Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Heart Rhythm. 2010 Mar;7(3):305-11. doi: 10.1016/j.hrthm.2009.11.006. Epub 2009 Nov 10.
Re-entry is the most common mechanism of sustained monomorphic ventricular tachycardia (VT) in patients with coronary artery disease and prior myocardial infarction (MI).
This study sought to report the electrophysiological properties of a series of patients with prior MI who underwent radiofrequency ablation (RFA) for VT originating instead from a focal source.
The electrophysiological properties of 46 patients with prior MI (male 89%, age 64.8 +/- 10.2 years) who underwent RFA for sustained VT were studied. A total of 101 VTs were induced (92 [91%] macro-re-entrant VT and 9 [9%] focal VT).
One patient had adenosine-sensitive idiopathic focal VT. The focal VT group had a significantly shorter pre-systolic interval (electrogram to QRS) during VT compared with the macro-re-entrant VT group (36 +/- 17 ms vs. 117 +/- 67 ms, P = .001). The successful ablation sites in the focal VT group also had a significantly lower ratio (in percentage) of electrogram-QRS interval to diastolic interval (VT cycle length - QRS duration) during VT (14 +/- 8%) as compared with macro-re-entrant VTs (48 +/- 30%, P <.001). Focal VTs demonstrated an apparent point source of endocardial activation and could not be entrained, whereas 77% of macro-re-entrant VTs were entrained. Successful ablation sites for focal VT (success rate 100%) were predominantly in the basal half of the left ventricle (75%), whereas only 60% of macro-re-entrant VTs (success rate 90.7%) were basal (P = .01). However, the procedure time, VT cycle length, number of RFA applications required for success, and acute success results were not significantly different in these 2 groups.
A focal mechanism is present in up to 9% of VTs in patients with CAD and prior MI that are induced during electrophysiology study for RF ablation. Mechanistic distinction from more typical macro-re-entrant VT in this population is important because ablation site characteristics are very different.
再进入是冠心病和心肌梗死（MI）患者持续性单形性室性心动过速（VT）的最常见机制。
本研究旨在报告一组接受射频消融（RFA）治疗起源于局灶性源的 VT 的 MI 后患者的电生理特性。
研究了 46 例 MI（男性 89%，年龄 64.8+/-10.2 岁）后接受 RFA 治疗持续性 VT 的患者的电生理特性。共诱发 101 次 VT（92[91%]大折返性 VT 和 9[9%]局灶性 VT）。
1 例腺苷敏感特发性局灶性 VT。局灶性 VT 组 VT 时的预收缩间期（心电图至 QRS）明显短于大折返性 VT 组（36+/-17 ms 比 117+/-67 ms，P=0.001）。局灶性 VT 组成功消融部位在 VT 时的心电图-QRS 间期与舒张间期（VT 周期长度-QRS 持续时间）的比值（%）也明显低于大折返性 VT（14+/-8%比 48+/-30%，P<0.001）。局灶性 VT 表现出明显的心内膜激活点源，不能夺获，而 77%的大折返性 VT 可夺获。局灶性 VT 的成功消融部位（成功率 100%）主要位于左心室基底半部（75%），而大折返性 VT 的成功部位（成功率 90.7%）仅为基底（P=0.01）。然而，两组的程序时间、VT 周期长度、成功所需的 RFA 应用次数和急性成功结果均无显著差异。
在接受射频消融治疗的 CAD 和 MI 后患者中，VT 的发生率高达 9%，这是电生理研究中诱导的。在这一人群中，与更典型的大折返性 VT 进行机制区分很重要，因为消融部位的特征非常不同。
