Mitral annular disjunction

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Coronal view of heart with labeled mitral valve in yellow Mitral valve * Valvula bicuspide.svg
Coronal view of heart with labeled mitral valve in yellow

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]

Contents

History

MAD 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

The 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]

Transverse view of mitral valve with labeled posterior valve leaflet Mitral Valve RK.png
Transverse view of mitral valve with labeled posterior valve leaflet
Histopathology of mitral valve with myxomatous degeneration Histopathology of mitral valve with myxomatous degeneration.jpg
Histopathology of mitral valve with myxomatous degeneration

Diagnosis

MAD 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

  1. 1 2 3 4 5 6 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.
  2. ↑ "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.
  3. 1 2 3 4 5 6 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.
  4. ↑ 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.
  5. ↑ 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.
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ 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.
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