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Original research
Morphology of the mural and commissural atrioventricular junction of the mitral valve
  1. Agata Krawczyk-Ożóg1,2,
  2. Jakub Batko1,
  3. Barbara Zdzierak2,
  4. Artur Dziewierz2,3,
  5. Kamil Tyrak1,
  6. Filip Bolechała4,
  7. Paweł Kopacz4,
  8. Marcin Strona4,
  9. Krzysztof Gil5,
  10. Jakub Hołda1,
  11. Mateusz K Hołda1,6
  1. 1Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland
  2. 2Clinical Department of Cardiology and Cardiovascular Interventions, University Hospital, Krakow, Poland
  3. 32nd Department of Cardiology, Jagiellonian University Medical College, Krakow, Poland
  4. 4Department of Forensic Medicine, Jagiellonian University Medical College, Krakow, Poland
  5. 5Department of Pathophysiology, Jagiellonian University Medical College, Krakow, Poland
  6. 6The University of Manchester, Manchester, UK
  1. Correspondence to Dr Agata Krawczyk-Ożóg, Department of Anatomy, Jagiellonian University Medical College, Krakow 31-034, Poland; krawczyk.ozog{at}


Objective This study investigates mitral annular disjunctions (MAD) in the atrial wall-mitral annulus-ventricular wall junction along the mural mitral leaflet and commissures.

Methods We examined 224 adult human hearts (21.9% females, 47.9±17.6 years) devoid of cardiovascular diseases (especially mitral valve disease). These hearts were obtained during forensic medical autopsies conducted between January 2018 and June 2021. MAD was defined as a spatial displacement (≥2 mm) of the leaflet hinge line towards the left atrium. We provided a detailed morphometric analysis (disjunction height) and histological examination of MADs.

Results MADs were observed in 19.6% of all studied hearts. They appeared in 12.1% of mural leaflets. The P1 scallop was the primary site for disjunctions (8.9%), followed by the P2 scallop (5.4%) and P3 scallop (4.5%). MADs were found in 9.8% of all superolateral and 5.8% of all inferoseptal commissures. The average height for leaflet MADs was 3.0±0.6 mm, whereas that for commissural MADs was 2.1±0.5 mm (p<0.0001). The microscopical arrangement of MADs in both the mural leaflet and commissures revealed a disjunction shifted towards left atrial aspect, filled with connective tissue and covered by elongated valve annulus. The size of the MAD remained remarkably uniform and showed no correlation with other anthropometric factors (all p>0.05).

Conclusions In the cohort of the patients with healthy hearts, MAD is present in about 20% of all studied hearts. The MADs identified tend to be localised, confined to a single scallop. Moreover, MADs in the commissures are notably smaller than those in the mural leaflet.

  • Mitral Valve Insufficiency
  • Heart Valve Diseases
  • Congenital Abnormalities

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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  • Contributors AK-O: concept/design, data acquisition, data analysis and interpretation, drafting of the manuscript, guarantor. JB, AD: data analysis/interpretation, critical revision of the manuscript. BZ: data analysis/interpretation. KT: data acquisition. FB, PK, MS: collection of samples, data acquisition. KG: histological processing and analysis. JH: design, data acquisition, critical revision of the manuscript. MKH: data acquisition, histological analysis, critical revision of the manuscript. All authors approved the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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