Srinivasan Neil T, Garcia Jason, Schilling Richard J, Ahsan Syed, Hunter Ross J, Lowe Martin, Chow Anthony W, Lambiase Pier D
Department of Cardiac Electrophysiology, The Essex Cardiothoracic Centre, Basildon, Essex, United Kingdom.
Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom.
Heart Rhythm O2. 2021 May 11;2(3):280-289. doi: 10.1016/j.hroo.2021.05.003. eCollection 2021 Jun.
The presence of dynamic substrate changes may facilitate functional block and reentry in ventricular tachycardia (VT).
We aimed to study dynamic ventricular repolarization changes in critical regions of the VT circuit during sensed single extrastimulus pacing known as the Sense Protocol (SP).
Twenty patients (aged 67 ± 9 years, 17 male) underwent VT ablation. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular SP pacing at 20 ms above ventricular effective refractory period. Ventricular repolarization maps were constructed. Ventricular repolarization time (RT) was calculated from unipolar electrogram T waves, using the Wyatt method, as the dV/dt of the unipolar T wave. Entrainment or pace mapping confirmed critical sites for ablation.
The median global repolarization range (max-min RT per patient) was 166 ms (interquartile range [IQR] 143-181 ms) during SR mapping vs 208 ms (IQR 182-234) during SP mapping ( = .0003 vs intrinsic rhythm). Regions of late potentials (LP) had a longer RT during SP mapping compared to regions without LP (mean 394 ± 40 ms vs 342 ± 25 ms, < .001). In paired regions of normal myocardium there was no significant spatial dispersion of repolarization (SDR)/10 mm during SP mapping vs SR mapping (SDR 11 ± 6 ms vs 10 ± 6 ms, = .54). SDR/10 mm was greater in critical areas of the VT circuit during SP mapping 63 ± 29 ms vs SR mapping 16 ± 9 ms ( < .001).
Ventricular repolarization is prolonged in regions of LP and increases dynamically, resulting in dynamic SDR in critical areas of the VT circuit. These dynamic substrate changes may be an important factor that facilitates VT circuits.
动态底物变化的存在可能会促进室性心动过速（VT）中的功能性阻滞和折返。
我们旨在研究在称为感知方案（SP）的感知单个额外刺激起搏期间，VT 环路关键区域的动态心室复极化变化。
20 名患者（年龄 67±9 岁，17 名男性）接受了 VT 消融。在窦性心律（SR）期间以及在高于心室有效不应期 20 毫秒的右心室 SP 起搏期间获得双极电压图。构建心室复极化图。使用 Wyatt 方法从未ipolar 电图 T 波计算心室复极化时间（RT），作为 unipolar T 波的 dV/dt。拖带或起搏标测确定消融的关键部位。
在 SR 标测期间，整体复极化范围中位数（每位患者的最大 - 最小 RT）为 166 毫秒（四分位数间距[IQR]143 - 181 毫秒），而在 SP 标测期间为 208 毫秒（IQR 182 - 234）（与固有节律相比，P =.0003）。与无晚期电位（LP）的区域相比，LP 区域在 SP 标测期间的 RT 更长（平均 394±40 毫秒对 342±25 毫秒，P <.001）。在正常心肌的配对区域中，SP 标测与 SR 标测期间复极化的空间离散度（SDR）/10 毫米无显著差异（SDR 11±6 毫秒对 10±6 毫秒，P =.54）。在 SP 标测期间，VT 环路关键区域的 SDR/10 毫米大于 SR 标测期间（63±29 毫秒对 16±9 毫秒，P <.001）。
LP 区域的心室复极化延长且动态增加，导致 VT 环路关键区域出现动态 SDR。这些动态底物变化可能是促进 VT 环路的一个重要因素。
