Title: Predictors of Paroxysmal Atrial Fibrillation in Patients Undergoing Aortic Valve Replacement
Topic: Arrhythmias
题目：经过AVR病人突发性房颤的预报器
话题：心律失常
Study Question: What are the risk factors for postoperative paroxysmal atrial fibrillation (PAF) after aortic valve replacement (AVR)?
Methods: In this prospective observational study, 300 patients (mean age 62 years) underwent AVR with a mechanical valve. Echocardiograms were performed preoperatively and in the early postoperative period. PAF was detected with frequent electrocardiograms during hospitalization. No patients were treated postoperatively with a beta-blocker or antiarrhythmic drug.
Results: Postoperative PAF occurred in 44% of patients. There were six independent predictors of PAF after AVR, with the strongest predictors being body mass index (BMI) ≤21 kg/m2 (odds ratio [OR], 4.1) and early postoperative ejection fraction (EF) ≤50% (OR, 2.8). The other four risk factors were history of aortic regurgitation, preoperative EF ≤50%, left ventricular end-systolic diameter ≥3.85 cm, and end-systolic septal wall thickness ≥1.75 cm.
Conclusions: Risk factor analysis allows identification of patients who are at highest risk of PAF after AVR, and who are the most appropriate candidates for prophylactic therapies.
Perspective: Multiple prior studies have described the risk factors for PAF after open-heart surgery (most commonly advanced age and prior history of PAF), but very few studies have been limited to patients undergoing only AVR. Regardless of the type of open-heart surgery, postoperative PAF is associated with longer hospitalization and increased morbidity. A low BMI previously has been reported to be a risk factor for poor outcomes after open-heart surgery and myocardial infarction, and the present study demonstrates that low BMI also is predictive of PAF. The explanation for this is unclear, particularly because in the general population, a high BMI (≥30 kg/m2) is an independent predictor of AF. 
研究课题：经过AVR病人术后PAF的风险因素是什么？
方法：在这份前瞻性调查研究的报告中，300名患者经过了AVR，平均年龄为62岁。在病人术后早期已经做了外科手术前的心电图。在患者住院期间，经常用心电图观察PAF。没有任何患者在术后进行beta-blocker或抗心律失常药物治疗。
结果：有44%的病人在手术后出现了PAF.AVR后有6个PAF的预报器，预报器(BMI) ≤21 kg/m2 (odds ratio [OR], 4.1)，早期的术后排泄分数≤50% (OR, 2.8)。另外4个因素是大动脉的回流过程，外科手术前的EF EF ≤50%,左心室末端心脏收缩直径≥3.85 cm，末端心脏收缩隔膜的厚度≥1.75 cm。
结论：风险因素允许病人自己去鉴定尤其是在经过AVR出于高度风险的病人，采用合适的药物进行预防疾病的发生。
观点：大多数先前的研究记录了在病人经过心内直视手术后的出现的PAF风险因素，但是很少的研究局限于病人仅仅经过AVR。不管心内直视手术的类型，术后的PAF要与长期的住院治疗及增加的死亡率联合起来。先前低的BMI对于不好的结果已经成为一个风险因素，在心内直视手术和心肌梗塞后，目前的研究也证明了低BMI是PAF发生的前兆。对于这样的解说不是很清楚，尤其对一般群体而言，BMI(≥30 kg/m2)是AF的一个独立的预示。

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