Blood-nulled late gadolinium enhancement increases sensitivity for subtle basal myocardial scar in mitral valve prolapse with annular disjunction

Mitral valve prolapse (MVP) with mitral annular disjunction (MAD) is an increasingly recognized arrhythmogenic phenotype in which focal myocardial fibrosis of the basal inferolateral wall serves as a substrate for ventricular arrhythmia and a target for cardiac magnetic resonance (CMR) risk stratification, yet this fibrosis is often subtle and may be obscured on conventional bright-blood late gadolinium enhancement (LGE) imaging where subendocardial scar blends with the adjacent bright blood pool. We describe a 67-year-old woman with known MVP and a 3-mm posterior MAD referred for CMR following 24-hour Holter monitoring that documented frequent premature ventricular contractions, short runs of supraventricular tachycardia, and possible atrial tachycardia with intermittent variable atrioventricular block. Conventional phase-sensitive inversion recovery (PSIR) LGE was interpreted as negative on prospective review, with preserved global left ventricular systolic function and no regional wall motion abnormality. A matched dark-blood PSIR LGE sequence performed at identical slice prescription during the same examination demonstrated a focal mid-to-subendocardial stripe of enhancement in the basal inferolateral wall; with this finding in hand, a faint band of enhancement could be retrospectively identified at the same anatomical location on the conventional images, but had not met the threshold for confident prospective identification. The spatial distribution, in continuity with the disjunctive posterior annulus rather than conforming to a single coronary territory, favored an MVP-MAD-related substrate over an ischemic etiology, and the finding reinforced the indication for continued arrhythmic surveillance and supported electrophysiology consultation. To our knowledge, this is among the first published descriptions of incremental diagnostic yield from dark-blood PSIR LGE in MVP-MAD and supports inclusion of a dark-blood sequence in dedicated MVP-MAD CMR protocols.