Department of Internal Medicine, Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Pusan National University, School of Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
Pacing Clin Electrophysiol. 2024 Feb;47(2):300-311. doi: 10.1111/pace.14905. Epub 2023 Dec 27.
The anatomic extent of the reentry circuit in idiopathic left posterior fascicular ventricular tachycardia (LPF-VT) is yet to be fully elucidated. We hypothesized that entrainment mapping could be used to delineate the reentry circuit of an LPF-VT, especially including the upper turnaround point.
Twenty-three consecutive LPF-VT patients (mean age, 29 ± 9 years, 18 males) were included. We performed overdrive pacing with entrainment attempts at the left bundle branch (LBB) and the left His bundle (HB) region.
Overdrive pacing from the LBB region showed concealed fusion in all 23 patients (post-pacing interval [PPI], 322.1 ± 64.3 ms; tachycardia cycle length [TCL], 319.0 ± 61.6 ms; PPI-TCL, 3.1 ± 4.6 ms) with a long stimulus-to-QRS interval (287.9 ± 58.0 ms, approximately 90% of the TCL). Pacing from the same LBB region at a slightly faster pacing rate showed manifest fusion with antidromic conduction to the LBB and minimal in-and-out time to the LBB potential (PPI-TCL, 21.3 ± 13.7 ms). Overdrive pacing from the left HB region showed manifest fusion with a long PPI-TCL (53.9 ± 22.5 ms).
Our pacing study results suggest that the upper turnaround point in a reentry circuit of the LPF-VT may extend to the proximal His-Purkinje conduction system near the LBB region but below the left HB region. The LPF may constitute the retrograde limb of the reentry circuit.
特发性左后间隔部室性心动过速（LPF-VT）折返环的解剖范围尚未完全阐明。我们假设激动标测可以用于描绘 LPF-VT 的折返环，特别是包括上部折返点。
连续纳入 23 例 LPF-VT 患者（平均年龄 29±9 岁，18 例男性）。我们在左束支（LBB）和左希氏束（HB）区域进行超速起搏并尝试激动标测。
在所有 23 例患者中，从 LBB 区域进行超速起搏均显示隐匿性融合（起搏后间期[PPI]，322.1±64.3ms；心动过速周长[TCL]，319.0±61.6ms；PPI-TCL，3.1±4.6ms），刺激-QRS 间期较长（287.9±58.0ms，约为 TCL 的 90%）。在稍快的起搏频率下，从同一 LBB 区域起搏可显示显性融合，逆行激动至 LBB，且 LBB 电位的内向和外向时间最小（PPI-TCL，21.3±13.7ms）。从左 HB 区域进行超速起搏显示显性融合，PPI-TCL 较长（53.9±22.5ms）。
我们的起搏研究结果表明，LPF-VT 折返环的上部折返点可能延伸至 LBB 区域附近的近端希氏-浦肯野传导系统，但低于左 HB 区域。LPF 可能构成折返环的逆行支。
