Homophasic idiopathic intermittent left bundle branch block and cardiac memory (OIL-CAME): reappraisal of a distinct electrocardiographic phenotype

Aim: Cardiac memory is classically expressed as persistent T wave changes following restoration of normal ventricular activation. Its manifestations in idiopathic intermittent left bundle branch block (ILBBB) remain incompletely characterized. The aim of this report is to describe a distinct electrocardiographic phenotype potentially related to cardiac memory. Methods: We retrospectively analyzed a homogeneous series of 14 patients with idiopathic, rate-dependent ILBBB, absence of demonstrable structural heart disease, homophasic T waves in leads V5–V6 during left bundle branch block (LBBB), and pseudo-ischemic T wave inversion in the right precordial leads during phases of normal conduction. Results: In all patients, memory-related negative T waves were observed during normal conduction, while concordant (homophasic) T waves were consistently present during LBBB. A close relationship emerged between the width of the intraventricular conduction zone and the severity of repolarization abnormalities: narrower conduction zones were associated with deeper T wave inversion during normal conduction. During follow-up, most patients progressed to permanent LBBB, without documented major arrhythmic events. Conclusions: These findings describe a distinctive and reproducible electrocardiographic phenotype within idiopathic ILBBB, likely related to cardiac memory. This pattern, provisionally designated homophasic idiopathic intermittent left bundle branch block and cardiac memory (OIL-CAME), warrants further confirmation in larger prospective studies.