCLUSION:

In a group of elderly patients with chronic atrial fibrillation who were relatively independent and able to attend an outpatient clinic, the occurrence of falls with recurrence and clinical consequences was high. Difficulty maintaining balance, the use of amiodarone and a diagnosis of diabetes mellitus were independent predictors of the risk for falls. Thus, simple clinical data predicted falls better than objective functional tests.     

Score for atrial fibrillation detection in acute stroke and transient ischemic attack patients in a Brazilian population: The acute stroke atrial fibrillation scoring system

OBJECTIVE:

Atrial fibrillation is a common arrhythmia that increases the risk of stroke by four- to five-fold. We aimed to establish a profile of patients with atrial fibrillation from a population of patients admitted with acute ischemic stroke or transient ischemic attack using clinical and echocardiographic findings.

METHODS:

We evaluated patients consecutively admitted to a tertiary hospital with acute ischemic stroke or transient ischemic attack. Subjects were divided into an original set (admissions from May 2009 to October 2010) and a validation set (admissions from November 2010 to April 2013). The study was designed as a cohort, with clinical and echocardiographic findings compared between patients with and without atrial fibrillation. A multivariable model was built, and independent predictive factors were used to produce a predictive grading score for atrial fibrillation (Acute Stroke AF Score-ASAS).

RESULTS:

A total of 257 patients were evaluated from May 2009 to October 2010 and included in the original set. Atrial fibrillation was diagnosed in 17.5% of these patients. Significant predictors of atrial fibrillation in the multivariate analysis included age, National Institutes of Health Stroke Scores, and the presence of left atrial enlargement. These predictors were used in the final logistic model. For this model, the area under the receiver operating characteristic curve was 0.79. The score derived from the logistic regression analysis was The model developed from the original data set was then applied to the validation data set, showing the preserved discriminatory ability of the model (c statistic = 0.76).

CONCLUSIONS:

Our risk score suggests that the individual risk for atrial fibrillation in patients with acute ischemic stroke can be assessed using simple data, including age, National Institutes of Health Stroke Scores at admission, and the presence of left atrial enlargement.     

家族性心房颤动与基因突变的研究进展

根据心房颤动(简称房颤)的遗传性和家族聚集性,可分为家族性房颤和非家族性房颤.房颤的发生机制尚未明确,但研究显示基因突变是其致病因素之一.近年来通过对家族性房颤进行基因遗传性研究,已经发现部分离子通道和非离子通道致病基因,现就以上领域的研究进展予以综述.     

心房颤动中间质纤维化的分子生物学研究

心房颤动是临床上最常见的一种心律失常,临床及实验均发现心房颤动中心房存在明显纤维化。心房纤维化被认为是发生心房颤动的结构基础,改变了心房的结构进而使心房功能受损。心房颤动心房纤维化的发生机制尚未完全明确。目前对心房颤动心房纤维化结构改变的研究发现：一系列细胞因子特别是肾素-血管紧张素系统、转化生长因子-β1、基质金属蛋白酶等在心房颤动及纤维化的发生、维持中作用明显。该文探讨了心房颤动心房纤维化的分子生物学发生机制及研究进展。     

ECG characterization of paroxysmal atrial fibrillation: parameter extraction and automatic diagnosis algorithm

Paroxysmal atrial fibrillation (PAF) is one of the most common heart arrhythmias. It is very difficult to detect unless an explicit Atrial Fibrillation episode occurs during the exploration. The present paper describes a number of low level parameters extracted from ECG traces where no Atrial Fibrillation process is present. The ability of this parameter set to characterize PAF patients is studied and discussed. Based on these parameters a modular automatic classification algorithm for PAF diagnosis is developed and evaluated.     

Alternative energy sources for surgical treatment of atrial fibrillation in patients undergoing mitral valve surgery: microwave ablation vs cryoablation

The study aim was to compare maze outcomes using microwave ablation or cryoablation in patients with mitral disease and atrial fibrillation (AF). Between 1999 and 2005, 340 patients underwent mitral valve surgery and concomitant maze procedure involving either microwave ablation (n=96, MW group) or cryoablation (n=244, Cryo group). Mean age at operation was 50.0±12.5 yr. Follow-up period was 46.1±28.2 months. The Cryo group showed a longer aortic clamping time than the MW group (P=0.005). There were no differences in operative mortality and morbidity rates. The unadjusted 5-yr AF free rate was 61.3±1.2% in the MW group and 79.9±3.2% in the Cryo group (P=0.089). After adjustment, the MW group only showed a tendency toward more frequent AF recurrence than the Cryo group (Hazard ration 1.66, 95% confidence interval 0.89 to 3.07). Multivariate analysis revealed that older patient age (P<0.001) and greater left atrial size (P<0.001) were independent risk factors for AF recurrence. Although the use of microwave ablation results in shorter aortic clamping time, it has a tendency toward more frequent late AF recurrence than with cryoablation.     

Sociodemographic,behavioral, and clinical factors associated with low atrial fibrillation knowledge among older adults with atrial fibrillation: The SAGE-AF study

BackgroundManagement of AF requires patient engagement in disease management which requires adequate knowledge about AF.ObjectiveTo identify the patient characteristics associated with low AF knowledge among older adults with AF.MethodsThe SAGE-AF cohort enrolled adults aged ≥65 diagnosed with AF in 2016?2018. Patient characteristics associated with low AF knowledge (<6/8 JAKQ items correct) were examined using multivariable adjusted logistic regression models.ResultsParticipants (N = 950) were on average 74 years old (SD: 6.7), 50 % female, and 87 % non-Hispanic white. The average JAKQ score was 68.7 (SD: 17.1), and 78 % had low AF knowledge. Participants aged ≥ 75 (OR: 1.55, 95 % CI: 1.03, 2.33), without a college degree (OR: 0.46, 95 % CI: 0.32, 0.65), cognitively impaired (OR: 1.72, 95 % CI: 1.15, 2.58), with a history of anxiety (OR: 1.76, 95 % CI: 1.09, 2.83), myocardial infarction (OR: 1.82, 95 % CI: 1.08, 3.07), and heart failure (OR: 1.84, 95 % CI: 1.16, 2.91) were more likely to have low AF knowledge.Practice implicationsCharacteristics available in the electronic medical record may identify patients at risk for low AF knowledge. Formal assessment of AF knowledge may identify areas of weakness and allow for targeted education.     

New parameters for left ventricular function in atrial fibrillation: based on the relationship between RR interval and performance

This study was designed to obtain new parameters representing left ventricular (LV) function independent of irregular RR intervals in atrial fibrillation (AF). AF patients were divided into Normal (n=9) and LV Dysfunction (n=9) groups. The relations between LV outflow peak ejection velocity (Vpe) and preceding (RR-1) or prepreceding RR intervals (RR-2) were obtained using logarithmic equations, from which the squared correlation coefficient (r2), slope, Vpe at RR-1 or RR-2=1 sec (Vpe-1), and the ratio of slope to Vpe-1 (Slope/Vpe-1) were calculated. Among the parameters between RR-1 and Vpe, Slope/Vpe-1 was higher in LV Dysfunction group than in Normal group (p=0.05). When only coordinates with RR-1 from 0.6 to 1 sec were included, Slope/Vpe-1 (p=0.001) was higher in LV Dysfunction group than in Normal group. Among the parameters between RR-2 and Vpe, Slope/Vpe-1, slope, and r2 were different between the two groups. In multivariate analysis, Slope/Vpe-1 between RR-2 and Vpe was only independent parameter. However, Slope/Vpe-1 between RR-1 and Vpe in the coordinates with RR-1 from 0.6 to 1 sec had the highest discriminating power. New parameters derived from the relations between RR intervals and LV performance might be useful to evaluate LV function quantitatively in AF.     

螺内酯对高甲状腺素诱导的兔心房颤动和心房重构的影响

目的:探讨螺内酯对高甲状腺素诱导的兔心房颤动(AF)和心房重构的影响。方法:新西兰兔33只随机分为3组:正常对照组(C)、高甲状腺素组(H)和螺内酯组(S)。H和S组腹腔注射甲状腺素4周建立兔甲亢性AF模型,之后,S组给予螺内酯灌胃2周。给药结束后,通过心内电生理高频刺激诱发AF,计算AF诱发率,测量心房有效不应期(AERP)。荧光定量PCR测定L型钙通道亚基(Cav1.2)、钾通道相关亚基(Kv1.5、Kv4.3)和缝隙连接蛋白(Cx40、Cx43)的mRNA表达,Western blot和免疫组化测定上述指标的蛋白表达。结果:螺内酯降低AF诱发率。H组和S组的AERP无明显差异(P0.05)。S组Cav1.2蛋白表达水平明显高于H组(P0.05)。S组Kv1.5的mRNA和蛋白表达水平均明显低于H组(P0.05),S组Kv4.3的蛋白表达水平显著低于H组(P0.05)。S组Cx43的mRNA表达水平明显低于H组(P0.01),S组Cx40的蛋白表达水平显著低于H组(P0.05)。结论:螺内酯可降低高甲状腺素所致的AF诱发率,改善其引起的心房重构。     

高频刺激左心房引起家兔慢性心房颤动

目的： 探讨以高频率起搏刺激左心房建立家兔慢性心房颤动模型的方法。 方法： 20只家兔随机分为实验组及对照组，对照组为假手术组，植入起搏器但不起搏，实验组10只家兔予开胸植入高频率起搏器(1 000 次/分)刺激左心房30 d，术后定期监测起搏、心房颤动的发生情况、房颤时心室率变化，同时测定起搏前及房颤发生后心房有效不应期（AERP）的变化。 结果： 实验组均完成了实验，术后第7 d，7只（70％）兔发生了房颤，2周时共有8只（80％）发生了房颤并能稳定维持（与对照组比较，P＜0.01），30 d时仍示房颤，其余2只兔至30 d时仍呈起搏心律，对照组则未发生任何心律失常情况。心房颤动时的心室率最初明显增快（P＜0.05），随后有所降低（P＜0.05），但仍高于基础心室率（P＜0.05）。AERP缩短，AERP频率适应不良，与基础状态相比有显著意义。 结论： 长期高频率起搏刺激家兔左心房是建立慢性房颤模型的有效方法。     

口服胺碘酮和心律平治疗心房纤颤疗效比较

目的:探讨口服胺碘酮和心律平(普罗帕酮)治疗心房纤颤的效果。方法:采用随机对照试验比较两者在转复房颤,维持窦性节律及不良反应上的情况。结果:两者在心房纤颤的转复率上无明显差异,而胺碘酮在维持窦性节律及安全性方面优于心律平。结论:胺碘酮在治疗心房纤颤,维持窦性节律比心律平有明显的优越性且安全,值得在临床是推广。