Dark papillary muscles sign: a novel prognostic marker for cardiac magnetic resonance

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background the prognostic role of left ventricular (LV) papillary muscle abnormalities in patients with preserved LV systolic ejection fraction (LVEF) is unknown. Aim to evaluate the prevalence and the clinical and prognostic impact of papillary muscle abnormalities by CMR in patients with ventricular arrhythmias, preserved LVEF with no cardiac disease. Methods 391 patients with >500/24h premature ventricular complexes and/or with non-sustained ventricular tachycardia (NSVT), preserved LVEF and no cardiac disease, were enrolled. Different features of LV papillary muscles were considered: supernumerary muscles, papillary thickness, the attachment, late gadolinium enhancement (LGE). The end-systolic hypointensity was defined when its measured signal intensity (SI) was lower than the SI of the septum in early post-contrast cine CMR images. Dark-Paps was defined when both the main papillary muscles had systolic hypointensity. Mitral valve prolapse, mitral annular disjunction (MAD), myocardial LGE were considered. The outcome of hard cardiac events was define as a composite of cardiac death, resuscitated cardiac arrest, and appropriate implantable cardioverter defibrillator (ICD) shock, sustained ventricular tachycardia (lasting ≥30 s at ≥100 beats/min). Results Dark-Paps was found in 79 (20%) patients and was more frequent in females. It was associated with higher prevalence of mitral valve prolapse and MAD. During a median follow-up of 2534 days, 22 hard cardiac events occurred. At Kaplan-Meier curve (Figure) analysis patients with Dark-Paps were at higher risk of events than those without (p<0.0001). Dark-Paps was significantly associated with hard cardiac events in all the multivariate models performed. Dark-Paps improved prognostic estimation when added to NSVT (p = 0.0006), to LGE (p = 0.005) and to a model including NSVT+LGE (p = 0.014). Dark-Paps allowed a significant net reclassification when added to NSVT (NRI 0.30, p =0.03), to LGE (NRI 0.25, p =0.04), and to NSVT + LGE (NRI 0.32, p =0.02). Conclusions Dark-Paps sign could be considered a novel imaging prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction.