Tada H, Nogami A, Naito S, Horie Y, Suguta M, Nakatsugawa M, Hoshizaki H, Oshima S, Taniguchi K
Cardiology Division, Gunma Prefectural Cardiovascular Center, Maebashi, Japan.
Jpn Circ J. 1999 Apr;63(4):244-8. doi: 10.1253/jcj.63.244.
Changes in P-wave morphology in inferior leads during atrial pacing at the margins of the carvo-tricuspid isthmus have been reported to be useful for predicting the creation of isthmus block in radiofrequency (RF) ablation of type I atrial flutter (AFL). However, it is not known whether these changes in P-wave morphology allow the clinician to differentiate between complete isthmus block and slow isthmus conduction. P-wave morphology during low lateral right atrial (LLRA) pacing, as well as during coronary sinus ostium (PCS) pacing, was evaluated prior to ablation, during slow isthmus conduction, and after complete isthmus block in 30 patients with AFL. Changes in P-wave morphology during LLRA pacing were not sufficient to differentiate between complete isthmus block and slow isthmus conduction. While changes in P-wave morphology in lead II from inverted to biphasic during PCS pacing were observed in both slow isthmus conduction and complete isthmus block, the ratio of the positive component to the total P-wave amplitude (P-wave ratio) was significantly different between slow isthmus conduction (20+/-17%) and complete isthmus block (40+/-11%) (P<0.0001). When the P-wave ratio in lead II during PCS pacing was more than 75% of the F-wave ratio in lead II during AFL, bilateral complete isthmus block was predicted with a sensitivity of 88%, a specificity of 71%, a positive predictive value of 75%, and a negative predictive value of 85%. These results indicate that a P-wave ratio greater than 20% or a P-wave ratio during PCS pacing greater than 75% of the F-wave ratio during AFL may predict a bidirectional complete isthmus block.
据报道，在三尖瓣峡部边缘进行心房起搏时，下壁导联P波形态的变化有助于预测I型心房扑动（AFL）射频（RF）消融术中峡部阻滞的形成。然而，尚不清楚这些P波形态的变化能否使临床医生区分完全峡部阻滞和峡部缓慢传导。在30例AFL患者中，于消融术前、峡部缓慢传导期间及完全峡部阻滞术后，评估了低位右房（LLRA）起搏以及冠状窦口（PCS）起搏时的P波形态。LLRA起搏时P波形态的变化不足以区分完全峡部阻滞和峡部缓慢传导。虽然在峡部缓慢传导和完全峡部阻滞时均观察到PCS起搏期间II导联P波形态从倒置变为双相，但峡部缓慢传导（20±17%）和完全峡部阻滞（40±11%）时正向成分与总P波振幅的比值（P波比值）有显著差异（P<0.0001）。当PCS起搏期间II导联的P波比值超过AFL期间II导联F波比值的75%时，预测双侧完全峡部阻滞的敏感性为88%，特异性为71%，阳性预测值为75%，阴性预测值为85%。这些结果表明，P波比值大于20%或PCS起搏期间的P波比值大于AFL期间F波比值的75%可能预测双向完全峡部阻滞。
