Transcoronary mapping using a guidewire during transcoronary ethanol ablation for ventricular tachycardia with a deep intramural substrate: a case report

Abstract

Background: Transcoronary ethanol ablation is effective in treating ventricular tachycardia (VT) in the deep myocardium. The selection of the target coronary artery plays an important role in the success of transcoronary ethanol ablation. Transcoronary mapping, using a guidewire, may be effective for identifying the target coronary artery.

Case summary: A 72-year-old man, who had undergone thrombolytic therapy for acute myocardial infarction 40 years ago, was admitted to the emergency department with a chief complaint of syncope. Five years ago, a cardiac resynchronization therapy defibrillator was implanted for a left bundle branch block (QRS duration 153 ms), with New York Heart Association Class Ⅲ and a left ventricular ejection fraction of 30%.Due to VT, he experienced a critical deterioration in his vital parameters, leading to shock. The first VT ablation was performed on the 3rd day of hospitalization. Activation mapping showed that the earliest activation site was located in the mid-anterior septum of the left ventricle. Mapping from the endocardial surface showed no mid-diastolic potential around the VT. Radiofrequency catheter ablation therapy was performed at the targeted site, resulting in transient termination of VT. However, the VT showed recurrence the next day. A transcoronary ethanol ablation was performed on the 10th day of hospitalization. A 0.014 inch guidewire and microcatheter were advanced into the target coronary septal branch, and the myocardial septum was mapped. The guidewire-assisted transcoronary mapping showed a potential 43 ms ahead of QRS onset during VT. The coronary septal artery branch was considered the target artery, and 0.5 mL of ethanol was injected. No further VT was observed for 12 months after the transcoronary ethanol ablation.

Discussion: Transcoronary ethanol ablation is considered in cases where a deep intramural substrate is suspected or when early activation at the interventricular septum is identified. Guidewire-assisted transcoronary mapping allows mapping of VT with deep intramural substrates and may be useful in selecting target coronary arteries while performing transcoronary ethanol ablation.

Keywords: Case report; Transcoronary ethanol ablation; Transcoronary mapping; Ventricular tachycardia.

Figure 1

Target ventricular tachycardia.

Figure 2

(A) Activation mapping shows that the earliest activation site was located at the mid-anterior septum of the left ventricle. Entrainment pacing was performed from this site. (B and C) Show concealed fusion, and the post-pacing interval was consistent with the ventricular tachycardia cycle length.

Figure 3

(A, B, and C) Coronary angiography reveals that three septal branches are from the distal part of the left anterior descending artery. A 0.014 inch guidewire and a microcatheter are advanced into the target coronary septal branch. (D) Transcoronary mapping using the guidewire shows a potential 43 ms ahead of QRS onset during ventricular tachycardia and ventricular tachycardia exit shown by the ablation catheter on the endocardial surface, and furthermore, the potential is fragmented.