Localized Intramural Reentry Confined Within the Ventricular Septum in Lamin Cardiomyopathy.

Key Teaching Points•LMNA mutations are characterized by septal and basal anterior wall substrate, which can be detected by microcatheters placed within the distal tributaries of the coronary venous system.•Intramural recordings enhance the ability to characterize both the arrhythmogenic substrate and ventricular tachycardia circuit in cases where diastolic components are absent from surface recordings.•Localized reentry can occur completely confined inside in the septum. •LMNA mutations are characterized by septal and basal anterior wall substrate, which can be detected by microcatheters placed within the distal tributaries of the coronary venous system.•Intramural recordings enhance the ability to characterize both the arrhythmogenic substrate and ventricular tachycardia circuit in cases where diastolic components are absent from surface recordings.•Localized reentry can occur completely confined inside in the septum.