Section of Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Heart Rhythm. 2011 Aug;8(8):1169-76. doi: 10.1016/j.hrthm.2011.03.008. Epub 2011 Mar 8.
The substrate for ventricular tachycardia (VT) in nonischemic cardiomyopathy (NICM) has a predilection for the basolateral left ventricle with right bundle branch block VT morphology.
The purpose of this study was to describe a unique group of NICM patients with septal VT substrate.
Between 1999 and 2010, 31 (11.6%) of 266 patients with NICM undergoing VT ablation had septal substrate and no lateral involvement. Mean age was 59 ± 12 years, and ejection fraction was 30% ± 14%. Eight patients had heart block.
Cardiac magnetic resonance showed septal delayed enhancement in 8 of 9 patients. Electroanatomic mapping demonstrated bipolar low voltage (<1.5 mV) extending from the basal septum in 22 of 31 patients. The remaining 9 patients had normal endocardial bipolar voltage but abnormal unipolar septal voltage (<8.3 mV) consistent with intramural abnormalities. Epicardial mapping in 14 patients showed no scar in 9 and patchy basal left ventricular summit scar in 5. VTs were mapped to the septal substrate, with 62% having right bundle branch block morphology and V(2) precordial transition pattern break in 17% suggesting periseptal exit. After substrate and targeted VT ablation, no VT was inducible in 66% and no "clinical targeted" VT in 86%. Over a mean follow-up of 20 ± 28 months, VT recurred in 10 (32%) patients.
Isolated septal VT substrate is uncommon in NICM. Biventricular low-voltage zones extending from the basal septum are characteristic, but septal scarring can be entirely intramural as evidenced by unipolar/bipolar electrograms and imaging. Multiple unmappable morphologies are the rule, often requiring several procedures aggressively targeting the septal substrate to achieve moderate long-term VT control.
非缺血性心肌病（NICM）中室性心动过速（VT）的基质倾向于基底外侧左心室，伴有右束支传导阻滞 VT 形态。
本研究旨在描述一组具有间隔 VT 基质的独特 NICM 患者。
1999 年至 2010 年，266 例 NICM 患者中 31 例（11.6%）接受 VT 消融术，其中有间隔基质而无外侧受累。平均年龄为 59 ± 12 岁，射血分数为 30% ± 14%。8 例患者有心脏传导阻滞。
心脏磁共振显示 9 例中有 8 例存在间隔延迟强化。电解剖图显示 31 例中有 22 例存在从基底间隔延伸的双极低电压（<1.5 mV）。其余 9 例患者的心内膜双极电压正常，但单极间隔电压异常（<8.3 mV），提示存在心室内膜下异常。14 例患者的心脏外膜图显示 9 例无疤痕，5 例左心室顶部有斑片状基底疤痕。VT 被定位到间隔基质，62%有右束支传导阻滞形态，17% V(2)胸前过渡模式中断提示间隔旁出口。在间隔基质和目标 VT 消融后，66%的患者不能诱发 VT，86%的患者没有“临床靶向”VT。平均 20 ± 28 个月的随访中，10 例（32%）患者 VT 复发。
孤立性间隔 VT 基质在 NICM 中并不常见。从基底间隔延伸的双心室低电压区是特征性的，但间隔疤痕可以完全是心室内膜下的，如单极/双极电图和影像学所示。多种不可定位的形态是常见的，通常需要多次手术积极靶向间隔基质，以实现中度的长期 VT 控制。
