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Double-QRS Complex Revealing a Multilayer Intramural-Epicardial Ventricular Tachycardia Circuit in Cardiac
Masao Takahashi1, Yoshiaki Mizunuma1, Takafumi Sasaki1
1Department of Cardiology, Tokyo Metropolitan Hiroo Hospital, Tokyo, Japan.
Background:
Cardiac sarcoidosis can create multilayer intramural-epicardial conduction pathways that manifest as subtle electrocardiographic abnormalities during sinus rhythm. A second low-amplitude deflection following the QRS complex ("double-QRS") has been observed clinically, but its electrophysiological mechanism remains unclear.
Case Summary:
A 67-year-old man with cardiac sarcoidosis exhibited a sinus-rhythm double-QRS pattern that changed in timing and polarity after corticosteroid therapy and preceded sustained monomorphic ventricular tachycardia. High-density mapping identified 2 intramural-epicardial connections linking a broad intramural septal corridor to epicardial breakthrough sites at the anterior right ventricular outflow tract and inferior right ventricle. Entrainment confirmed a multilayer reentry circuit. Ablation targeting the intramural isthmus and epicardial exits modified the double-QRS timing, and definitive bipolar ablation eliminated all inducible ventricular tachycardia and abolished the double-QRS pattern.
Discussion:
A sinus-rhythm double-QRS complex may reflect delayed epicardial activation through intramural-epicardial pathways.
Take-Home Message:
Resolution of a double-QRS complex after ablation supports its role as a surface electrocardiographic marker of multilayer conduction.
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