Variant rs2200733 on Chromosome 4q25 Confers Increased Risk of Atrial Fibrillation: Evidence From a Meta‐Analysis

Variant rs2200733 on Chromosome 4q25 Confers Increased Risk . Introduction: Several genome‐wide association studies have identified rs2200733, a single‐nucleotide polymorphism (SNP) at 4q25 to be the most common chromosomal variant present in patients with atrial fibrillation (AF). We aimed to explore the association of rs2200733 with AF through a systematic review and meta‐analysis. Method: An extensive literature search was performed on PubMed, and other databases using the key words “genetics” and “AF.” Seven case‐control studies evaluating the association via multivariate analysis were identified including a total of 83,335 subjects (10,546 with AF, 72,789 referent individuals without AF). Meta‐analytic estimates were derived using random effects models. Potential sources of heterogeneity were examined in sensitivity analyses, and publication biases were estimated. Result: At pooled analysis, there was a strong independent association between the variant rs2200733 and the risk of AF (OR 1.89 [95% CI 1.62–2.16], P < 0.001). Minor allelic frequencies for SNP rs22000733 were significantly more prevalent in AF population than non‐AF. Metaregression results revealed that country of descent (logOR 0.38, P = 0.45) or site of study (logOR: ?0.16, P = 0.41) did not moderate the overall effect size. Conclusion: Variant rs2200733 on chromosome 4q25 independently confers increased risk of AF. This finding will aid in improving our understanding of AF pathophysiology, risk prediction, and stratification of treatment strategy. (J Cardiovasc Electrophysiol, Vol. 24, pp. 155‐161, February 2013)     

Prolonged Atrium Electromechanical Interval Is Associated with Stroke in Patients with Atrial Fibrillation After Catheter Ablation

Electromechanical Interval and Strokes After Ablations of AF . Introduction: Atrial fibrillation (AF) is associated with increased risk of embolic stroke. Catheter ablation of AF provides an effective therapy for patients with symptomatic and drug‐refractory AF. The aim of this study was to evaluate whether the atrial electromechanical interval is useful in identifying patients at risk of stroke after successful catheter ablation. Methods and Results: A total of 279 AF patients who received catheter ablation and showed no evidence of recurrences were enrolled. Electromechanical interval (PA–PDI) was determined as the time interval from the initiation of P wave deflection to the peak of mitral inflow A wave on pulse wave Doppler imaging. The PA–PDI interval was measured for each patient after the 3‐month blanking period of catheter ablation. The clinical endpoint was the occurrence of ischemic stroke. During the follow‐up of 46.5 ± 17.2 months, 6 patients suffered from ischemic strokes. Patients with strokes had higher CHA₂DS₂–VASc scores and longer PA–PDI intervals (138.7 ± 12.4 ms vs 161.2 ± 7.7 ms, P value < 0.001) compared to those without strokes. At a cutoff point of 150 ms identified by ROC curve, the positive and negative predictive values of the PA–PDI interval to predict stroke were 86.7% and 100%, respectively. The PA–PDI interval improved the predictive performance of the CHA₂DS₂–VASc score, and the area under the ROC curve increased from 0.75 to 0.85. Conclusions: Our results suggest that the PA–PDI interval is a useful tool to identify patients with high risk of stroke after successful catheter ablation of AF. (J Cardiovasc Electrophysiol, Vol. 24, pp. 375‐380, April 2013)     

Epicardial Adipose Tissue Is Associated With Left Atrial Dysfunction in People Without Obstructive Coronary Artery Disease or Atrial Fibrillation

Background

Epicardial adipose tissue (EAT) is a metabolically active visceral fat depot. Although EAT volume is associated with the incidence and burden of atrial fibrillation (AF), its role in subclinical left atrial (LA) dysfunction is unclear. This study aims to evaluate the relationships between EAT volumes, LA function, and LA global longitudinal strain.

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.     

心房颤动患者体表心电图QT间期的变化

探讨心房颤动(简称房颤)患者体表心电图QT间期的变化。入选81例房颤患者和71例对照者,测量Ⅰ导联和V2导联QT间期,根据Bazett公式计算QTc。结果:窦性心律时V2导联QT间期可测量性略高于Ⅰ导联,而房颤时相反。V2导联测得的QTc比Ⅰ导联长。房颤组与对照组比较,窦性心律时Ⅰ导联和V2导联的QTc两组间均无明显差异;房颤发作时Ⅰ导联QTc较对照组延长(429.01±43.08msvs408.50±31.93ms,P<0.05);V2导联QTc较对照组也延长(444.45±33.16msvs414.82±25.57ms,P<0.05)。房颤组房颤发作时与窦性心律时的自身对照比较,V2导联的QTc也延长(448.63±31.59msvs426.22±29.08ms,P<0.05)。结论:房颤患者在房颤发作时QTc延长,而房颤患者窦性心律时QTc与对照组无差异。     

应用多层螺旋计算机断层摄影术技术对比分析心房颤动及非心房颤动患者左心耳的形态学特征

目的探讨多层螺旋计算机断层摄影术(Multislice spiral CT,MSCT)对评价心房颤动(房颤)及非房颤患者左心耳形态学的临床应用价值.方法对入选的86例患者分为房颤组44例为拟行导管消融治疗的阵发性房颤患者,对照组42例为无房颤的患者.所有患者经MSCT肺静脉成像检查,进行三维容积重建.测量左心耳容积、左心耳口长短径直径、左心耳与冠状动脉左回旋支的关系、左心耳嵴的长度及宽度.结果房颤组患者左心房容积(119.8±33.4)ml、左心耳容积(10.1±4.8)ml、左心耳口面积(293.2±113.7)mm2、左心耳口长短径(24.3±5.3)mm、(15.6±4.4)mm均显著大于对照组,分别为(89.6±29.2)ml,(7.5±3.1)ml,(221.5±87.6)mm2,(20.8±3.8)mm及(13.0±3.3)mm,有极显著性差异(P＜0.005).房颤组患者左心耳口面积自54.0 mm2～502.4 mm2不等,对照组为111.0 mm2～566.6 mm2不等.而两组中左心耳嵴的长度及宽度、左心耳基部同冠状动脉左回旋支的距离没有显著差别.结论在房颤患者中,除了左心房的增大,左心耳容积及左心耳口面积也显著地增大,提示左心耳形态学的改变同房颤的发生密切相关.房颤患者左心耳口面积相差很大,术前评价左心耳口对选择封堵器及其型号很有帮助.另一方面,左心耳非常接近冠状动脉回旋支,基于左心耳基部消融时,应谨慎选择消融策略以避免损伤回旋支.MSCT可作为测量及评价左心房、左心耳相关指标,明确左心耳周围组织结构的有效检查手段.     

Outcome of Ablation for Sustained Focal Atrial Tachycardia in Patients With and Without a History of Atrial Fibrillation

Objectives: The aim of this study was to determine the long-term results of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.Methods: A history of atrial fibrillation was documented in 25 of 111 patients (23%) with focal atrial tachycardias. We studied the results of focal ablation during a follow-up of 27 ± 22 months.Results: Enlargement of left atrium (Odds ratio 2.99) and septal origin of the atrial focus (Odds ratio 5.68) were independent predictors of coexisting atrial fibrillation. Patients with a septal origin of the focal atrial tachycardia were older (62 vs. 54 years) and had a higher rate of structural heart disease than patients with a non-septal site of origin (51 vs. 29%). A higher rate of atrial fibrillation was found in patients with anteroseptal (56%), midseptal (50%) and posteroseptal (36%) atrial tachycardias than in patients with focal atrial tachycardias arising from the crista terminalis (9%), the tricuspid (12%) and mitral annulus (0%), the ostia of thoracic veins (17%) and other right atrial (27%) and left atrial free wall sites (10%). During the follow-up, atrial fibrillation was documented in 3% of patients without preexisting atrial fibrillation. In patients with focal atrial tachycardia and a history of atrial fibrillation, at least one episode of atrial fibrillation was documented during follow-up in 64% of patients, but 60% of patients reported marked symptomatic improvement.Conclusion: An increased rate of coexisting atrial fibrillation was found in patients with a septal origin of focal atrial tachycardia. Ablation of the focal atrial tachycardia may eliminate both arrhythmias, but patients with a history of atrial fibrillation may still be prone to recurrences of atrial fibrillation after focal ablation.     

Circadian Rhythms of Atrioventricular Conduction Properties in Chronic Atrial Fibrillation With and Without Heart Failure

Objectives. We examined the circadian variations in atrioventricular (AV) conduction properties during atrial fibrillation (AF) by a technique based on the Lorenz plot of successive ventricular response (VR) intervals and analyzed their relations with clinical features.Background. The VR interval in chronic AF shows circadian variation, which is attenuated in patients with an increased risk of death. Although the VR interval is determined by the dynamic processes in the AV node randomly stimulated by rapid atrial activity, the circadian variations of the AV conduction properties related to this mechanism are unknown.Methods. In 48 patients with chronic AF, Lorenz plots were generated on overlapping sequential segments of 512 VR intervals in 24-h ambulatory electrocardiograms. For each scatter plot, the 1.0-s intercept of the lower envelope (LE_1.0) of the plot and the degree of scatter above the envelope (root mean square difference from the envelope [scattering index]) were measured for estimating AV node refractoriness and concealed AV conduction, respectively.Results. In all patients, a significant circadian rhythm was observed for the average VR interval, LE_1.0and scattering index, with an acrophase occurring at night. The mesor, amplitude and acrophase of LE_1.0and the scattering index closely and independently correlated with the corresponding rhythm variables of the average VR interval (partial r²0.98, 0.86 and 0.68 for LE_1.0and 0.98, 0.92 and 0.92 for scattering index). The amplitudes of these measures were lower in patients with congestive heart failure (CHF) even after adjustment for the effects of age, duration of AF, medications, left atrial diameter and blood pressure (p < 0.01 for all).Conclusions. These results suggest that 1) both AV node refractoriness and the degree of concealed AV conduction during AF may show a circadian rhythm; 2) the circadian rhythms of these properties may independently contribute to the circadian variation of the VR interval; and 3) these circadian rhythms may be attenuated in patients with CHF.