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Original Investigation
May 27, 2020

Hybrid Positron Emission Tomography/Magnetic Resonance Imaging in Arrhythmic Mitral Valve Prolapse

Author Affiliations
  • 1Helmsley Electrophysiology Center, Icahn School of Medicine at Mount Sinai, New York, New York
  • 2Department of Cardiovascular Surgery, Icahn School of Medicine at Mount Sinai, New York, New York
  • 3The BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
  • 4Division of Noninvasive Cardiovascular Imaging, Icahn School of Medicine at Mount Sinai, New York, New York
JAMA Cardiol. 2020;5(9):1000-1005. doi:10.1001/jamacardio.2020.1555
Key Points

Question  Do patients with primary degenerative mitral valve prolapse, severe mitral regurgitation, and ventricular ectopy have evidence of occult myocardial inflammation or ischemia in addition to characteristic myocardial fibrosis?

Findings  In this study of 20 patients, most patients with severe degenerative mitral regurgitation and ventricular ectopy exhibited myocardial fluorine 18–labeled fluorodeoxyglucose uptake, a surrogate marker of myocardial inflammation. Additionally, the segments of fluorine 18–labeled fluorodeoxyglucose uptake frequently coexisted with areas of myocardial fibrosis, even in asymptomatic patients with normal left ventricular function and dimensions.

Meaning  These findings suggest that patients with degenerative mitral valve prolapse and ventricular ectopy have evidence of subclinical myocardial inflammation or ischemia.

Abstract

Importance  Myocardial replacement fibrosis has been reported to occur in one-third of patients with mitral valve prolapse (MVP) and significant mitral regurgitation (MR). However, it remains unknown whether there are detectable changes in myocardial metabolism suggestive of inflammation or ischemia that accompany the development of fibrosis.

Objectives  To characterize the burden and distribution of fluorine 18–labeled (18F) fluorodeoxyglucose (FDG) uptake and late gadolinium enhancement (LGE) in patients with degenerative MVP and ventricular ectopy.

Design, Setting, and Participants  Prospective observational study of 20 patients with MVP and significant primary degenerative MR who were referred for mitral valve repair and underwent hybrid positron emission tomography/magnetic resonance imaging (PET/MRI). Ventricular arrhythmias were categorized as either complex (n = 12) or minor (n = 8). Coregistered hybrid 18F FDG-PET and MRI LGE images were assessed and categorized. Recruitment occurred in the new patient clinic of a mitral valve repair reference center. This study was conducted from January 11, 2018, to June 26, 2019.

Exposures  Simultaneous cardiac 18F FDG-PET and MRI with LGE imaging on a hybrid PET/MRI system and ambulatory rhythm monitoring.

Main Outcomes and Measures  Patients were categorized by the presence and pattern of FDG uptake and LGE, the severity of ventricular arrhythmias, and the indication for mitral valve surgery.

Results  In the cohort of 20 patients, the median age was 59.5 years (interquartile range, 52.5-63.2 years). Focal, or focal-on-diffuse uptake, of 18F-FDG (PET positive) was detected in 17 of 20 patients (85%). The FDG uptake coexisted with areas of LGE (PET/MRI positive) in 14 patients (70%). Of the 5 asymptomatic patients with normal ventricular indices and absence of any surgical indications, all were PET/MRI positive.

Conclusions and Relevance  In this pilot study, we demonstrate a novel association between degenerative MVP and FDG uptake, a surrogate for myocardial inflammation and/or ischemia. Such evidence of myocardial injury, even in asymptomatic patients, suggests an ongoing subclinical disease process. These findings warrant further investigation into whether imaging for myocardial inflammation, ischemia, and scar has a role in arrhythmic risk stratification and whether it provides incremental prognostic value in patients with chronic severe mitral regurgitation undergoing active surveillance.

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