Cardiology Division, University Hospitals of Geneva (N.J., D.C.S., P.B.D., M.N.).
Boston Scientific, Rhythm Management, Solothurn, Switzerland (F.J.).
Circ Arrhythm Electrophysiol. 2019 Mar;12(3):e006955. doi: 10.1161/CIRCEP.118.006955.
Background Although entrainment mapping is an established approach to atypical atrial flutter ablation, postpacing intervals shorter than tachycardia cycle length (difference between postpacing interval and tachycardia cycle length [dPPI] <0 ms) remain of unknown significance. We sought to compare anatomic and electrophysiological properties of sites with dPPI <0, dPPI=0-30, and dPPI >30 ms. Methods We studied 24 noncavotricuspid isthmus-dependent macroreentrant atypical atrial flutter in 19 consecutive patients. Ultra high-density electroanatomic activation maps were acquired with a 64-electrode basket catheter. Entrainment mapping was performed at multiple candidate sites. Ablation was performed at the narrowest accessible slow-conducting critical isthmuses. Results Of 102 entrainment mapping sites, dPPI <30 was observed at 72 sites on complete maps of 24 atypical atrial flutter. Compared with dPPI=0-30 sites (N=45), dPPI<0 sites (N=27) were more commonly located within isthmuses <15 mm wide (67% versus 6.7%, P<0.00001; odds ratio, 28.0; 95% CI, 6.8-115.7), more frequently located within 5 mm of the leading wavefront (93% versus 64%, P=0.008), exhibited slower local conduction velocity (0.49±0.43 versus 0.93±0.57 m/s, P=0.0005), lower voltages (0.48±0.79 versus 0.92±0.97 mV, P=0.04), and more frequently fractionated electrograms (67% versus 24%, P=0.0004). High rates of arrhythmia termination or cycle length increase >15 ms by ablation were observed in both dPPI groups (94% versus 86%, P=0.53). Compared with all dPPI <30, dPPI >30 sites (N=30) were less commonly observed within isthmuses (3.3%, P<0.001) or within 5 mm of the leading wavefront (30%, P<0.0001); conduction velocity (1.0±0.7 m/s, P=0.002) and voltage (1.1±1.4 mV, P=0.049) were higher compared with dPPI<0 but similar to dPPI=0-30 sites. Conclusions In atypical atrial flutter, sites with dPPI <0 are markers of limited width critical isthmuses with slower conduction velocity, whereas sites with dPPI=0-30 ms are often not in close proximity to the reentry circuit. Virtual electrode simultaneous down and upstream (antidromic) capture of a confined isthmus of slow conduction can explain a dPPI <0. Identifying these sites may improve selective and efficient ablation strategies compared with the standard 30-ms threshold.
尽管激动标测是一种成熟的非典型房扑消融方法，但起搏后间期短于心动过速周长（起搏后间期与心动过速周长之差 [dPPI] <0 毫秒）仍然意义不明。我们旨在比较 dPPI<0、dPPI=0-30 和 dPPI>30 毫秒的部位的解剖和电生理特性。
我们研究了 19 例连续患者的 24 例非腔静脉三尖瓣峡部依赖性大折返非典型房扑。使用 64 电极篮状导管获取超高密度电激动标测图。在多个候选部位进行激动标测。在可到达的最窄慢传导临界峡部进行消融。
在 24 例非典型房扑的完整图中，102 个激动标测部位中 dPPI<30 的部位为 72 个。与 dPPI=0-30 部位（N=45）相比，dPPI<0 部位（N=27）更常见于<15mm 宽的峡部（67%与 6.7%，P<0.00001；优势比，28.0；95%CI，6.8-115.7），更靠近激动波前 5mm 内（93%与 64%，P=0.008），局部传导速度较慢（0.49±0.43 与 0.93±0.57m/s，P=0.0005），电压较低（0.48±0.79 与 0.92±0.97mV，P=0.04），电激动图更常呈碎裂（67%与 24%，P=0.0004）。两组 dPPI 均观察到消融后心律失常终止或周长增加>15ms 的高发生率（94%与 86%，P=0.53）。与所有 dPPI<30 相比，dPPI>30 部位（N=30）在峡部内的发生率较低（3.3%，P<0.001）或在激动波前 5mm 内的发生率较低（30%，P<0.0001）；传导速度（1.0±0.7m/s，P=0.002）和电压（1.1±1.4mV，P=0.049）高于 dPPI<0，但与 dPPI=0-30 部位相似。
在非典型房扑中，dPPI<0 的部位是狭窄、慢传导临界峡部的标志物，而 dPPI=0-30ms 的部位通常与折返环不接近。局限峡部内的慢传导可解释 dPPI<0 的虚拟电极同时下行和上行（逆行）捕获。与标准 30ms 阈值相比，识别这些部位可能会提高选择性和有效的消融策略。
