Nitta T, Schuessler R B, Mitsuno M, Rokkas C K, Isobe F, Cronin C S, Cox J L, Boineau J P
Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA.
Circulation. 1998 Mar 31;97(12):1164-75. doi: 10.1161/01.cir.97.12.1164.
The central common pathway, which is the target for ablation in reentrant ventricular tachycardia, can be localized by entrainment mapping techniques. However, localization of the pathway is not always possible because of the elevated pacing threshold and the low voltage and fractionated potentials at the pathway. We examined whether return cycle mapping after entrainment localizes the pathway without pacing at the pathway or recording the potentials from the pathway and determined the required electrode resolution to localize the pathway.
Epicardial mapping was performed with 253 unipolar electrodes during and after entrainment of 13 morphologies of ventricular tachycardia that were induced in dogs 4 days after infarction. The return cycle was calculated by subtracting the first activation time from the second activation time after the last stimulus and the return cycle distribution map was constructed for each stimulation site. The return cycle isochrones equal to the ventricular tachycardia cycle length converged on the lines of conduction block irrespective of the stimulation site, and the central common pathway was localized at the region between the intersections of the return cycle isochrones after entrainment from different stimulation sites. The potentials from the central common pathway were not required to localize the pathway, and the mapping accuracy did not change with or without analysis of the potentials from the pathway. According to the correlation between the electrode resolution and the mapping accuracy, an interelectrode distance of 8.5 mm was estimated as sufficient resolution for successful tachycardia termination during radiofrequency ablation guided by return cycle mapping.
Return cycle mapping after entrainment localizes the central common pathway without pacing at the pathway or recording the potentials from the pathway. This new mapping technique could improve the success rate of the ablative procedures.
折返性室性心动过速的消融靶点是中央共同通路，可通过拖带标测技术进行定位。然而，由于起搏阈值升高以及该通路上电压低和电位碎裂，通路的定位并非总是可行。我们研究了拖带后的回归周期标测是否能在不通路起搏或记录通路上电位的情况下定位通路，并确定了定位通路所需的电极分辨率。
在梗死4天后的犬身上诱发13种形态的室性心动过速，在拖带期间及之后用253个单极电极进行心外膜标测。回归周期通过用最后一次刺激后的第二次激动时间减去第一次激动时间来计算，并为每个刺激部位构建回归周期分布图。与室性心动过速周期长度相等的回归周期等时线汇聚在传导阻滞线上，而不论刺激部位如何，中央共同通路位于从不同刺激部位拖带后回归周期等时线交点之间的区域。定位通路不需要中央共同通路上的电位，且无论是否分析通路上的电位，标测准确性均无变化。根据电极分辨率与标测准确性之间的相关性，估计电极间距为8.5 mm作为回归周期标测引导下射频消融期间成功终止心动过速的足够分辨率。
拖带后的回归周期标测可在不通路起搏或记录通路上电位的情况下定位中央共同通路。这种新的标测技术可提高消融手术的成功率。
