Abstract
A coved-type electrocardiogram (ECG) change in Brugada syndrome is suggested to be the result of abnormally delayed depolarization over the right ventricular outflow tract; however, ischemia of the conus branch of the right coronary artery presents the same ECG change. A 63-year-old man with a history of myocardial infarction demonstrated a transient coved-type ECG change during catheter ablation of ventricular tachycardia. The ECG change appeared during left ventricular mapping without any chest symptoms, and recovered spontaneously. A pilsicainide test was negative and a coved-type ECG did not appear during the perioperative or follow-up period.
Keywords: Ventricular tachycardia, Brugada-type electrocardiogram
1. Introduction
A coved-type elevation is a typical electrocardiogram (ECG) change associated with Brugada syndrome (BrS). In a recent study, Nademanee et al. demonstrated that the underlying electrophysiological mechanism of BrS is abnormally delayed depolarization over the anterior aspect of the right ventricular outflow tract epicardium [1]. The association between BrS and vasospasms has been reported in several cases, and a coved-type ST elevation is known to be a result of ischemia of the conus branch of the right coronary artery [2]. Here we present a rare case of coved-type ECG change in a patient with ischemic heart disease during an ischemic ventricular tachycardia (VT) ablation procedure.
2. Case report
A 63-year-old man demonstrated a transient coved-type ECG change during catheter ablation of ischemic VT (Fig. 1). The patient had a history of both anteroseptal and inferior myocardial infarctions following coronary artery bypass grafting: left internal thoracic artery–#7, right internal thoracic artery–#10, and gastroepiploic artery–#4 posterior descending branch. Echocardiography revealed hypokinesis of the left ventricle (LV) both in the anterior and inferior walls with a partial anterior aneurysm. The baseline ECG showed slight ST-elevation in the chest leads (Fig. 1), which may have been caused by an anterior aneurysm.
Fig. 1.
Twelve-lead electrocardiogram at baseline and coved-type ST elevation during left ventricle mapping.
ECG changes emerged when creating a substrate map of the LV (Fig. 2A), near the inferior mitral valve. A long transseptal sheath was introduced into the LV under intracardiac echocardiography guidance without causing an air-embolism. While performing the LV substrate mapping, the long transseptal sheath and mapping catheter appeared to have pushed against the LV wall (Fig. 2A) and premature ventricular contractions were frequently observed. During the ECG change, there were no chest symptoms and his blood pressure and heart rate remained stable. It took approximately 20 s for the ECG change to appear and it lasted for approximately 2 min; the change recovered spontaneously during observation.
Fig. 2.
(A) Anteroposterior view when the catheter bumped the left ventricle wall. (B) A low voltage area in the anterior wall of the left ventricle. (C) A low voltage area in the inferior wall of the left ventricle.
A voltage map revealed a dense scar in both the anterior and inferior regions (Fig. 2B and C), and an irrigated radiofrequency application to the inferior scar region with good pace mapping rendered the targeted VT noninducible. A pilsicainide test was negative and no coved-type ECGs have appeared since then.
3. Discussion
To the best of our knowledge, a Brugada-like ECG induced by catheter manipulation during ischemic VT ablation has not been previously reported. There are many reports of ST elevation in the inferior leads during ablation after the Brockenbrough technique [3]; however, this patient exhibited an ECG change mainly in leads V1 and V2 without any reciprocal changes within 5 min of the Brockenbrough approach. The mechanism of the ECG change was unknown. The conus branch of the right coronary artery is well known to supply the right ventricular outflow tract. Air embolisms and vasospasms during ablation have been reported in several cases [3]. In this case, ischemia of the conus branch of the right coronary artery was considerable; however, the absence of chest symptoms and immediate recovery of ST elevation indicates that involvement of the coved-type ECG change and ischemia was impossible to verify. There are reported cases of VT/ventricular fibrillation, induced during coved-type ST-elevation by ischemia of the conus branch of the right coronary artery [4]. However, in our case, VT was sustained neither during the ST-elevation nor by electrical stimulation after the procedure; thus the clinical significance of coved-type ECG change during catheter ablation of ischemic VT was unclear.
Conflict of interest
The authors have no conflicts of interest to declare.
Disclosures and funding sources
None.
References
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