Mitral annular disjunction (MAD) is a structural abnormality of the heart in the mitral annulus ring.[1] It is generally defined as an abnormal displacement of the location of where the posterior mitral valve leaflet inserts onto the left atrial wall and the left ventricular wall.[2] This abnormal attachment allows for the mitral valve to become hypermobile and can result in ventricular arrhythmias.[3]
History
editMAD was first described in 1986 through autopsy analysis of hearts while investigating the incidence of mitral valve prolapse.[3] Early work noted that patients who died suddenly often had an abnormal separation of the mitral annulus from the ventricular myocardium.[3]
Pathophysiology
editThe cause of MAD is not well understood. Hypotheses of congenital, degenerative, and acquired structural abnormalities exist.[1] However, the physical characteristics of MAD are able to be observed through a variety of cardiac imaging techniques.[3] Normally the posterior aspect of the mitral annulus is attached to the posterior aspect of the left ventricular wall.[1] In MAD, there is a distinct separation between the mitral annular ring and left ventricular wall.[1] During systole, contraction of the ventricle, the mitral valve leaflet moves away from the ventricular wall and does not move as synchronously as in a heart without MAD.[1] The degree of disjunction can range from a few millimeters to great than 10 millimeters.[1] This abnormal motion is thought to exacerbate mechanical stress on the mitral valve apparatus, promoting myxomatous degeneration and leaflet redundancy. The resulting hyper-mobility may predispose the left ventricle—especially the inferolateral wall and papillary muscles—to stretch-induced fibrosis, which is believed to be an important substrate for ventricular arrhythmias in a mechanism described as the “Padua hypothesis.”[4][5][6]
Diagnosis
editMAD can be found in approximately 30% of patients with mitral valve prolapse, which affects 1-3% of the population.[7] The condition is reported to be more common in women and typically presents as chest pain.[8]
MAD can be diagnosed with echocardiography.[3] Additionally, it can also be diagnosed by cardiac computed tomography and cardiac MRI.[3]
References
edit- ^ a b c d e f Bennett, Sadie; Thamman, Ritu; Griffiths, Timothy; Oxley, Cheryl; Khan, Jamal Nasir; Phan, Thanh; Patwala, Ashish; Heatlie, Grant; Kwok, Chun Shing (August 2019). "Mitral annular disjunction: A systematic review of the literature". Echocardiography (Mount Kisco, N.Y.). 36 (8): 1549–1558. doi:10.1111/echo.14437. ISSN 1540-8175. PMID 31385360.
- ^ "Book Review: Braunwald's heart disease: A textbook of cardiovascular medicine". Perfusion. 37 (7): 026765912211173. 2022-08-12. doi:10.1177/02676591221117347. ISSN 0267-6591.
- ^ a b c d e f Tani, Tomoko; Konda, Toshiko; Kitai, Takeshi; Ota, Mitsuhiko; Furukawa, Yutaka (May 2021). "Mitral Annular Disjunction-A New Disease Spectrum". Cardiology Clinics. 39 (2): 289–294. doi:10.1016/j.ccl.2021.01.011. ISSN 1558-2264. PMID 33894942.
- ^ Basso, Cristina; Iliceto, Sabino; Thiene, Gaetano; Perazzolo Marra, Martina (2019-09-10). "Mitral Valve Prolapse, Ventricular Arrhythmias, and Sudden Death". Circulation. 140 (11): 952–964. doi:10.1161/CIRCULATIONAHA.118.034075. ISSN 1524-4539. PMID 31498700.
- ^ Essayagh, Benjamin; Sabbag, Avi; Antoine, Clémence; Benfari, Giovanni; Batista, Roberta; Yang, Li-Tan; Maalouf, Joseph; Thapa, Prabin; Asirvatham, Samuel; Michelena, Hector I.; Enriquez-Sarano, Maurice (November 2021). "The Mitral Annular Disjunction of Mitral Valve Prolapse: Presentation and Outcome". JACC. Cardiovascular Imaging. 14 (11): 2073–2087. doi:10.1016/j.jcmg.2021.04.029. ISSN 1876-7591. PMID 34147457.
- ^ Dejgaard, Lars A.; Skjølsvik, Eystein T.; Lie, Øyvind H.; Ribe, Margareth; Stokke, Mathis K.; Hegbom, Finn; Scheirlynck, Esther S.; Gjertsen, Erik; Andresen, Kristoffer; Helle-Valle, Thomas M.; Hopp, Einar; Edvardsen, Thor; Haugaa, Kristina H. (2018-10-02). "The Mitral Annulus Disjunction Arrhythmic Syndrome". Journal of the American College of Cardiology. 72 (14): 1600–1609. doi:10.1016/j.jacc.2018.07.070. hdl:10852/68004. ISSN 1558-3597. PMID 30261961.
- ^ Chess, Robert J; Mazur, Wojciech; Palmer, Cassady (2023-01-18). "Stop the Madness: Mitral Annular Disjunction". CASE: Cardiovascular Imaging Case Reports. 7 (3): 116–118. doi:10.1016/j.case.2022.12.004. PMC 10102981. PMID 37065832.
- ^ Carmo, Pedro; Andrade, Maria J.; Aguiar, Carlos; Rodrigues, Rui; Gouveia, Raquel; Silva, José A. (2010-12-09). "Mitral annular disjunction in myxomatous mitral valve disease: a relevant abnormality recognizable by transthoracic echocardiography". Cardiovascular Ultrasound. 8: 53. doi:10.1186/1476-7120-8-53. ISSN 1476-7120. PMC 3014886. PMID 21143934.