Pre-operative left atrial strain predicts post-operative atrial fibrillation in patients undergoing aortic valve replacement for aortic stenosis

Post-operative atrial fibrillation (AF) is a common and serious complication in patients undergoing aortic valve replacement (AVR). Speckle tracking echocardiography (STE) has recently enabled the quantification of longitudinal myocardial left atrial (LA) deformation dynamics. Our aim was to investigate LA preoperative mechanical function in patients undergoing AVR for aortic stenosis using STE and determine predictors of post-operative AF. 76 patients with aortic stenosis in sinus rhythm, undergoing AVR, were prospectively enrolled. Conventional echocardiographic parameters, and peak atrial longitudinal strain (PALS) were measured in all subjects the day before surgery. PALS values were obtained by averaging all segments in the 4- and 2-chamber views (global PALS). All patients received biological valve prostheses and a standard postoperative care. Postoperative AF occurred in 15 patients (19.7 %). On univariate analysis among all clinical and echocardiographic variables, global PALS showed the highest diagnostic accuracy (HR 6.55 p < 0.0001; AUC of 0.89) with a cut-off value <16.9 %, having sensitivity and specificity of 86 and 91 %, respectively, in predicting postoperative AF. LA volume indexed and E/e’ ratio had lower diagnostic accuracy (AUC 0.76 and 0.51, respectively). On multivariate analysis global PALS remains a significant predictor of postoperative AF (p < 0.0001). STE analysis of LA myocardial deformation is considered a promising tool for the evaluation of LA subclinical dysfunction in patients undergoing AVR, giving a potentially better risk stratification for the occurrence of postoperative AF.     

经食管超声心动图对心房颤动时左心耳血流动力学的研究

目的 研究心房颤动（房颤）时左心耳血流动力学的变化及临床价值。方法 使用多平面经食管超声心动图记录并分析74例房颤患者的左心耳图像、血流频谱及其他相应指标。结果 房颤患者的左心耳最大容积（Vmax-LAA)、左心耳最小容积（Vmin-LAA）均大于窦性心律对照组，左心耳射血分数EF-LAA、左心耳的最大在正向血流速度（V-LAA^ 、最大负向血流速度（V-LAA^-）均小于窦律对照组。其中风湿性心脏病轻度二尖瓣狭窄组与重度二尖瓣狭窄组的上述指标与非风湿性心脏病房颤组均有明显差异，而风湿性心脏病二组间的上述指标无明显差异。Ⅲ型左心耳血流频谱易伴随着较严重的左心耳、左心房的自发性回声（SEC）及血栓形成。结论 多平面经食管超声技术可有效评价房颤时左心耳血流动力学，尤其对房颤早期左房血流动力学及左心房SEC及血栓的早期预防有较实际的应用价值。     

Clinical significance of the atrial fibrillation threshold in patients with paroxysmal atrial fibrillation

AF threshold and the other electrophysiological parameters were measured to quantify atrial vulnerability in patients with paroxysmal atrial fibrillation (PAF, n = 47), and those without AF (non-PAF, n = 25). Stimulations were delivered at the right atrial appendage with a basic cycle length of 500 ms. The PAF group had a significantly larger percentage of maximum atrial fragmentation (%MAF, non-PAF: mean +/- SD = 149 +/- 19%, PAF: 166 +/- 26%, P = 0.009), fragmented atrial activity zone (FAZ, non-PAF: median 0 ms, interquartile range 0-20 ms, PAF: 20 ms, 10-40 ms, P = 0.008). Atrial fibrillation threshold (AF threshold, non-PAF: median 11 mA, interquartile range 6-21 mA, PAF: 5 mA, 3-6 mA, P < 0.001) was smaller in the PAF group than in the non-PAF group. Sensitivity, specificity, and positive predictive value of electrophysiological parameters were as follows, respectively: %MAF (cut off at 150%, 78%, 52%, 76%), FAZ (cut off at 20 ms, 47%, 84%, 85%), AF threshold (cut off at 10 mA, 94%, 60%, 81%). There were no statistically significant differences between the non-PAF and PAF groups in the other parameters (effective refractory period, interatrial conduction time, maximum conduction delay, conduction delay zone, repetitive atrial firing zone, wavelength index), that were not specific for PAF. In conclusion, the AF threshold could be a useful indicator to evaluate atrial vulnerability in patients with AF.     

Dual-site right atrial pacing increases left atrial appendage flow in patients with sick sinus syndrome and paroxysmal atrial fibrillation

BACKGROUND: Dual-site right atrial pacing has been proposed as a promising concept for prevention of paroxysmal atrial fibrillation (PAF). Effects of this pacing configuration on left atrial appendage (LAA) flow and transmitral flow may be of prognostic and hemodynamic relevance. This study aims to characterize acute changes in left atrial flow depending on dual-site right atrial pacing. METHODS: In 12 patients (66 +/- 8.8 years, 4 women) with PAF and sinus bradycardia a pacemaker with a right atrial dual-site lead configuration (right atrial lateral and coronary sinus ostium) was implanted. Flow velocities in the left pulmonary vein (LPV), LAA, and across the mitral valve were assessed by transesophageal echocardiography and compared during sinus rhythm (SR) and dual-site (DS) pacing. RESULTS: Dual-site pacing resulted in higher maximum (SR: 0.57 m/s; pacing: 0.77 m/s; P < 0.02) and mean (SR: 0.33 m/s; DS: 0.47 m/s; P < 0.01) LAA emptying flow when compared with SR. The passive transmitral flow component (maximum E-wave velocity) was lower during dual-site pacing (SR: 0.53 m/s vs DS: 0.44 m/s, P < 0.02). The E/A ratio tended to be lower during dual-site pacing (SR: 1.21 vs DS: 1.01, P = 0,10). LPV flow velocities during SR and DS pacing did not differ. CONCLUSION: DS right atrial stimulation in patients with PAF increases the LAA emptying flow velocity and shifts the transmitral flow pattern towards a lower passive component when compared with sinus rhythm. The change in LAA flow may contribute to a lower incidence of thromboembolism and merits further investigation.     

Endothelial function in patients with atrial fibrillation

Abstract

Atrial fibrillation (AF) is the most common heart arrhythmia and is associated with poor outcomes. The adverse effects of AF are mediated through multiple pathways, including endothelial dysfunction, as measured by flow-mediated dilatation. Flow-mediated dilatation has demonstrated endothelial dysfunction in several conditions and is associated with poor outcomes including mortality, yet can be improved with medical therapy. It is thus a useful tool in assessing endothelial function in patients. Endothelial dysfunction is present in patients with AF and is associated with poor outcomes. These patients are generally older and have other co-morbidities such as hypertension, hypercholesterolaemia and diabetes. The precise process by which AF is affiliated with endothelial damage/dysfunction remains elusive. This review explores the endothelial structure, its physiology and how it is affected in patients with AF. It also assesses the utility of flow mediated dilatation as a technique to assess endothelial function in patients with AF.

• Key Messages

• Endothelial function is affected in patients with atrial fibrillation as with other cardiovascular conditions.

• Endothelial dysfunction is associated with poor outcomes such as stroke, myocardial infarction and death, yet is a reversible condition.

• Flow-mediated dilatation is a reliable tool to assess endothelial function in patients with atrial fibrillation.

• Patients with atrial fibrillation should be considered for endothelial function assessment and attempts made to reverse this condition.

     

Managing anticoagulation in patients with atrial fibrillation

Patients with nonvalvular atrial fibrillation have an increased risk of cerebral thromboembolism. Oral anticoagulation therapy, however, provides primary and secondary stroke prevention in these patients. Here, update your knowledge of warfarin initiation, titration, monitoring, and adjustment.     

Left atrial booster-pump function as a predictive parameter for new-onset postoperative atrial fibrillation in patients with severe aortic stenosis

Postoperative atrial fibrillation (POAF) is associated with increased risk of embolic events and heart failure, but its associated factors remains unknown. Left atrial (LA) subclinical mechanical dysfunction caused by the acute stress of surgery may be clinically manifested as POAF. The purpose of our study was therefore to test the hypothesis that preoperative LA subclinical myocardial dysfunction is a potential predictor of development of POAF in patients with aortic stenosis (AS). We studied 27 patients with severe AS undergoing aortic valve replacement (AVR) with left ventricular (LV) ejection fraction of 63 ± 11 %. All patients were in sinus rhythm and had no history of atrial fibrillation (AF). LA reservoir (SR-LAs), conduit (SR-LAe), and booster-pump (SR-LAa) functions were determined as the averaged global LA speckle-tracking longitudinal strain rates from apical four- and two-chamber views. POAF, defined as any episode of AF within 30-day after AVR, was observed in 15 patients (56 %). There were no differences in clinical characteristics, LA and LV volumes, and global LV function between patients with and without POAF. Multivariate logistic regression analysis identified SR-LAa as the only independent predictor of POAF. Furthermore, SR-LAa >0.79 s^?1 predicted POAF with 60 % sensitivity, 92 % specificity, and area under the curve of 0.828 (p < 0.0001). Of the 15 patients with POAF, one developed paroxysmal AF during long-term follow-up. In conclusions, SR-LAa helped to detect subtle LA booster-pump dysfunction and was associated with new-onset POAF in patients with severe AS. These findings may be useful for risk stratification and management of such patients.     

Catheter ablation vs. amiodarone plus losartan for prevention of atrial fibrillation recurrence in patients with paroxysmal atrial fibrillation

Background  Although amiodarone plus angiotensin II receptor blockers (ARBs) and catheter ablation may improve sinus rhythm maintenance of paroxysmal atrial fibrillation (AF), their clinical efficacies have not been compared. This prospective cohort study was designed to compare clinical efficacy of catheter ablation and amiodarone plus losartan on sinus rhythm maintenance in patients with paroxysmal AF.
Materials and methods  A total of 240 patients with paroxysmal AF were assigned to four groups. CPVA group ( n =  60) was treated with circumferential pulmonary vein ablation (CPVA), SPVI group ( n  = 60) with segmental pulmonary vein isolation, AMIO group ( n  = 60) with amiodarone and AMIO + LO group ( n  = 60) with amiodarone plus losartan. The endpoint was documented recurrence of AF > 30 s by Holter or conventional 12-lead ECG in the 1-year follow-up period.
Results  During 12 months of follow-up, the primary end point was reached in 28 patients in CPVA group, 14 patients in SPVI group, 25 patients in AMIO group and 13 patients in AMIO + LO group, respectively. The sinus rhythm in SPVI and AMIO + LO group were significant higher than that in CPVA and AMIO group ( P  < 0·01 and 0·025), and no difference between CPVA and AMIO group. The maintenance rate of sinus rhythm in SPVI group was similar to that in AMIO + LO group.
Conclusions  This study demonstrates that segmental pulmonary vein isolation in preventing AF recurrence is similar to amiodarone plus losartan, but it is superior to CPVA and amiodarone alone in patients with paroxysmal AF. Larger multicentre studies are needed to confirm its long-term outcomes.     

Underuse of anticoagulation in patients with atrial fibrillation

Atrial fibrillation (AF) is a major risk factor for ischemic stroke. Guidelines recommend anticoagulation for patients with intermediate and high stroke risk (CHA₂DS₂-VASc score ≥2). Underuse of anticoagulants among eligible patients remains a persistent problem. Evidence demonstrates that the psychology of the fear of causing harm (omission bias) results in physicians’ hesitancy to initiate anticoagulation and an inaccurate estimation of stroke risk. The American Heart Association (AHA) initiated the Get With The Guidelines-AFIB (GWTG-AFIB) module in June 2013 to enhance guideline adherence for treatment and management of AF. Better quality of care for AF patients can be provided by increasing adherence to anticoagulation guidelines and improving patient compliance with anticoagulation therapy through education and established protocols. Nonvitamin K antagonist oral anticoagulants may facilitate better patient adherence due to ease of administration and reduced monitoring burden. In this review, we discuss the reasons for underuse, omission bias contributing to underuse, and different strategies to address this issue.     

非瓣膜性房颤患者的左心耳特征分析

冠状病毒（coronavirus,CoVs）感染主要累及肺部,但对心血管系统损伤作用也不容忽视。CoVs感染引起的心脏损伤并非罕见,其发生与病情的严重程度密切相关。本文首先从CoVs引起心血管损伤的证据入手,进一步探讨了CoVs对心肌的直接损伤,以及肾素血管紧张素（RAS）系统激活和细胞因子风暴与炎症反应对心血管损伤的可能作用机制。相关心血管损伤的可能机制包括,（1）病毒直接作用：CoVs在心肌细胞复制,损伤心肌;（2）RAS系统激活：感染CoVs后,心脏血管紧张素转化酶2（angiotensin-converting enzyme 2,ACE2）的表达下调,激活RAS系统,使得血管紧张素Ⅱ（Angiotensin Ⅱ,Ang Ⅱ）收缩血管功能增强,Ang1-7保护心脏效应减弱;（3）诱发细胞因子风暴：循环细胞因子和全身炎症反应引起心脏损伤;（4）其他：包括低氧血症和儿茶酚胺心脏毒性。本文就相关内容作一综述,为后续的详尽机制和治疗策略研究提供思路。     

Doppler-derived aortic flow measurements during and after heavy isometric exercise in healthy men versus men with myocardial infarction.

Doppler echocardiography is a useful noninvasive determination of left ventricular function during dynamic exercise. Scarce data are available for the use of this technique during heavy isometric exercise. Therefore, Doppler-derived aortic flow indexes were assessed during and after 50% maximal upper-body isometric exercise in 25 healthy men (aged 47 +/- 6 years) and compared with those of 22 men (aged 48 +/- 9 years) who had suffered myocardial infarction. The heart rate increased (p = 0.01) in each of the groups from a mean of 68 +/- 12 at rest to 84 +/- 11 during isometric exercise. At rest, systolic blood pressure was higher (p = 0.05) in the patients with coronary artery disease. During exercise, the patients with cardiac disease, compared with the healthy volunteers, demonstrated a lesser reduction in flow velocity integral, stroke volume, and cardiac indexes (p = 0.001). Immediately on recovery, the patients with cardiac disease, compared with the healthy group, showed significantly greater (p = 0.001) increase in stroke volume and cardiac indexes. At 3 minute's recovery, the stroke volume index continued to increase in the patients with cardiac disease, while the healthy group showed a decrease to below its resting value. Although 50% of maximal upper-body isometric exercise caused similar heart rate and systolic blood pressure responses in healthy patients and patients with cardiac disease, there were significant group differences in Doppler-derived left ventricular systolic function indexes, which were greatest on immediate and 3 minute's recovery. The results suggest that this novel isometric test may be useful in clinical testing.     

高血压并阵发性房颤二尖瓣、肺静脉血流频谱特点的研究

目的对比研究原发性高血压伴有和不伴有阵发性房颤(PAF)患者二尖瓣和肺静脉血流频谱特点.方法年龄、血压和左室心肌重量指数匹配的高血压PAF组24例,非PAF组55例.应用多普勒超声心动图测量二尖瓣舒张早期、舒张晚期血流峰值(E、A)及其流速积分(VTI-E、VTI-A),计算E/A比值;肺静脉血流频谱收缩期、舒张期、血流峰值(PVS、PVD)及其流速积分(VTI-PVS、VTI-PVD)等指标.结果与非PAF组比较,PAF组E和VTI-E显著增加[E:(70.94±18.03) cm/s vs (86.66±26.93) cm/s,P<0.01; TVI-E:(12.93±3.50) cm vs (16.74±4.95) cm,P<0.001];A减低[(89.20±23.44) cm/s vs (78.62±18.96) cm/s,P<0.05),E/A比值增大(0.82±0.24 vs 1.13±0.36,P<0.01);PVD和VTI-PVD增加[PVD:(42.60±12.11) cm/s vs (52.18±14.20) cm/s,P<0.01; TVI-PVD:(10.06±3.19) cm vs (12.16±3.04) cm,P<0.05].结论左房助力泵功能减低、管道功能增强和左房扩大可能是高血压病患者合并PAF的机制之一.     

IL-6、IL-18与心房颤动的关系研究胡耀明

目的：研究心房颤动患者血清IL-6、IL-18水平与心房颤动的关系。方法：入选71个房颤患者进行试验,及年龄与性别相匹配的30名健康志愿者做对照组。酶联免疫吸附法测定血清IL-6、IL-18水平,.超声心动图测定左心房内径。结果： 1. 永久性房颤组血清IL-6、IL-18水平分别高于持续性房颤组, 持续性房颤组水平高于阵发性房颤组,阵发性房颤组水平高于对照组;2房颤患者左心房内径均大于对照组;永久性房颤组大于持续性房颤组;持续性房颤组大于阵发性房颤组。IL-18水平 与LAD成正相关r = 0.26, P < 0.01。IL-6水平与LAD成正相关r = 0.31, P < 0.01。IL-18、与IL-6水平成正相关r = 0.34, P < 0.01。结论：房颤患者IL-6和IL-18水平升高。房颤患者左心房内径增大。细胞因子IL-6和IL-18在AF的发病机制中可能具有重要的作用。     

Prediction of postoperative left ventricular systolic function with Doppler-derived dP/dt in patients with chronic aortic regurgitation.

To evaluate the value of Doppler-derived dP/dt as a predictor of postoperative left ventricular (LV) systolic function in patients with chronic aortic regurgitation, we evaluated 29 patients who underwent aortic valve replacement (n = 17) or valve repair. Doppler-derived dP/dt was determined from the continuous wave Doppler signal of the aortic regurgitation jet preoperatively. Preoperative LV ejection fraction (LVEF) and Doppler-derived dP/dt were 48 +/- 11% and 701 +/- 204 mm Hg/s, respectively. LVEF decreased to 43 +/- 12% at immediate postoperative period and improved to 54 +/- 11% at late postoperative period. In multivariate analysis, only dP/dt was an independent predictor of late postoperative LVEF (r = 0.59, P =.006). A dP/dt 相似文献   

Immunopathogenesis and biomarkers of recurrent atrial fibrillation following ablation therapy in patients with preexisting atrial fibrillation

Introduction: Recurrent atrial fibrillation (RAF) following ablation therapy occurs in about 50% of patients. The pathogenesis of RAF is unknown, but is believed to be driven by atrial remodeling in the setting of background inflammation. Structural, electrophysiological and mechanical remodeling has been associated with atrial fibrillation (AF). Inflammation and fibrotic remodeling are the major factors perpetuating AF, as mediators released from the atrial tissues and cardiomyocytes due to mechanical and surgical injury could initiate the inflammatory process. In this article, we have critically reviewed the key mediators that may serve as potential biomarkers to predict RAF.

Areas covered: Damage associated molecular patterns, heat shock proteins, inflammatory cytokines, non-inflammatory markers, markers of inflammatory cell activity, and markers of collagen deposition and metabolism are evaluated as potential biomarkers with molecular treatment options in RAF.

Expert commentary: Establishing biomarkers to predict RAF could be useful in reducing morbidity and mortality. Investigations into the role of DAMPs participating in a sterile immune response may provide greater insight into the pathogenesis of RAF. Markers evaluating immune cell activity, collagen deposition, and levels of heat shock proteins show the greatest promise as potential biomarkers to predict RAF and develop novel therapies.     

Functional outcome in stroke patients with atrial fibrillation

OBJECTIVES: To identify the prevalence of atrial fibrillation (AF) in a sample of stroke patients and to evaluate the impact of AF on patient clinical characteristics and functional outcome. DESIGN: A retrospective case-comparison study. SETTING: University-affiliated rehabilitation centers. PARTICIPANTS: One hundred ninety-six of 231 consecutive stroke patients admitted to inpatient rehabilitation units were evaluated during the rehabilitation period. MAIN OUTCOME MEASURES: Characteristics of cerebral lesions, patient demographic features, disease duration, length of hospital stay (LOS), risk factors for stroke, and functional status at admission and at discharge were assessed and compared in patients with and without AF. Functional Independence Measure (FIM) and Adapted Patient Evaluation Conference System (APECS) were used to evaluate functional status. RESULTS: AF was diagnosed in 41 (20.1%) patients. Patients who had AF were more likely to have ischemic cerebral lesions. There were no significant differences between the AF and non-AF groups with regard to mean age, LOS, and disease duration. Ischemic and valvular heart disease were more common in patients with AF. Based on FIM and APECS scores, both initial and discharge disability were more severe in patients with AF. In a multivariate model, AF was a negative prognostic factor for functional outcome in stroke patients. CONCLUSION: AF is not only associated with increased risk of stroke, but also with markedly greater disability in stroke patients. Factors such as size and type of cerebral lesions, stroke severity, comorbid conditions, and impact of AF on systemic and cerebral circulation can influence stroke recovery.