Catheter Ablation of the Mitral Isthmus for Ventricular Tachycardia Associated with Inferior Infarction
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- 作者：David Wilber ; John Kall ; Douglas Kopp ; Dennis Glascock ; Charles Kinder
- 刊名：Journal of the American College of Cardiology
- 出版年：1995
- 出版时间：February 1995
- 年：1995
- 卷：25
- 期：2, Supplement 1
- 页码：41A
- 全文大小：117 K
文摘
Catheter ablation (CA) of ischemic sustained monomorphic ventricular tachycardia (SMVT) remains problematic due to the presence of multiple potential functional circuits. We identified 3 pts with SMVT and a posterior akinetic/dyskinetic segment in whom anatomic constraints on the reentrant circuit facilitated CA. Each pt had 2-40 episodes of spontaneous SMVT in the previous month despite amiodarone. SMVT had either a LBBB (rS in V1, R in V6) right superior axis morphology (M), or a RBBB (R in V1, QS in V6) left superior axis M. Both M were reproducibly induced in each pt (cycle length [CL] 600-320 ms). In each pt, both M appeared to share a similar slow conduction zone in the inferobasal left ventricle adjacent to the mitral valve annulus. During SMVT of either M, these sites were characterized by diastolic potentials with electrogram-QRS intervals of 115-251 ms (24-58 % of SMVT CL) and concealed entrainment during pacing associated with stimulus-QRS intervals of 105-411 ms (23-92 % of SMVT CL). Application of radiofrequency energy (50 W for 90-120 s) at one of these sites in each pt (figure) resulted in termination of SMVT within 2-12 complexes. Following CA, neither M could be induced in any pt. In 1 pt, SMVT with a third nonclinical QRS M (CL 250 ms) remained inducible. All pts had implantable defibrillators with RR interval and/or electrogram storage. During 1-5 mo follow-up, no pt has had spontaneous SMVT or shocks. Conclusions: An isthmus of surviving myocardium adjacent to the mitral valve annulus may constitute a critical region of slow conduction in some pts with inferior MI and recurrent SMVT, providing a vulnerable and anatomically localized target for CA. Characteristic SMVT morphologies may identify candidates for this approach.