Kreiner G, Heinz G, Siostrzonek P, Gössinger H D
Department of Cardiology, University of Vienna, Austria.
Circulation. 1996 Jan 15;93(2):277-83. doi: 10.1161/01.cir.93.2.277.
Catheter ablation of the posteroseptal right atrium has been proposed for control of ventricular rate in patients with tachycardic atrial fibrillation (AF). However, the exact mechanism of rate control is unclear. Because the ablation site corresponds to the location of the slow pathway in patients with AV nodal reentry tachycardia (AVNRT), we investigated whether selective ablation of this posterior AV nodal input can provide a sufficient reduction in heart rate during AF.
In 30 patients with AVNRT, conduction properties of the AV nodal pathways were determined before and after slow pathway ablation. AF was induced by burst pacing at baseline and after ablation, and the mean ventricular cycle length was determined. After slow pathway ablation, the mean ventricular cycle length during AF increased (449 +/- 98 versus 515 +/- 129 milliseconds, P < .01). At baseline, the mean ventricular cycle length correlated with the Wenckebach cycle length of both the slow (r = .90) and fast (r = .86) pathways. After ablation, the mean ventricular cycle length was extremely well determined by the Wenckebach cycle length of the fast pathway (r = .94). However, the slope of the regression line was significantly steeper compared with baseline (1.50 versus 0.77, P < .0001), illustrating that the reduction in ventricular rate was not as evident if the fast pathway had a short Wenckebach cycle length.
Selective elimination of the slow pathway reduces ventricular rate during AF. However, in patients with a short Wenckebach cycle length of the anterior AV nodal input that causes tachycardic AF, this effect may be insufficient to provide adequate control of ventricular rate.
已提出对右心房后间隔进行导管消融以控制快速性心房颤动（AF）患者的心室率。然而，心率控制的确切机制尚不清楚。由于消融部位对应于房室结折返性心动过速（AVNRT）患者的慢径路位置，我们研究了选择性消融该后向房室结输入是否能在房颤期间充分降低心率。
对30例AVNRT患者在慢径路消融前后测定房室结径路的传导特性。在基线和消融后通过短阵猝发起搏诱发房颤，并测定平均心室周期长度。慢径路消融后，房颤期间的平均心室周期长度增加（449±98与515±129毫秒，P<.01）。在基线时，平均心室周期长度与慢径路（r=.90）和快径路（r=.86）的文氏周期长度相关。消融后，平均心室周期长度由快径路的文氏周期长度很好地确定（r=.94）。然而，与基线相比，回归线的斜率明显更陡（1.50对0.77，P<.0001），说明如果快径路的文氏周期长度较短，心室率的降低就不那么明显。
选择性消除慢径路可降低房颤期间的心室率。然而，对于因快速性房颤导致前向房室结输入文氏周期长度较短的患者，这种效果可能不足以充分控制心室率。
