1.What cardiac surgical procedures are most associated with bradyarrhythmias?
2.What risk factors increase the need for permanent postoperative pacing following cardiac surgery?
3.Is minimally invasive surgery for valve repair associated with a lower incidence of bradyarrhythmias?
4.Is there value in providing temporary pacing following cardiac surgery to prevent bradyarrhythmias?
1 有哪些心脏手术操作与缓慢型心律失常最相关？
2 有哪些危险因素可增加心脏手术后永久起搏几率？
3 微创瓣膜修补术是否可减少的风险？
4 心脏手术后临时起搏是否具有预防缓慢型心律失常的价值？
1 有哪些心脏手术操作与缓慢型心律失常最相关？
心脏手术后经常发生一过性缓慢型心律失常。然而有些程序可能与缓慢型心律失常有高度相关性，检测此种几率的方法之一是观察需要植入永久起搏器的概率。在冠脉搭桥后患者窦房结功能失调或房室传导阻滞需要永久起搏的患者约占0.8-3.4%。然而某些瓣膜手术需要永久起搏器的概率是2-4%，主动脉或三尖瓣手术需要永久起搏的概率升至20-24%。
瓣膜修补术或置换术在导致传导紊乱方面的临床意义是同等的。据报道二尖瓣修补术导致有临床意义的二度或三度房室传导阻滞占患者总数的30.6%，完全传导阻滞的概率是1.5%。
2 有哪些危险因素可增加心脏手术后永久起搏几率？
除手术类型外，以下因素可增加永久起搏的风险：
•二次瓣膜手术
•瓣周钙化
•老年人
•术前左束支阻滞
•左主冠脉狭窄
•动脉搭桥数
•体外循环时间
3 微创瓣膜修补术是否可减少的风险？
据报道右外侧心房切开术或经纵隔上部切口进行微创二尖瓣手术可导致需要永久起搏的的窦房结功能失调。此种手术方法与传统手术方法相比究竟是减少还是增加永久起搏几率目前仍处于观察之中。
4 心脏手术后临时起搏是否具有预防缓慢型心律失常的价值？
尽管没有对临时起搏在预防缓慢型心律失常方面进行研究，但Greenberg等试图确定心房起搏在预防心血管手术后房颤的效能。154名行心脏手术患者在术后72小时内被随机分为非起搏组、右房起搏(RAP)、左房起搏(LAP)、双房起搏(BAP)。所有患者在术后给予β受体阻滞剂。作者发现起搏组房颤发生率(RAP, 8%; LAP, 20%; BAP, 26%)较非起搏组明显减少(37.5%)。术后心房起搏组患者的住院天数减少了22%。从7.8 +/- 3.7 天减至 6.1 +/- 2.3 天 (p = 0.003)。尽管作者得出结论认为术后心房起搏配伍β受体阻滞剂减少房颤发生率和住院天数，但需要评估该效应应用于其他手术的效果（如从冠脉搭桥到主动脉瓣置换等的各种手术）。进一步观察应着重于观察术后（或术中）起搏是否可预防心脏手术后慢型性律失常的几率。
英文参考答案
1 What cardiac surgical procedures are most associated with bradyarrhythmias?
While usually transient, bradyarrhythmias are common following cardiac surgery. Certain procedures, however, have been associated with a higher incidence of these dysrrhythmias, and one measure of their incidence is the need for permanent pacing. Following coronary artery bypass graft surgery, permanent pacing is required for sinus node dysfunction or AV conduction disturbances in 0.8% to 3.4% of patients (1). While some valve operations have an incidence of 2-4% requirement for permanent pacing, aortic or tricuspid valves require permanent pacing in up to 20-24% of their procedures (1).
Of interest, valve repair versus replacement have been associated with almost equal frequencies of clinically important conduction disturbances; mitral valve repairs have been associated with clinically important second or third degree AV blocks in 30.6% of patients, and complete heart block in 1.5% of patients (2).
2 What risk factors increase the need for permanent postoperative pacing following cardiac surgery?
In addition to the type of surgery (as noted above), several factors can increase the risk for permanent pacing; they include (3):
•repeat valve surgery
•perivalvular calcification
•older age
•preoperative left bundle branch block
•left ventricular aneurysmectomy
•left main coronary artery stenosis
•number of bypassed arteries
•cardiopulmonary bypass time
3 Is minimally invasive surgery for valve repair associated with a lower incidence of bradyarrhythmias?
The right lateral atriotomy or the transseptal superior approach utilized for minimally invasive mitral valve operations has been noted to cause sinus node dysfunction requiring permanent pacing. Whether the incidence will ultimately prove to be less or more than traditional open heart approaches is the subject of current investigations (2).
4 Is there value in providing temporary pacing following cardiac surgery to prevent bradyarrhythmias?
Although the value of temporary pacing in preventing bradyarrhythmias has not been studied, Greenberg et al.(3) attempted to determine the efficacy of atrial pacing in the prevention of atrial fibrillation following cardiovascular surgery. A total of 154 patients undergoing cardiac surgery were randomized to either no pacing, right atrial (RAP), left atrial (LAP) or biatrial pacing (BAP) for 72 h after surgery. Beta-adrenergic blocking agents were administered concurrently to all patients following surgery. The authors noted that the incidence of atrial fibrillation was lower in each of the paced groups (RAP, 8%; LAP, 20%; BAP, 26%) compared with patients who did not receive postoperative pacing (37.5%), and that the length of hospital stay was reduced by 22% from 7.8 +/- 3.7 days to 6.1 +/- 2.3 days (p = 0.003) in patients assigned to postoperative atrial pacing. Although the authors concluded that postoperative atrial pacing, in conjunction with beta-blockade, significantly reduced both the incidence of atrial fibrillation and the length of hospital stay following cardiovascular surgery, additional investigation will be needed to evaluate the effects on specific types of surgical interventions (the study population had a variety of surgical interventions from CABG to aortic valve replacements). Additional investigations may shed light on whether postoperative (or intraoperative) pacing would also prevent the incidence of bradyarrhythmias following cardiac surgery.
References:
1.Jaeger FJ, Trohman RG, Brener S, Loop F. Permanent pacing following repeat cardiac valve surgery. Am J Cardiol 1994;74(5):505-7.
2.Brodell GK, Cosgrove D, Schiavone W, Underwood DA, Loop FD. Cardiac rhythm and conduction disturbances in patients undergoing mitral valve surgery. Cleve Clin J Med. 1991;58(5):397-9.
3.Chung MK. Cardiac surgery: postoperative arrhythmias. Crit Care Med 2000;28 (Suppl) N136-44.
4.Greenberg MD, Katz NM, Iuliano S, Tempesta BJ, Solomon AJ. Atrial pacing for the prevention of atrial fibrillation after cardiovascular surgery. J Am Coll Cardiol. 2000;35:1416-22.
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